Marvin Posted October 18, 2022 Share Posted October 18, 2022 Further to @Temp's reply in @joe90's topic Can we keep the lights on this winter? Our ASHP has it's own main electric meter with nothing else connected. Testing over hours, it appears that my previous estimation of the standby power consumption is about right. The results for our ASHP on standby is a rate of about 82-84 watts, so total used for 24 hour standby is 1.968-2.016kWh assuming no power used for the heat protection of the ASHP. This was measured with an outside temperature no lower than 8.8C over the last 24 hours and no lower than 9.9C during the period of measurement. Bearing in mind that the ASHP compressor must be warm enough to work without causing excessive wear, and requires 12 hours of standby after the outside temp achieved rises above 5C, this may mean that we cannot turn the ASHP back on for 12 hours after a power cut! I hope every ASHP owner with the same compressor requirement is aware of the dilemma of either having no heating for 12 hours or risking excessive wear of the compressor. Marvin 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted October 18, 2022 Share Posted October 18, 2022 At 2 kWh a day, that is, at current rates, about £250/year. Now I have no idea what you could realistically get for your ASHP on eBay, or how much a new one with a decent compressor would cost. But I would be considering it at today's energy prices (though I think they will come down). Link to comment Share on other sites More sharing options...
Marvin Posted October 18, 2022 Author Share Posted October 18, 2022 17 minutes ago, SteamyTea said: At 2 kWh a day, that is, at current rates, about £250/year. Now I have no idea what you could realistically get for your ASHP on eBay, or how much a new one with a decent compressor would cost. But I would be considering it at today's energy prices (though I think they will come down). Yes... However nothing these days seems that simple....The ASHP is not on standby all the time because it is used now and then. During the year when the average 24 hour temperature is above 16C we don't need the ASHP on. Link to comment Share on other sites More sharing options...
JohnMo Posted October 18, 2022 Share Posted October 18, 2022 Put it on weather compensation so it runs all the time, set the flow temp as low as you can, should give a good CoP and no standby. At setback 2 degrees. 1 Link to comment Share on other sites More sharing options...
joth Posted October 18, 2022 Share Posted October 18, 2022 7 minutes ago, JohnMo said: Put it on weather compensation so it runs all the time, set the flow temp as low as you can, should give a good CoP and no standby. At setback 2 degrees. Doesn't address the OP issue that after a (regular, planned) power cut you somehow need to lock out the ASHP from operating for 12 hours or risk excessive wear on the compression. 1 Link to comment Share on other sites More sharing options...
JohnMo Posted October 18, 2022 Share Posted October 18, 2022 That's not standby - that's warming up. Why it takes 12 hours is bonkers and doesn't sound realistic. What does the operation manual say? 2 Link to comment Share on other sites More sharing options...
joe90 Posted October 18, 2022 Share Posted October 18, 2022 I need to find out if my compressor needs warming up or not as I plan to run it from a timer to take advantage of PV. Link to comment Share on other sites More sharing options...
SteamyTea Posted October 18, 2022 Share Posted October 18, 2022 2 minutes ago, joe90 said: I need to find out if my compressor needs warming up or not as I plan to run it from a timer to take advantage of PV. Can you find your model here? https://www.carrier.com/commercial/en/uk/products/heating-air-conditioning/air-to-water-heat-pumps/ Link to comment Share on other sites More sharing options...
dpmiller Posted October 18, 2022 Share Posted October 18, 2022 where has it been stated that a 12h warmup is needed? 2 Link to comment Share on other sites More sharing options...
Marvin Posted October 18, 2022 Author Share Posted October 18, 2022 2 hours ago, dpmiller said: where has it been stated that a 12h warmup is needed? For mine, I checked with the manufacturer to understand why on page 27 it says to 'ensure power is on ahead and heating at least 12 hours for crankcase' Link to comment Share on other sites More sharing options...
dpmiller Posted October 18, 2022 Share Posted October 18, 2022 So it looks like the Carel inverter is looking after crankcase heating, but I can't see any adjustable setpoints. As well as the enable in User Mask, there is a line in the inverter setup screen for auto/manual, and another showing current. Unsure whether this is a band heater or injecting into the motor coils tho... I'd opine that the 12h is very conservative, bearing in mind that the unit is rated for down to -20C, and also the Sprsun manual makes NO reference to this necessary delay. Link to comment Share on other sites More sharing options...
Marvin Posted October 18, 2022 Author Share Posted October 18, 2022 24 minutes ago, dpmiller said: So it looks like the Carel inverter is looking after crankcase heating, but I can't see any adjustable setpoints. As well as the enable in User Mask, there is a line in the inverter setup screen for auto/manual, and another showing current. Unsure whether this is a band heater or injecting into the motor coils tho... I'd opine that the 12h is very conservative, bearing in mind that the unit is rated for down to -20C, and also the Sprsun manual makes NO reference to this necessary delay. Would it be the Carel or some form of low temp heater in the unit? Hence the ~90w an hour power usage? Link to comment Share on other sites More sharing options...
dpmiller Posted October 18, 2022 Share Posted October 18, 2022 2 minutes ago, Marvin said: Would it be the Carel or some form of low temp heater in the unit? Hence the ~90w an hour power usage? :unsure: , I'm going to look into it Link to comment Share on other sites More sharing options...
