I have had my Dura heat pump running now and have held my pond temp up at 22 at minimal expense so I am very pleased.
I was however worried by some reports that people had found that during prolonged cold weather the condensation from the heat exchanger froze stopping the unit. Some guys even were using the green house fan heater to keep them unfrozen!
The best solution in various threads was to put a low wattage soil heating cable in the drip tray and this seems to work.
However I gave Dave a call at a call at Heatpumps4pools.com (0844 8806749) as he is always ready to advise and help and he said they had already recognised this problem when these pumps are used for Koi ponds and market a thermostat controlled drip tray heater;
http://www.heatpumps4pools.com/Duratech ... Heater-Kit
A bit pricier than a soil heater cable but no extra mains leads and only comes on when it is needed so it looks like a good solution. I have mine on order.
Peter
Heat Pumps again frozen condensation !
Moderators: B.Scott, vippymini, Gazza, Manky Sanke
Re: Heat Pumps again frozen condensation !
hi Peter
My word the price of these are easily affordable now
do these people do home heating as well as pond heaters ?
thanks for the link
dunc
My word the price of these are easily affordable now
do these people do home heating as well as pond heaters ?
thanks for the link
dunc
-
Manky Sanke
- Site Admin
- Posts: 554
- Joined: Sun Apr 16, 2006 10:24 am
Re: Heat Pumps again frozen condensation !
Duncan,
Yes, heat pumps can be used to heat a house. When I first encountered them for swimming pool hall heating they were called TEC (total environment control) systems because they controlled the environment (obvious). They heated or cooled the air and, since they were designed for pool halls, they dehumidified it as well. All this was done by high level air ducts or underfloor warm air heating and they were very efficient since dehumidification on its own creates waste heat so combining it into warm air heating meant the air was heated with little extra cost so the savings were great because gas heating bill was significantly reduced.
Since then they have been developed into every conceivable use including home heating but be careful of believing sales hype in these situations. I expect you know what COP means, but for anyone else looking in, COP (coefficient of performance) is a measure of efficiency. If a heat pump has a COP of 5, for every 1 kW of electricity it uses, it will give out the equivalent of 5 kW. If you were heating by electricity and changed over to a heat pump, your bill would drop to 20% of the cost of heating by electric heaters.
But, if you are heating by gas and you change over to a heat pump your cost will still be 20% of the cost you would have paid if you were heating by electric heaters, although this may actually be higher than the current gas bill. Just because you change to a heat pump with a COP of 5, it doesn't mean your gas bill will go down to 20%.
Also, since heat pumps produce far less heat in the winter when the air is cold, the house heating is sometimes supplemented by off-peak electricity built into the unit for times when the heat pump can't produce enough heat.
Last point, COPs. Manufacturers like to quote best case figures so be careful what figures they give. A salesman once tried to sell my company a range of heat pumps with the amazing COP of 8 or 9. That would slash customers bills to around 11%. If it sounds too good to be true....
I checked and the heat pumps were made in Spain. When the prototypes were originally tested it was in a hot factory in a heat wave, and they did produce the rated output but if they were imported to the UK where air temperatures are cooler, they could only produce a COP of around 6. That's still pretty good but it isn't 9 so the saving wouldn't be so great.
If all that sounds negative, it isn't meant to be. I like heat pumps. We have a 2 kW heat pump that keeps our pool at 30 C throughout the summer. But they are far more efficient in summer so if you're considering one for winter use, push the salesman to give guaranteed running costs and performance under those conditions rather than just quote sales hype from the glossy brochure which will invariably give the summer performance.
I just looked up one example and changing over from gas heating to a heat pump actually increased the total energy bill by £130. That sounds a bit extreme to me and probably was based on bitterly cold weather through the winter, but it shows that heat pumps don't always bring massive savings.
There is also the problem of them freezing up when the air temperature drops. I've seen models that froze to a block of solid ice when the air temperature dropped below about 10C (plus ten!!). Later developments used some of the heat output to regularly defrost itself but that wastes some of the heat output and slightly reduces the efficiency.
Heat pumps are brilliant in summer but get some firm guarantees before you buy one for winter use.
