Downstairs RAD's hot when hot water on....not 3 way valve.

Hi there,

We have a problem with our heating. When we switch on the hot water our downstairs radiators get scorching hot..way hotter than our thermostat is set at.

We have a maintenance plan with British Gas and they have replaced the 3 way actuator about 5 times and even replaced the actual valve as well but it doesn't seem to make a difference. They have suggested it is sludge that's causing the problem and tried to encourage a powerflush but I have run sludge remover through the system and hosed through every radiator and the water runs fairly clean.

I have no idea why it would do this and it has done ever since we have lived here. I assume it must be just that the pipework is like that? I am willing to fit TRV valves on all the downstairs radiators but that seems like just masking the issue rather than solving it.

Any suggestions would be welcome. If it helps we have a back boiler system, a hot water cylinder in the spare room which is pumped. I really know very little about plumbing so sorry if i'm a little vague.

poss it s getting reverse circulation.

wheest said:

Hi there,

We have a problem with our heating. We have a maintenance plan with British Gas and they have replaced the 3 way actuator about 5 times and even replaced the actual valve as well but it doesn't seem to make a difference. They have suggested it is sludge that's causing the problem and tried to encourage a powerflush but I have run sludge remover through the system and hosed through every radiator and the water runs fairly clean.

I have no idea why it would do this and**** it has done ever since we have lived here****. Any suggestions would be welcome. If it helps we have a back boiler system, a hot water cylinder in the spare room which is pumped. I really know very little about plumbing so sorry if i'm a little vague.

Click to expand...

Good old BG it`s been piped wrong from the start

It amazes me how many of our engineers (I'm a BG engineer) can't sus a wrongly piped system, especially as changing the valve didn't cure the problem. Did the TSM get involved as on our patch we are supposed to call tsm on third visit.
BG would usually charge you toput this problem right (if they ever work out how )

wheest said:

Hi there,

We have a problem with our heating. When we switch on the hot water our downstairs radiators get scorching hot..way hotter than our thermostat is set at....

Click to expand...

Which stat? Boiler, room or cylinder.
Has it ever been ok?
When did it go wrong?

can you see where the hot water return joins back into the system? It probably joins in before the downstairs rad circuit, so the hot water return is warming the rads, changing the 3 way valve won't do sh*t.

Thanks for all the reply's.

I had an incling that it was just piped up wrong.

*g20 - I wouldn't have a clue where to look to be honest. I'm quite happy to give it a go if you can give me any guidance.

*bengasman - Its very difficult to pinpoint when or if it "went" wrong all of a sudden. As we had economy 7 we had always heated our water using that. About 5 or 6 years ago we had a radiator moved in the kitchen and it caused an airblock. When BG came round to get rid of the airblock he suggested we didn't use economy7 as it wasn't any cheaper, so that's when we noticed. As mentioned several BG visits later over a number of years and it's never been fixed, so we have continued to use the economy 7. Only a few weeks ago we got economy 7 disconnected completely and went onto a normal electricity plan so we need to sort out the hot water now. As for brands I will have to check.

*twgas - I don't know if a TSM got involved really. The last guy that came round suggested again that it was sludge. He gave me some sludge remover & inhibitor. I will be draining down the system to fit a heated towel rail at the weekend so I'll sort out the sludge remover then & the inhibitor in due course.

My wife & I have lived in the house for the last 8 years but can't really remember a particular point it went wrong, equally we can't remember a particular time of it working properly either...sorry. We are expecting our first child in December and would like it sorted by then. If the easiest option is to fit TRV's on the RAD's that get hot I'll do that.

It's quite simple to check if it's been plumbed in wrong.

Look around the building, has an extension been added or any alterations.

Now assuming there has, turn the rads off with both valves, and the backflow should stop.

If not turn each rad off in turn untill the problem is found ( a newer rad, hall, utility and bathroom ) are the first place to look.