mystery TRV configuration on radiators & problems with them ?

[JB]

HELP ! I've been in this house now for 1.5 years and have had a nightmare with this CH system (only 6 years old) It's a conventional boiler with CH and HW loops, open vented. I have 2 issues that are kind of related really so here we go.

1. When we moved in the first thing I noticed was that the TRVs were sometimes on the flow and sometimes on the return. Is this wrong, if so how serious an issue is it for the performance of the system ??? Is there grounds for quizzing/pushing the installer ???

1. 2 of the radiators have been really problematic, kitchen and spare bedroom. They hardly get warm despite me having many attempts at correctly balancing the rads. All rads upstairs close to the pump are turned down almost fully and still heat up really quick. I've been through most of the posts and FAQs on this too. When I switch all other rads off and just keep these two on ONLY the spare bedroom rad responds and really hots up. This has a TRV on the return (as the lsv side gets hot first ???). The kitchen one only just warms a little along the top and the return stays cold and has a TRV on it. I have had both rads off the wall, flushed them (all clear) and both flow and returns are clear of blockages. The kitchen rad fails to heat even when its the ONLY one switched on. Mind blowing !!! The kitchen rad is just new last week, flow and return seem blockage free and the flow freely once the lsv and trv are opened without rad.

Is there anything here that jumps out to you guys as to what could be happening here because I'm going mad with this.

Much appreciate any help here.

Jonathan

[Bovvered?]

Apologies for this dumb suggestion, but have you bled the rads? The kitchen rad failing to heat up sounds like an airlock

[robgraham]

I would have thought that if the kitchen radiator is getting warm "along the top", it doesn't need bleeding. But having just had a TRV fail on me ( and had the hassle of fitting isolators so that I could change it !) I will make the dumb suggestion of that being a possibility - in fact having read the post again, it would seem a distinct probability given that the pipes and radiator seem clear.

Rob

[Dave Plowman (News)]

Some TRVs can be used on either flow or return. Look for an arrow on the body. If there isn't one it probably means they are ok.

Sounds like you're guessing this. Lockshield valves ain't linear in operation. You might find it only needs to be open a quarter turn. Get yourself a thermometer and measure the in and out temperatures as per the FAQ on balancing - you have read it carefully?

[JB]

=A0 London SW

cheers fellas for the comments so far. All TRVs on the whole system have arrows pointing both directions of flow. I guess that means they can be located on either the flow or return ??? I have opened the kitchen rad from the return side whilst the flow was closed and rad plugged with a cork. About 5-6 litres came out freely which i returned to the expansion tank. Would an airlock have cleared by now if there was one ??? I haven't had time to drain the flow yet but my gut feeling is that it's ok. Dave said that LSVs aren't linear in operation......the kitchen rad flow is controlled by a LSV.....surely gradually closing it down will reduce flow into the rad making my problem worse ???? I wonder if the spare bedroom and kitchen rads are adjacent to each other on the system........will I drain return water from the spare room rad??? cheers for anymore advice or comments guys. jonathan

[Ed Sirett]

In theory, if they don't chatter, bang, groan or whine then they are OK.

I ave opened the kitchen rad

You could have a partial blockage of the pipes feeding the rad. Especially if one blockage could cause both problems.

What happens when you shut down all the other rads (with their TRVs)? Do you get a hot rad in the kitchen? The ktichen rad need to be opened up fully (minus a bit to stop it jamming) on the lockshield side.