Peter, if your heat pump was sold for winter use and it freezes up, there is a good argument that it's not fit for the purpose. If an extra heater is required to fix the problem, the manufacturer should supply it free of charge in order to make their product fit for the purpose for which it is sold. Unless, of course, you have bought a summer only one and it was never intended to be used in winter, in which case, if the salesman didn't make that point clear, you have been mis-sold!
This one is an example of a summer only model:
The Duratech ‘Dura Eco’ range of swimming pool heat pumps are the entry models in the Dura range. These models are designed for use in above ground summer only type swimming pools. They are designed for use from April to October where outside temperatures do not go below 8*c.
Read the full details at:
http://www.comfortableclimate.co.uk/dur ... _12kw.html
Yes, heat pumps can be used to heat a house. When I first encountered them for swimming pool hall heating they were called TEC (total environment control) systems because they controlled the environment (obvious). They heated or cooled the air and, since they were designed for pool halls, they dehumidified it as well. All this was done by high level air ducts or underfloor warm air heating and they were very efficient since dehumidification on its own creates waste heat so combining it into warm air heating meant the air was heated with little extra cost so the savings were great because gas heating bill was significantly reduced.
Since then they have been developed into every conceivable use including home heating but be careful of believing sales hype in these situations. I expect you know what COP means, but for anyone else looking in, COP (coefficient of performance) is a measure of efficiency. If a heat pump has a COP of 5, for every 1 kW of electricity it uses, it will give out the equivalent of 5 kW. If you were heating by electricity and changed over to a heat pump, your bill would drop to 20% of the cost of heating by electric heaters.
But, if you are heating by gas and you change over to a heat pump your cost will still be 20% of the cost you would have paid if you were heating by electric heaters, although this may actually be higher than the current gas bill. Just because you change to a heat pump with a COP of 5, it doesn't mean your gas bill will go down to 20%.
Also, since heat pumps produce far less heat in the winter when the air is cold, the house heating is sometimes supplemented by off-peak electricity built into the unit for times when the heat pump can't produce enough heat.
Last point, COPs. Manufacturers like to quote best case figures so be careful what figures they give. A salesman once tried to sell my company a range of heat pumps with the amazing COP of 8 or 9. That would slash customers bills to around 11%. If it sounds too good to be true....
I checked and the heat pumps were made in Spain. When the prototypes were originally tested it was in a hot factory in a heat wave, and they did produce the rated output but if they were imported to the UK where air temperatures are cooler, they could only produce a COP of around 6. That's still pretty good but it isn't 9 so the saving wouldn't be so great.
If all that sounds negative, it isn't meant to be. I like heat pumps. We have a 2 kW heat pump that keeps our pool at 30 C throughout the summer. But they are far more efficient in summer so if you're considering one for winter use, push the salesman to give guaranteed running costs and performance under those conditions rather than just quote sales hype from the glossy brochure which will invariably give the summer performance.
I just looked up one example and changing over from gas heating to a heat pump actually increased the total energy bill by £130. That sounds a bit extreme to me and probably was based on bitterly cold weather through the winter, but it shows that heat pumps don't always bring massive savings.
There is also the problem of them freezing up when the air temperature drops. I've seen models that froze to a block of solid ice when the air temperature dropped below about 10C (plus ten!!). Later developments used some of the heat output to regularly defrost itself but that wastes some of the heat output and slightly reduces the efficiency.
Heat pumps are brilliant in summer but get some firm guarantees before you buy one for winter use.
Peter, if your heat pump was sold for winter use and it freezes up, there is a good argument that it's not fit for the purpose. If an extra heater is required to fix the problem, the manufacturer should supply it free of charge in order to make their product fit for the purpose for which it is sold. Unless, of course, you have bought a summer only one and it was never intended to be used in winter, in which case, if the salesman didn't make that point clear, you have been mis-sold!
This one is an example of a summer only model:
The Duratech ‘Dura Eco’ range of swimming pool heat pumps are the entry models in the Dura range. These models are designed for use in above ground summer only type swimming pools. They are designed for use from April to October where outside temperatures do not go below 8*c.
