@enc I am using TRVs upstairs as its always hot up here and cold down there - so you aren't alone. Are you using a room thermostat?

@batalto oh that is good to know! Single thermostat is downstairs in the chilly hallway so whilst we have one, yes, it’s just keeping the pump running and never actually reaches temp and turns it off

Posted by: @enc

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@derek-m I have been fiddling around trying to balance the rads. The lockshield valves were fully open on all of them, but in all honesty I think my attempts at balancing have just caused the rads at the top of the house to not get as much heat (when trvs are fully open on all radiators) rather than encouraging the ones down the bottom to get hotter. I think this is possibly because they were already all getting the same amount of heat, but I think the heat loss at the bottom of the house is greater with it being lower and we have a cat flap which probably doesnt help keep the heat in. 

I am going to keep trying but is there any harm in them all being open if they are heating evenly like this?

I have another new question too. Do you know what the temperature offset on the heating controller is for? It is currently set to 5 degrees but unsure of what this is doing or achieving. Usage is still about 24 kwh per day whatever I seem to do :).

 

Thanks,

 

Emma

Radiators are balanced to even out the temperatures around your home, with all the valves as fully open as possible to achieve the desired temperatures. If you close in all the valves it just restricts the water flow around the system. The radiators downstairs will only get as hot as the water coming from the heat pump.

If your system is in weather compensation mode then the 5C would indicate that the calculated value has been increased by 5C. This is the weather compensation offset which can be used when the rooms are a little too hot or a little too cold. It is also an easy way to set back the temperature overnight should it be required to do so.

If you are happy with the indoor temperatures when the controller display is indicating 5C, it would indicate that your weather compensation curve is set too low. Try changing the offset to 4C and see if the indoor air temperature starts to fall. If so, then check the settings of your weather compensation curve.

@enc your pump is probably (and I'm guessing here) reaching a high return water temperature (close to the inlet temp) and just turning off automatically as it thinks there is no need to heat the water anymore. Have you balanced your radiators yet?

Posted by: @enc

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My radiators also seem to be getting warm and then near cooling down repeatedly throughout the day. Is this normal?

Hi Emma,

Do you have normal thermostats on system? If so then turn them up to a setting 2C above the desired room temperature.

@derek-m ok so if I am understanding correctly lockshields and TRVs as open as possible is the idea, so long as all the rads are getting an even temp?

I am not sure what you mean by the 5 degrees above the calculated temp? As in an offset off 5 degrees will always heat the water 5 degrees higher than what is calculated from the curve? Does this mean if we wanted an overnight set back we would manually adjust this to -5 at that time? 

I am happy to let the curve do its own thing, so maybe then I should have it at 0?

Thank you, Emma

@derek-m hi, its not the termostat that is downstairs and set much higher than the room is reaching

Posted by: @enc

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@derek-m ok so if I am understanding correctly lockshields and TRVs as open as possible is the idea, so long as all the rads are getting an even temp?

I am not sure what you mean by the 5 degrees above the calculated temp? As in an offset off 5 degrees will always heat the water 5 degrees higher than what is calculated from the curve? Does this mean if we wanted an overnight set back we would manually adjust this to -5 at that time? 

 

I am happy to let the curve do its own thing, so maybe then I should have it at 0?

 

Thank you, Emma

 

In an ideal World your WC curve would be perfectly adjusted to match your home, so as the outside air temperature varies, the indoor air temperature would remain constant. Because there are other factors, besides the outdoor air temperature, which could affect the indoor air temperature, the WC offset is provided as a temporary measure to save having to keep re-adjusting the WC curve. If you set the WC offset to 0, then the Leaving Water Temperature (LWT) from your heat pump will be reduced and the indoor air temperature may fall.

You have mentioned that your radiators are getting warm and then cooling down, this should not be happening if your heat pump is running correctly in WC mode.

Do you have any other water pumps in your system or a buffer tank or Low Loss Header (LLH)?

@derek-m understood regarding the temperature offset! I will have that on zero for now then whilst I am still learning. 

No other pumps or buffer tank or low loss header I don't think... 

Is the thermostat on the water tank implicated in the heating at all. I know that is out of sync with the controller or something (from the last service) and as a temporary fix we just have it set a bit lower than to 45 degrees our controller demands to compensate.

Posted by: @enc

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@derek-m understood regarding the temperature offset! I will have that on zero for now then whilst I am still learning. 

No other pumps or buffer tank or low loss header I don't think... 

Is the thermostat on the water tank implicated in the heating at all. I know that is out of sync with the controller or something (from the last service) and as a temporary fix we just have it set a bit lower than to 45 degrees our controller demands to compensate.

Is the thermostat on the water tank associated with the immersion heater? If so, it has nothing to do with the central heating.

If your radiators are heating up and cooling down, then your heat pump must be running for a period of time then stopping for a period of time. The display on the controller may indicate when the heat pump is running, so record the on and off period. When you have a record of the timing then set the WC offset value from 5 to 0, and see if the timing of the on and off periods is changed.