Radiators upstairs cold hot downstairs?

[Rich Kellett]

Any help / guidance welcome - radiators upstairs (middle and top floor of house) cold but warm downstairs. Have recharged the system as pressure was zero. Also bled radiators upstairs - initially no water or air coming out of top floor ones but now water comes out but no heat. System has red expansion tank with pressure gauge connected to outlet from main cylinder. Also what appears to be a white expansion tank connected to balanced cold mains. Both expansion tanks connected via heating filling loop (which I opened to recharge the red tank). 2 wall thermostats (bottom and top floors of house). Have had heating on for half a day with both thermostats at max, pressure is maintained, but still no heat in upstairs rads.
Red tank appears to have water in it when I tap it - white one sounds empty. Red tank shraeder valve let’s air out, nothing coming out of white shraeder valve. Pump plate checked and seems ok and can hear it running. Both the main cylinder and the cold water combination valve have separate valves that when I turn them allow water to flow. Main cylinder one pipework runs to base of red expansion tank and pressure gauge, and cold water combination valve one pipework runs to base of both expansion tanks.
Anyone got any ideas for getting heat back upstairs?? Thanks, Rich.

 

[transam]

2 stats = 2 heating zones =‘2 motorised valves ?

1 upstairs heating ?
1 down stairs heating ?

Does the up stairs zone valve open ?

 

[Rich Kellett]

Hi transam. The upstairs wall thermostat clicks as it passes 19degrees. There are 2 white components in the airing cupboard pipework - they have a manual and auto setting via a lever on the top - are they zone valves? Thanks.

 

[Rich Kellett]

E323B449-DFE4-4678-85B0-27D8DBCF181C

• Rich Kellett
• 26 Mar 2021

Zone valves??

 

[Rich Kellett]

Here’s a photo of the system.

 

[transam]

Yes they are zone valves

you would have 3 ???

2 heating zones ? 1 upstairs 1 down stairs
1 hot water zone ?

1st port of call would be is the up stairs zone valve actually opening
If it does not than upstairs won’t work

danfoss make by the looks of it
2 screws will undo and the heads or motors which can be removed / detached from the body no need to drain system

my guess is either the motor / actuater is not working or the valve body is stuck and seized and the motor cannot turn it / open it

???????

 

[Rich Kellett]

Thanks. I’ve moved the levers from auto to manual. I can feel resistance and hear the motor running on only one of them. I guess that’s the issue? thanks transam. I’ll disconnect the faulty one and have a closer look. Thanks again

 

[transam]

Remember

the valve has to be told to open

via programmer
To
Room thermostat

than to the valve

The valve than opens and tells the boiler / pump to switch on

 

[Rich Kellett]

Had another play around - it appears it’s the valve that I can hear and feel resistance on when I move from auto to manual that is at fault. When it’s in auto there no heat upstairs, flip it to manual and I get heat! I guess that means the boiler could be on permanently if not in auto mode?
The other valve lever just flops from manual to auto but in auto position it seems to work.

 

[transam]

In most cases when a motorised valve is energised the lever will be floppy

The manual lever is generally to allow the valve to be opened for draining down / maintenance ect
Providing u create a demand via the other 2 valves and keep the duff valve open or remove the head from its body and leave valve open heating will work up stairs
Replacement heads are generally readily available from various merchants

 

[Rich Kellett]

Awesome thanks for all the help. Much appreciated.

 

[Rich Kellett]

So I replaced the Danfoss HPA2 valve and now have heating upstairs again; however, this time it’s not being regulated by the thermostat. The heating is on when the programmer tells it but it is fully on for that duration with no regulation regardless of temperature set on thermostats. Anyone got any ideas? (Thermostats are Danfoss RMT230, I’ve had the covers off but can’t see any issues - all wiring appears sound).

 

[Rich Kellett]

So I replaced the Danfoss HPA2 valve and now have heating upstairs again; however, this time it’s not being regulated by the thermostat. The heating is on when the programmer tells it but it is fully on for that duration with no regulation regardless of temperature set on thermostats. Anyone got any ideas? (Thermostats are Danfoss RMT230, I’ve had the covers off but can’t see any issues - all wiring appears sound).

Read more: https://www.diynot.com/diy/threads/radiators-upstairs-cold-hot-downstairs.567716/#ixzz6rjPAtDWa

 

[transam]

the entire valve or just the motor / actuater ?

room stat makes and breaks a live to actuater ( brown wire) opens the valve

brown wire on valve motor should be dead when the stat switches off or is turned down / off

grey wire on actauater is permanently live

orange is switch live to boiler / pump

blue is neutral

afai recall there s no earth on that brand ?

 

[Rich Kellett]

Thanks transam. It was just the actuator. I followed the previous wiring - all the wires (blue, brown and orange) from all actuators were in the same terminals. Only separate one from the actuator was the grey. May be that the room stat live brown is not seated well/correctly in the terminal. Will have another look. Thanks.