Read the full details at:
http://www.comfortableclimate.co.uk/dur ... _12kw.html
Re: Heat Pumps again frozen condensation !
Hi guys;
Totally agree with all Manky has said as my only option is an immersion type electric heater which I used last winter, the heat pump represents a potential way to reduce elec bill.
I have not had a problem with mine freezing as I have not had it long enough I do however have another one that air cons the bedrooms in summer and warms them in the winter and it has been excellent with no freezing even last winter. I have put the pond one in a warm south facing corner near the house one, the de-icer was a precaution as I had read threads of problems. I got a good deal on the de-icer kit in exchange for giving the seller a spread sheet showing temps (ambient and water) and electricity consumption which I monitor continuously (there I go again admitting I have OCD!).
And Manky you were right in your earlier advice. As I left the immersion heater in line after the heat pump and it is controlled by a Digistat which is deliberately designed to prevent rapid cycling of the heater, by setting the Digistat 2 deg below the heat pump control which also is designed to prevent rapid cycling, I have nice smooth pond temps. So no complex control panels !
Peter
Totally agree with all Manky has said as my only option is an immersion type electric heater which I used last winter, the heat pump represents a potential way to reduce elec bill.
I have not had a problem with mine freezing as I have not had it long enough I do however have another one that air cons the bedrooms in summer and warms them in the winter and it has been excellent with no freezing even last winter. I have put the pond one in a warm south facing corner near the house one, the de-icer was a precaution as I had read threads of problems. I got a good deal on the de-icer kit in exchange for giving the seller a spread sheet showing temps (ambient and water) and electricity consumption which I monitor continuously (there I go again admitting I have OCD!).
And Manky you were right in your earlier advice. As I left the immersion heater in line after the heat pump and it is controlled by a Digistat which is deliberately designed to prevent rapid cycling of the heater, by setting the Digistat 2 deg below the heat pump control which also is designed to prevent rapid cycling, I have nice smooth pond temps. So no complex control panels !
Peter
-
Manky Sanke
- Site Admin
- Posts: 554
- Joined: Sun Apr 16, 2006 10:24 am
Re: Heat Pumps again frozen condensation !
Peter,
Having an electric heater as a back up is a very sensible idea. Heat pumps usually have a thermostat built in that is designed to switch them off if the air temperature falls below a certain value. When it is warm COPs of 4, 5 or 6 can be expected but COPs (their efficiency) fall as the air temperature falls. There would come a point when the COP would be less than 1 which would mean that for every 1 kW the heat pump used, it would produce less than 1 kW equivalent output so the thermostat switches them off to prevent this situation.
This would mean that, when it became really cold and your pond needed the most heat, the heat pump would just be switched off waiting for warmer weather and the pond would go cold. Worse than that would be a situation where the air temperature was hovering just about at that temperature for a while. The heat pump would alternately switch on and off and the pond temperature would yo-yo.
Heat pumps wouldn't switch off very often in a typical British winter and the "on and off" yo-yo effect would be a rare event, but a back up electric heater is good insurance to be there ready to switch on just in case.
I design smart control panels, someone asked about a panel to control multiple heaters and I recall giving someone this advice a few weeks ago (if it was you Peter, sorry for repeating myself). I don't believe in complicated systems where they aren't necessary, the simplest solution is usually the best. If you have heater, such as a heat pump, that you would prefer to use and another heater, such as an electric heater that is there as a back up, you don't need complicated controls. Just plumb the preferred heater before the back up heater and set the back up slightly lower.
In this situation, if the heat pump is making a useful contribution to heating the pond, the water going into it will be at pond temperature and the water coming out will be a degree or two warmer. The electric heater, straight after, will only see water that is slightly warmer than the pond. It won't know that the pond temperature needs raising unless the heat pump can't cope or has switched off. In this case, the water will now be going to the electric heater at pond temperature and the electric heater stat will see the true pond temperature. Then it will switch on or off accordingly.
When the heat pump starts making useful heat again, the water coming out of it and going to the electric heater will be warmer and it will be fooled into thinking that the pond temperature has risen so it will switch off.
