New combi boiler but one cold radiator Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Bizzielizzie]

I recently had my very old boiler replaced in my one bedroom flat by a combi boiler and ever since the replacement, the radiators haven't been as hot. This could be because the TVRs weren't working before and I couldn't regulate the temperature of individual radiators. Now, the radiator that is furthest away from the boiler gets warm at the top but stays cold at the bottom. The heating engineers have been round 3 times, changed the TVRs and fiddled around with balancing the system. The problem radiator heats up for about 30 mins (while the engineer is there) , then goes cold again (once he's gone) . Could this be a boiler problem as the radiators worked perfectly before the change of boiler? The new boiler is a Vaillant 824 Eco-Tec condensing combination boiler and there are 5 radiators in my one bedroomed flat. The engineers assure me that the boiler is sufficient enough to heat the property but I'm just not convinced. I'm at the end of my tether, especially as the cold radiator is in the room where I spend the most time. Can anyone suggest solutions I can put to the engineers as they are at a loss?

[htg engineer]

If that radiator goes cold, and the rest are hot I would say it was the TRV's at fault.

Remove the thermostatic head and see how that goes, if it still happens there's a problem with the pump or pipework restricting the flow to the radiator.

Also open up the lockshield valve slightly.

htg

[Bizzielizzie]

[quote="htg engineer"]If that radiator goes cold, and the rest are hot I would say it was the TRV's at fault.

Remove the thermostatic head and see how that goes, if it still happens there's a problem with the pump or pipework restricting the flow to the radiator.

Also open up the lockshield valve slightly.

htg[/quote]

Many thanks for your reply. I can't seem to get the TRV off the radiator. I've opened the valve fully at the other end and turned all the other radiators off with the TRVs (except one that doesn't have a TRV fitted). It's worked a treat. The problem radiator is hot all over. I will turn each radiator back on one at a time to see ehich one makes a difference to the temperature.

Will opening the valve fully on the radiator damage it in any way? Shouldn't the heating engineers be experimenting with the radiators like this?

[htg engineer]

Yes the engineer should be trying this, if you have a problem with one radiator the first thing to check are the valves the next is to balance the system.

Balancing is when you open/close lockshield valves so that all radiators heat evenly. If they were more precise they would check the temperature drop between the flow and return and adjust so that there's about a 11 degree celsius difference. Not all engineers have the equipment to check this properly. I use a Telegan Sprint V2 which is very accurate, but expensive to purchase.

Opening the valves on the radiator fully will not damage it in anyway.

"I will turn each radiator back on one at a time to see ehich one makes a difference to the temperature." How did this go, any problems ?

htg