New Heat pump - v high standby consumption

[zilp]

no the compressor would run full speed every time it makes hot water. Not only when it is cold outside.

Would it? Mine pulls ~ 2 kW at current outdoor temperatures, so far from full power. Though no idea how that's dristributed between compressor and fan.

Also ... 210 l takes ~ 244 Wh to heat 1 K, so if we assume 10 K hysteresis, full power 12 kW at CoP of 3 would heat that thing in 4 minutes!? Or rather, it wouldn't, because I'd think that small-ish tank can't absorb 36 kW at reasonable supply temperatures!?

[Siwastaja]

You surely must have some consumer protection laws, and authorities you can talk to, without taking it to the court?

[woodchips]

I bought a Hydropro Premium 14 swimming pool heat pump heater at an auction. Output 14kW. The controller was dead, but a new replacement included and just tried it, new controller doesn't communicate over the serial bus, error.

Anyway, pretty simple inside, connect mains to compressor and fan and off it goes. In this mode it is actually cooling the water, and gets impressively cold. Only using a few gallons of water in a bucket with a small circulating pump.

There is a 4 way valve, operating that and changes to heating. Again impressive performance on the limit water, hets too hot to put a finger on the compressor pipe so >60C.

Measured consumption at 240V was about 11A on cooling and 15A on heating.  This ties in reasonably well with the stated consumption.

Question, why is the heating consumption greater than the cooling consumption? The four way valve just reverses the direction of gas flow through the compressor?

On a very quick test it would seem that these swimming pool heat pumps are a good thing. Air to water so easy to get into the house to use the heat. What needs some more testing is how well it works with an air temperature below 10C, not at 25C.

[Siwastaja]

I bought a Hydropro Premium 14 swimming pool heat pump heater at an auction. Output 14kW. The controller was dead, but a new replacement included and just tried it, new controller doesn't communicate over the serial bus, error.

Anyway, pretty simple inside, connect mains to compressor and fan and off it goes. In this mode it is actually cooling the water, and gets impressively cold. Only using a few gallons of water in a bucket with a small circulating pump.

There is a 4 way valve, operating that and changes to heating. Again impressive performance on the limit water, hets too hot to put a finger on the compressor pipe so >60C.

Measured consumption at 240V was about 11A on cooling and 15A on heating.  This ties in reasonably well with the stated consumption.

Question, why is the heating consumption greater than the cooling consumption? The four way valve just reverses the direction of gas flow through the compressor?

On a very quick test it would seem that these swimming pool heat pumps are a good thing. Air to water so easy to get into the house to use the heat. What needs some more testing is how well it works with an air temperature below 10C, not at 25C.

I'd say open a new thread. Anyway, are you sure the thing doesn't have an EEV (electric expansion valve, basically a stepper motor)? If it does, to recreate the dead controller, you also need to feedback the EEV to keep the process in control (usually measuring and keeping superheat constant). If you fail to do that, worst case you get refrigerant enter the compressor in liquid form, killing the compressor in little time. If the thing has capillary tube or TEV (thermal expansion valve), then you don't have to do anything.

[woodchips]

Thanks for your reply.

Yes, it has a connector marked Electronic Expansion Valve, 5 wires , but disappears into the depths of the heat pump and can't see what it is or does.

When I first tried to get it working I just paralleled the compressor, fan and 4 way valve together and connected the mains. Quickly started making I am not happy noises. If I delay operating the 4 way valve for 30 seconds or so then runs quietly. The 4 way valve swaps between heating and cooling.

[Siwastaja]

Thanks for your reply.

Yes, it has a connector marked Electronic Expansion Valve, 5 wires , but disappears into the depths of the heat pump and can't see what it is or does.

When I first tried to get it working I just paralleled the compressor, fan and 4 way valve together and connected the mains. Quickly started making I am not happy noises. If I delay operating the 4 way valve for 30 seconds or so then runs quietly. The 4 way valve swaps between heating and cooling.

A great way to get the compressor destroyed. EEV absolutely needs to be properly controlled, otherwise compressor sucks in liquid refrigerant which removes the oil and it's permanently dead soon after that.

[langwadt]

Thanks for your reply.

Yes, it has a connector marked Electronic Expansion Valve, 5 wires , but disappears into the depths of the heat pump and can't see what it is or does.

When I first tried to get it working I just paralleled the compressor, fan and 4 way valve together and connected the mains. Quickly started making I am not happy noises. If I delay operating the 4 way valve for 30 seconds or so then runs quietly. The 4 way valve swaps between heating and cooling.

A great way to get the compressor destroyed. EEV absolutely needs to be properly controlled, otherwise compressor sucks in liquid refrigerant which removes the oil and it's permanently dead soon after that.

https://www.macscool.co.za/compressor-failures-liquid-slugging/