As I remember, the question about a control panel was regarding how to dump solar heat into a pond when it was available. In this case, I suggested putting the solar heat before the heat pump. By exactly the same process as above, when solar heat was available the warmer water being fed to the heat pump then to the electric heater would switch them both off.
In this situation, when solar was available, it would heat the pond. When it wasn't but the heat pump could make heat, it would heat the pond. The electric heater would only ever switch on when neither solar nor heat pump heat was available.
Easy peasy, automatic change over from one heater to another without a control panel. (Don't worry about me losing potential customers, I'll starve quietly).
Having an electric heater as a back up is a very sensible idea. Heat pumps usually have a thermostat built in that is designed to switch them off if the air temperature falls below a certain value. When it is warm COPs of 4, 5 or 6 can be expected but COPs (their efficiency) fall as the air temperature falls. There would come a point when the COP would be less than 1 which would mean that for every 1 kW the heat pump used, it would produce less than 1 kW equivalent output so the thermostat switches them off to prevent this situation.
This would mean that, when it became really cold and your pond needed the most heat, the heat pump would just be switched off waiting for warmer weather and the pond would go cold. Worse than that would be a situation where the air temperature was hovering just about at that temperature for a while. The heat pump would alternately switch on and off and the pond temperature would yo-yo.
Heat pumps wouldn't switch off very often in a typical British winter and the "on and off" yo-yo effect would be a rare event, but a back up electric heater is good insurance to be there ready to switch on just in case.
I design smart control panels, someone asked about a panel to control multiple heaters and I recall giving someone this advice a few weeks ago (if it was you Peter, sorry for repeating myself). I don't believe in complicated systems where they aren't necessary, the simplest solution is usually the best. If you have heater, such as a heat pump, that you would prefer to use and another heater, such as an electric heater that is there as a back up, you don't need complicated controls. Just plumb the preferred heater before the back up heater and set the back up slightly lower.
In this situation, if the heat pump is making a useful contribution to heating the pond, the water going into it will be at pond temperature and the water coming out will be a degree or two warmer. The electric heater, straight after, will only see water that is slightly warmer than the pond. It won't know that the pond temperature needs raising unless the heat pump can't cope or has switched off. In this case, the water will now be going to the electric heater at pond temperature and the electric heater stat will see the true pond temperature. Then it will switch on or off accordingly.
When the heat pump starts making useful heat again, the water coming out of it and going to the electric heater will be warmer and it will be fooled into thinking that the pond temperature has risen so it will switch off.
As I remember, the question about a control panel was regarding how to dump solar heat into a pond when it was available. In this case, I suggested putting the solar heat before the heat pump. By exactly the same process as above, when solar heat was available the warmer water being fed to the heat pump then to the electric heater would switch them both off.
In this situation, when solar was available, it would heat the pond. When it wasn't but the heat pump could make heat, it would heat the pond. The electric heater would only ever switch on when neither solar nor heat pump heat was available.
Easy peasy, automatic change over from one heater to another without a control panel. (Don't worry about me losing potential customers, I'll starve quietly).
Re: Heat Pumps again frozen condensation !
Hey guys and girls;
I have struck up a good relationship ( I trust him) with the supplier of my Dura & pump and he has provided the following information and has given me permission to post it here. I voiced the forums specific questions with him and these were the answers;
In response to your queries:-
1. Have you seen the COP curve for the Dura+ range? This shows how the output varies with air temp.
see http://www.heatpumps4pools.com/myfiles/ ... 10a%29.pdf
Assuming your water is around 13c (the green line) the COP is around 4 at 0c and 3 at -5c.
eg the Dura+7 draws 1.2kw of power
At 0c it will output 1.2 x 4 = 4.8kw and at -5c 1.2 x 3 = 3.6kw etc.
The heat pump still produces more output than it’s input power even at low temps.
I normally size the units at 0c allowing some surplus power where possible. In extremely cold weather a backup heat source may be required.
It is however worth remembering that the heat pump can be used all year round providing cost savings. Many koi keepers forget this and just focus on its performance during the depths of winter at say -15c.
2. I appreciate your point on this. I am in talks with various manufacturers to design a heat pump specifically for the koi market. This will have the tray heater fitted as standard. We could of course supply one with all of the current heat pumps to be used on koi ponds, but this would increase the price by c £100. Not all owners experience an ice build up and so it is not always required. Some owners live in milder climate areas and do not suffer from ice build up.
