Single Pipe Valve / TRV Help

[Ashley Bacon]

I have a single pipe system (Yes I know most people will say upgrade to 2 pipe). I have installed Honeywell TRV and have some issues (Rads not getting hot) which I believe are due to the TRV (reduced flow), have tried bleeding rads, balancing etc. If I take the TRV head off they heat, put it on they don't.

It seems Danfoss are probably the only single pipe TRV manufacturers. I'm looking at the 2 options but they are silly expensive.
Danfoss RA-G15 angled valve 1/2 | Wolseley

Danfoss radiator fixed sensor 5-26c | Wolseley

If I used a manual valve would that be compatible, I appreciate they wont be 'thermostatic' but at leas I can turn them up and down as needed to get heat to the Rads.
Myson Fullflow angled valve wheel head 15mm x 1/2 Chrome Plated | Wolseley

Or are there issues with certain flow through manual valves? Another other suggestions?

 

[Harvest Fields]

If you put the danfoss trv version on they will work normally. A standard rad valve only restricts flow not temp

 

[OffshoreGas]

I had a 1 pipe system in a previous house, never had any issues with it. A lot of guys would replace because it’s not what they’re used to. You haven’t got a pump forcing water through the rad so you can find sludge builds up if you don’t use inhibitor etc.

 

[Ashley Bacon]

It’s a new combi boiler and new rads and has has inhibitor. Didn’t realise it was one pipe until the engineer came to install the boiler, it always worked fine before hence I think the issue is the trv.

 

[Harvest Fields]

It’s a new combi boiler and new rads and has has inhibitor. Didn’t realise it was one pipe until the engineer came to install the boiler, it always worked fine before hence I think the issue is the trv.

If you have changed all that. Makes sense to convert to a 2 pipe.

 

[Ashley Bacon]

Probably but it was ok before and the effort to get the carpet, floorboards was too much and not costed in.

 

[Harvest Fields]

Probably but it was ok before and the effort to get the carpet, floorboards was too much and not costed in.

Was it pressurised before?

 

[OffshoreGas]

Probably but it was ok before and the effort to get the carpet, floorboards was too much and not costed in.

Its about £40/radiator for TRVs compatible with a 1 pipe system. It'll probably cost you about the same to run a second pipe.

 

[Ashley Bacon]

Was it pressurised before?

No