HughF Posted October 18, 2022 Share Posted October 18, 2022 (edited) 38 minutes ago, dpmiller said: :unsure: , I'm going to look into it It's wired on output NO6 from the Carel pCO - a switched 230 output. Easy enough to disconnect if it's an annoying parasitic load. Edited October 18, 2022 by HughF 1 Link to comment Share on other sites More sharing options...
Marvin Posted October 18, 2022 Author Share Posted October 18, 2022 Hi @dpmiller. Just a thought. I assume you know our model is a Cool Energ inverTech Air Source Heat Pump CE-iVT9 with a Carel interface. I noticed you wrote about a Sprsun manual, which I had to look up to know what a Sprsun was. M Link to comment Share on other sites More sharing options...
dpmiller Posted October 18, 2022 Share Posted October 18, 2022 1 minute ago, HughF said: It's wired on output NO6 from the Carel pCO - a switched 230 output. in which case it's under active control. I'll try to get a look at ours early in the morning if it's cold overnight and see if it's on, and if the run current is displayed. Certainly the PVE lubricant required for the panasonc compressor specced is less demanding of heat than earlier POE oils Link to comment Share on other sites More sharing options...
dpmiller Posted October 18, 2022 Share Posted October 18, 2022 Just now, Marvin said: Hi @dpmiller. Just a thought. I assume you know our model is a Cool Energ inverTech Air Source Heat Pump CE-iVT9 with a Carel interface. I noticed you wrote about a Sprsun manual, which I had to look up to know what a Sprsun was. M Yes, the manufacturer is Sprsun 1 Link to comment Share on other sites More sharing options...
joe90 Posted October 19, 2022 Share Posted October 19, 2022 I am struggling to find out if my Aeromax ASHP (carrier) has the type of compressor that needs heating to stop wear as I was planning to put it on a timer to benefit from PV during daylight hours, any pointers please 🙏 Link to comment Share on other sites More sharing options...
Marvin Posted October 19, 2022 Author Share Posted October 19, 2022 Hi @joe90 Is that a Kingspan Aeromax ASHP? Can you not contact the manufacturer? Link to comment Share on other sites More sharing options...
joe90 Posted October 19, 2022 Share Posted October 19, 2022 Just now, Marvin said: Hi @joe90 Is that a Kingspan Aeromax ASHP? Can you not contact the manufacturer? I guess so, I bought it on EBay as a punt, works very well but wondered if anyone else had found out about theirs? Link to comment Share on other sites More sharing options...
Marvin Posted October 19, 2022 Author Share Posted October 19, 2022 3 minutes ago, joe90 said: I guess so, I bought it on EBay as a punt, works very well but wondered if anyone else had found out about theirs? I think the issue has only just arisen because of: Suggested power cuts in the UK in Jan/Feb. Enquiries regarding other, ASHP's instructions stipulating 12 hour on standby before firing up. Me being a mean sod wondering why my ASHP uses 2kWk a day on standby. I think it was expected that ASHP's in the UK would be left on at least standby all the time especially during winter for frost/freezing protection. 1 Link to comment Share on other sites More sharing options...
Luke1 Posted October 19, 2022 Share Posted October 19, 2022 (edited) Just to add, the Nibe installer menu says this for the F2040 models: You can also see that the 8kW model uses approx 30W in crankcase heater mode. Even in the middle of summer I've not often seen my system use anything less than the 30W, and Nibe won't confirm what conditions must be met for the system to enter standby or thermostat off mode. I have only ever seen power usage drop when the outdoor unit air temperature exceeds 42C (In the sun during the heat wave) Edited October 19, 2022 by Luke1 1 Link to comment Share on other sites More sharing options...
joe90 Posted October 19, 2022 Share Posted October 19, 2022 27 minutes ago, Marvin said: Me being a mean sod wondering why my ASHP uses 2kWk a day on standby. +1, I must get a clamp to see what it is drawing on standby, I guess that will tell me. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted October 19, 2022 Share Posted October 19, 2022 Just now, joe90 said: +1, I must get a clamp to see what it is drawing on standby, I guess that will tell me. You can use one of the ones I left there. Just need to clamp it around the L or N to the ASHP and then keep an eye on the display. Will be close enough to let you know what is being drawn most of the time. Leave it in a day, week or month and it will give you those numbers. It may need a new battery as it has been at yours for a few years now. Link to comment Share on other sites More sharing options...
joe90 Posted October 19, 2022 Share Posted October 19, 2022 1 minute ago, SteamyTea said: You can use one of the ones I left there. Oh yes, I will look into that on my return later this week. Thanks 👍 Link to comment Share on other sites More sharing options...
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