Now that the kit is available, we always offer it with the heat pump when we know that the unit will be used on a koi pond.
Kind regards
David
Tel: 0844-8806749
www.HeatPumps4Pools.com
Good positive honest response I thought. Mine is working fine.......pond at 21 average 24 hour ambient temp 12 deg. Daily elec consumption by pump 8 Kw hours.
Peter
I have struck up a good relationship ( I trust him) with the supplier of my Dura & pump and he has provided the following information and has given me permission to post it here. I voiced the forums specific questions with him and these were the answers;
In response to your queries:-
1. Have you seen the COP curve for the Dura+ range? This shows how the output varies with air temp.
see http://www.heatpumps4pools.com/myfiles/ ... 10a%29.pdf
Assuming your water is around 13c (the green line) the COP is around 4 at 0c and 3 at -5c.
eg the Dura+7 draws 1.2kw of power
At 0c it will output 1.2 x 4 = 4.8kw and at -5c 1.2 x 3 = 3.6kw etc.
The heat pump still produces more output than it’s input power even at low temps.
I normally size the units at 0c allowing some surplus power where possible. In extremely cold weather a backup heat source may be required.
It is however worth remembering that the heat pump can be used all year round providing cost savings. Many koi keepers forget this and just focus on its performance during the depths of winter at say -15c.
2. I appreciate your point on this. I am in talks with various manufacturers to design a heat pump specifically for the koi market. This will have the tray heater fitted as standard. We could of course supply one with all of the current heat pumps to be used on koi ponds, but this would increase the price by c £100. Not all owners experience an ice build up and so it is not always required. Some owners live in milder climate areas and do not suffer from ice build up.
Now that the kit is available, we always offer it with the heat pump when we know that the unit will be used on a koi pond.
Kind regards
David
Tel: 0844-8806749
www.HeatPumps4Pools.com
Good positive honest response I thought. Mine is working fine.......pond at 21 average 24 hour ambient temp 12 deg. Daily elec consumption by pump 8 Kw hours.
Peter
-
Dave Collins
- Nurse Shark
- Posts: 90
- Joined: Sun Aug 05, 2007 10:48 am
- Location: Nr Strasbourg, France
Re: Heat Pumps again frozen condensation !
Good figures Peter, is this with pond covered or not?Brockp wrote:
Good positive honest response I thought. Mine is working fine.......pond at 21 average 24 hour ambient temp 12 deg. Daily elec consumption by pump 8 Kw hours.
Peter
Dave
Re: Heat Pumps again frozen condensation !
Dave the pond is covered with double layer polycarb.
Peter
Peter
-
Dave Collins
- Nurse Shark
- Posts: 90
- Joined: Sun Aug 05, 2007 10:48 am
- Location: Nr Strasbourg, France
Re: Heat Pumps again frozen condensation !
I hoped it would be Peter or it would mean that mine is not so good. I have a 7kw unit from David and for a difference of +9°C then I have an average consummation of 9.99kw for 24hrs. Note that the difference can be from any actual average outside temperature, I don’t heat my pond as high as yours.Brockp wrote:Dave the pond is covered with double layer polycarb.
Peter
I too have a spreadsheet of data with average temperatures taken at 8h00 every day from the local International airport and of course the pond. Once covered I hold at 15°C and then slowly drop down to 10°C for the end of December by following the temperature down during very cold days. I started to increase the temperature on 9th March this year.
The heat pump is, as David said to me, too small for the size of pond and once uncovered I limit the pond to +5°C more than the average temperature as any more and the heat pump can’t cope. This was a personnel choice to prevent me from spending too much money on heating.
One thing I did was buy a digistat to control the temperature to +/- 0.1°C. I also had problems with the drain freezing up and have recently installed one of David’s tray heating systems. Hopefully it will solve the problem but of course since installing it the weather has been kind, don’t expect it to last.........
Dave
Re: Heat Pumps again frozen condensation !
Hi Dave
I have a couple of Didgistat’s on my pond and I think they are great bits of kit because of their "intelligent" approach to temp control.
