One Radiator Only Get Luke Warm - Tried (Almost) Everything.

[TazzyK]

Hi all,

First post here so I hope I don't bore you all but I need some help with getting one radiator to work, and I think I will need to provide some thorough background on this.

We have 13 radiators in the house - 6 on the ground floor, 5 on the first floor, 1 in the attic, and 1 in the basement. The boiler is located on the ground floor at the far end of the house. The problematic radiator is also on the ground floor at the front of the house.

Initially, we had a Worcester 24CDi boiler and the problematic radiator never worked properly since we moved in a few years ago. We've recently changed the boiler to a Vaillant EcoTec Pro 28 and all of a sudden the problematic radiator started working. I thought that the last boiler was probably not powerful enough to feed this radiator, but now it's stopped working again.

This may be a coincidence, but I had to have the engineer out to fix an issue with the wireless thermostat, and rather than leaving the heating demand (or something like that) on auto, he put it down to 24Kw (same as the old boiler output?).

Also, I've seen various videos etc on youtube and various guides on balancing the radiators and checking the TRV. The TRV pin is not stuck. The flow side does not have a lockheed(?) type fitting but another valve with + and - on it (as do the rest of them). I can get the flow into the radiator to get readlly hot (as hot as the other radiators to the touch), but the radiator only manages to get luke warm and the TRV side stays cold. Even the flow isn't stable as the pipe does suddenly go cold and needs fine adjustment.

At this point, I'm thinking (hoping) that either this valve or the TRV are faulty.

What do yoo guys (the professionals) think? If this is the case, is there anyway to change these without draining the system (short of using those expensive brackets as shown on dragons den?)

Any help and advice greatly appreciated.

 

[Best]

If the rad works okay when others are turned off, then system needs balanced properly, or there is a blockage in the pipe(s) to that rad or faulty valve. Very slow flow to rad can result in the flow pipe side getting hot but the rad staying nearly cold.
Get the radiator isolated & drained/taken off & flush it with mains water garden hose. Then have each of its valves opened into a hose to flush & check them for good flow. Probably better a plumber does this.

 

[hammers4spanner]

as above really , lify off rad and blast through withb garden hose .
probably pay to buy new valves as could be faulty i would also consider cutting out some pipe work

 

[IDCHAPPY]

The valves are cross piped, the flow should have the TRV on it and the return have the lockshield valve, not that it's a biggy, just worth pointing out.
I'd go for blockage or balancing too

 

[scorps]

24kw is the highest you get on any vaillant combi on the heating side, if the offending rad is the last in line and the pipework isn't graded correctly it will never get as hot as the other rads.Although you said it did when it was first converted to the Vaillant. Even if it's nearest to the boiler the system could at one time had a cylinder and mot valve in cylinder cupboard therefor leaving this rad the furthest,I bet it's not sludge

 

[0304Driver]

Best thing to do before removing the rad is with the heating on, turn off all the other rads, and see if the rad gets hot, if it does get hot it is a system design/balancing problem. If it does not get hot remove the trv head and make sure the other valve is open fully, you say the pin is not stuck but it could be a faulty trv head, if it still does not get hot you will need to do further investigations which would then mean disconnecting the rad and draining etc