Hi PaulB,

Welcome to the forum.

You have obviously got too much insulation, you need to drill some holes in the walls. 😎

Joking apart, are these upper floor rooms? Heat rises.

Do they have large windows? Solar gain.

What controls do you have for individual rooms and for the overall system?

Please provide more information about location of warm rooms and the controls being used etc.

@paulb, welcome to the forums Paul. 

Addressing your room temperatures, do they all have rads and are the rads definitely off despite the thermostats saying they're only set to heat to 16-18C. The thermostats might not be connected to the ASHP and may not be calling for heat (or telling it turn off). So if there's one zone calling for heat, and your rads are all on, the rooms will continue to heat up. This is the biggest dilemma for ASHPs (in my opinion) which is why we put smart TRVs on all our rads to regulate room temperatures more effectively. 

What TRVs do you have on your rads? 

Hi We have underfloor heating so no radiators. Most rooms have a room thermostat that connects via an interface to the ASHP. The interface confirms the temperatures displayed in each room and that batteries are sufficient etc. We have found that reducing the set point in warm rooms has little effect on the temperature. Not sure whether the heating is overdoing it or just that rooms are above the set point because of solar gain? 

Hi Paul,

If you could carry out the following tests and feedback the results, it may be possible to home in on the root cause of the problem.

If you have a suitable thermometer, then measure the temperature of the floor in each room and record the results. Take the reading somewhere away from direct sunlight so that there is no effect from solar gain.

It is difficult problem solving from afar, so I ask that you be my eyes and ears and perform a few simple tests. If this is a problem then please let me know.

There should be one or more headers (a larger bore pipe with a number of smaller bore pipes connected to the larger one) that feed the warm water to the different areas of UFH. Do you know where they are located and could you send a photo?

@derek-m thanks - great idea we’ll just need to locate the box with the thermometer in! Will take photos too and send through - much appreciated 

Hi Paul,

Thanks for the update.

Are the warmer rooms South facing? Do you know what a solenoid valve is?

Hi Derek

The house is south east facing and was built 10 years ago as an ‘eco’ house by a builder who then lived in it until sold to us last month. There is a panel on each floor containing the manifolds and the receivers from each room thermostat (I’ve added photos). I assume each zone has a small solenoid.
I’ve taken the floor temperature in each room and they are broadly the same as the room stats. The set point for each room is mostly 18 degrees so in all rooms the actual temperature is higher. This ranges from 19.4 office with just a light well to 25.7 top floor bedroom with 2 Vellux windows south facing.  We know that the stats communicate with the interface as the values can also be seen there plus the battery condition. 

Hope this helps - let me know if you need any more info. Really appreciate your input.

Hi Paul,

Thanks for the information and photo's, which are highly useful.

The upper manifold, in the second picture, is for the warm water supply from the central heating pump. The small devices with the red ring would appear to be flow meters. I think they are more likely to be what would normally be called 'metering valves' rather than actual flowmeters. They are used to adjust the flow rate to each of the individual UFH loops, so that larger loops would have a higher flow rate than smaller loops.

The lower manifold is the return, and the blue coloured devices are what Uponor call actuators. They could be solenoids or possibly small electric motors, either way their task is to open and close the valves for each UFH loop.

Before making any adjustments, touch each of the pipes in turn and see if any are warmer than the others. This would indicate that there has recently been water flowing through that particular UFH loop, or that the corresponding valve is passing. Make a note of any pipes that are warmer.

On each of the blue actuators there should be a perspex window, if you can see a white marker then this would indicate that the actuator is operated and the corresponding valve should be open.

With someone to help, raise and lower the temperature setting of each room thermostat in turn, and check that the corresponding actuator operates and opens and closes the valve. The temperature of the flow and return pipes should increase, the flow first followed by the return. This test will also prove that each thermostat is operating the correct actuator.

If everything is connected to the correct place and is working as it should, then your problem may be due to solar gain, or merely the fact that heat rises and will accumulate in the upper rooms, or even a combination of both. Your could try hanging white sheets or blinds or something similar to try to reduce the solar gain in the warmer rooms. If this proves that solar gain is the culprit, it is possible to get solar reflective windows. JulianC has them installed so he may be able to give you better advice.

Let us know what you discover.

Hi Paul,

Did you discover the cause of your warmer rooms, or is the warmer weather making testing difficult?