How did you wire your Digiststat into the heat pump ? did you just use the out put from the stat straight to the heat pump with its own stat set to a high level or did you bypass the pumps intrenal controls completely?
Peter
I have a couple of Didgistat’s on my pond and I think they are great bits of kit because of their "intelligent" approach to temp control.
How did you wire your Digiststat into the heat pump ? did you just use the out put from the stat straight to the heat pump with its own stat set to a high level or did you bypass the pumps intrenal controls completely?
Peter
-
Dave Collins
- Nurse Shark
- Posts: 90
- Joined: Sun Aug 05, 2007 10:48 am
- Location: Nr Strasbourg, France
Re: Heat Pumps again frozen condensation !
Hi Peter,
I wired it in series with the flow control of the heat pump. The heat pump is set to run at a higher temperature as you say.
At the minute I'm waiting for the weather to change (not really in a hurry) to test the drain heater. For the time being I've wired it to the external pump output from the heat pump so that its only on when the heat pump is running. As you know its 75 watts and although not too much there is no point in wasting electric. I have a very special tarif here which is cheap except for 22 days of the year when I get charged 10 times the normal price for each kw so I stop the machine, again using a relay in series in the flow circuit.
Dave
I wired it in series with the flow control of the heat pump. The heat pump is set to run at a higher temperature as you say.
At the minute I'm waiting for the weather to change (not really in a hurry) to test the drain heater. For the time being I've wired it to the external pump output from the heat pump so that its only on when the heat pump is running. As you know its 75 watts and although not too much there is no point in wasting electric. I have a very special tarif here which is cheap except for 22 days of the year when I get charged 10 times the normal price for each kw so I stop the machine, again using a relay in series in the flow circuit.
Dave
Re: Heat Pumps again frozen condensation !
Hi Dave
Thanks for that advice most useful. It would make sense if the instructions told you to wire the heating kit on the terminals used when the heat pimp controls the circulation pump then the heating would only come on when the heat pump was running. Is this what you did?
I have recalibrated the stat that comes with the heating kit to come on at +1. I am assuming that when it is plus 1 in the incoming air that heat pump will be running all the time and the condensation in the out going air will be in the minus range i.e. about to freeze. I will tinker with it during the winter. At the moment the pond is at 19 and the air temp is varying from +11 during the day to +5 at night (on average). I have been using, again on average 9KW per day on heating so not bad.
The other thing I have done is move my air pump supplying the aerated bottom drain to the top of my airing cupboard and piped the air to the pond through an airline inside a garden hose for some extra heat insulation. The pond temp raised 1 deg C just from supplying hot/warm air instead of ambient air. Free hot air central heating for the pond!
Peter
Thanks for that advice most useful. It would make sense if the instructions told you to wire the heating kit on the terminals used when the heat pimp controls the circulation pump then the heating would only come on when the heat pump was running. Is this what you did?
I have recalibrated the stat that comes with the heating kit to come on at +1. I am assuming that when it is plus 1 in the incoming air that heat pump will be running all the time and the condensation in the out going air will be in the minus range i.e. about to freeze. I will tinker with it during the winter. At the moment the pond is at 19 and the air temp is varying from +11 during the day to +5 at night (on average). I have been using, again on average 9KW per day on heating so not bad.
The other thing I have done is move my air pump supplying the aerated bottom drain to the top of my airing cupboard and piped the air to the pond through an airline inside a garden hose for some extra heat insulation. The pond temp raised 1 deg C just from supplying hot/warm air instead of ambient air. Free hot air central heating for the pond!
Peter
-
Dave Collins
- Nurse Shark
- Posts: 90
- Joined: Sun Aug 05, 2007 10:48 am
- Location: Nr Strasbourg, France
Re: Heat Pumps again frozen condensation !
Hi Peter,
Free hot air central heating for the pond eh, sounds good.
The wiring instructions with the heating kit say to wire the kit directly to a 230V supply but this would mean that it switches on independent of the heat pump. Your solution of recalibrating the thermostat is a good solution and one that I might well adopt as well. Being connected to the circulating water pump outlet means that it starts heating, if cold enough, 3 minutes before the heat pump runs and continues for 3 minutes afterwards.
