Combi Heating - Hot rads downstairs, cold rads upstairs

RedBalloon

Have my central heating on tonight.
For some reason the radiators are lovely and toasty downstairs but stone cold upstairs.
All valves are set to max, but the hot water isn't getting upstairs (the pipes to the bedroom radiators are cold at the base).
Anything I should try before getting a plumber out?

Edited to add: the bathroom towel radiator is also lovely and hot!

ThisIsWeird

I presume it all working fine last time it was used?
Q - do you have separate zones? More than one room 'stat?
All valves open to max? Well, close the downstairs ones and see if that now heats the up.
Q - do you have a magnetic filter on the return to your boiler? If so, have you checked it?

RedBalloon

ThisIsWeird said:

I presume it all working fine last time it was used?
Q - do you have separate zones? More than one room 'stat?
All valves open to max? Well, close the downstairs ones and see if that now heats the up.
Q - do you have a magnetic filter on the return to your boiler? If so, have you checked it?

Really appreciate your response - it's chilly up there this evening!

I have just one stat which operates all. Never been an issue (tiny house).
Worked fine back in April/May whenever I switched it off. When I've had it on recently I haven't had it on for long so didn't notice upstairs heating up or not.
Valves are open to the max everywhere. Radiators bled (just in case).
Regarding the magnetic filter I don't know. I don't know how to check this either.....

Eldi_Dos

Are the pins in TR Valves opening up, if they have been off for awhile they can sometimes stick in closed position.

RedBalloon

Eldi_Dos said:

Are the pins in TR Valves opening up, if they have been off for awhile they can sometimes stick in closed position.

I did wonder, but wasn't sure how to check this without forcing / breaking them?
Saying that though, the pipes to the thermostatic valves are cold.

jefaz07

RedBalloon said:

Eldi_Dos said:

Are the pins in TR Valves opening up, if they have been off for awhile they can sometimes stick in closed position.

I did wonder, but wasn't sure how to check this without forcing / breaking them?
Saying that though, the pipes to the thermostatic valves are cold.

Take the heads off. 

ThisIsWeird

Things to try:
1) Turn off the downstairs rads temporarily and see if the upstairs rads now come on. Do that?
2) Remove the TRV head from each rad to check the valve's operation. Do this by opening the TRV to max, ie '5'. Then unscrew the chrome knurled collar under the control head anticlockwise - it should only be hand-tight. If it's tight, then turn it along with the head - it'll rotate a fraction. Then hold it whilst you turn the head back clockwise the same fraction. Then anticlock them both - and so on. Once the head is off, you'll see a metal pin. Press it down firmly - it should move smoothly and bottom out with a firm thunk. On release it should pop up instantly. Does the rad come on with the head removed?

Eldi_Dos

If any of the pins are stuck in the closed position I have heard that heating valve body with a hairdryer can help free the pin.

ArbitraryRandom

Turn all downstairs rads off at their TRVs. Turn all but one, of upstairs rads off by TRVs - does that radiator heat up?

What pressure does the boiler show?

Does the boiler fire instantly when the heating is switched on or does it take a couple of seconds to 'click'? 

Lorian

How many zone valves do you have.

ThisIsWeird

Lorian said:

How many zone valves do you have.

One. I asked