Last winter I had a lot of trouble with the drain freezing up and after 3 or 4 days, depending on temperature, the ice had built up enough to block the fan. It has already formed ice this year, a couple of weeks ago we had 2 nights at 0°C. So its trial and error, if there is no freezing then OK but if there is then I can always connect it as directed. Assuming it works then I can then try your method of recalibrating the heating kits thermostat to a lower level to save even more.
My reason for doing this is as I said before, I have cheap electric but for 22 days per year my 70 watts heater suddenly turns into a 700 watt heater as far as cost is concerned but without the heat.
Current temperatures here are max 15°C & min 7°C which is good but it won’t last so I’m busy doubling up on my pond insulation.
Dave
Free hot air central heating for the pond eh, sounds good.
The wiring instructions with the heating kit say to wire the kit directly to a 230V supply but this would mean that it switches on independent of the heat pump. Your solution of recalibrating the thermostat is a good solution and one that I might well adopt as well. Being connected to the circulating water pump outlet means that it starts heating, if cold enough, 3 minutes before the heat pump runs and continues for 3 minutes afterwards.
Last winter I had a lot of trouble with the drain freezing up and after 3 or 4 days, depending on temperature, the ice had built up enough to block the fan. It has already formed ice this year, a couple of weeks ago we had 2 nights at 0°C. So its trial and error, if there is no freezing then OK but if there is then I can always connect it as directed. Assuming it works then I can then try your method of recalibrating the heating kits thermostat to a lower level to save even more.
My reason for doing this is as I said before, I have cheap electric but for 22 days per year my 70 watts heater suddenly turns into a 700 watt heater as far as cost is concerned but without the heat.
Current temperatures here are max 15°C & min 7°C which is good but it won’t last so I’m busy doubling up on my pond insulation.
Dave
-
Dave Collins
- Nurse Shark
- Posts: 90
- Joined: Sun Aug 05, 2007 10:48 am
- Location: Nr Strasbourg, France
Re: Heat Pumps again frozen condensation !
Hi Peter,
Well although its now warmed up again I did have a cold spell of 10 days with fog everyday, a heat pumps nightmare. The results of the tray heating kit are mixed.
I taped the heating element with aluminum tape, as shown on the instructions, to the bottom of the tray next to the heat exchanger on the fan side. It kept the bottom of the tray clear on this side but the ice formed further up the heat exchanger, leaving a gap of one inch ice free. On the reverse side of the heat exchanger the ice formed as usual. I have fitted a 30w trace heater at the back and await results of this when we have another cold spell.
Dave
Well although its now warmed up again I did have a cold spell of 10 days with fog everyday, a heat pumps nightmare. The results of the tray heating kit are mixed.
I taped the heating element with aluminum tape, as shown on the instructions, to the bottom of the tray next to the heat exchanger on the fan side. It kept the bottom of the tray clear on this side but the ice formed further up the heat exchanger, leaving a gap of one inch ice free. On the reverse side of the heat exchanger the ice formed as usual. I have fitted a 30w trace heater at the back and await results of this when we have another cold spell.
Dave
Re: Heat Pumps again frozen condensation !
Hi Dave;
With the temps we have been having in the south I am almost tempted to set my pump to heat and cool not just heat ! I am trying to keep my pond at 10 ish for a winter for the koi but it is now at 12 because the ambient air temp has been so high. S no ice this year (saying that that is bound to curse me) but they are forecasting a bit colder month down here. The problem with no cold weather is a) I cannot experiment and b) I don't know how this pump will work if we do have cold spell and knowing my luck the first real test would come when I am away.
Peter
With the temps we have been having in the south I am almost tempted to set my pump to heat and cool not just heat ! I am trying to keep my pond at 10 ish for a winter for the koi but it is now at 12 because the ambient air temp has been so high. S no ice this year (saying that that is bound to curse me) but they are forecasting a bit colder month down here. The problem with no cold weather is a) I cannot experiment and b) I don't know how this pump will work if we do have cold spell and knowing my luck the first real test would come when I am away.
Peter