Faulty 2 Port Valve?

ragj195 · 11 Oct 2009

Hi

I have a single 2 port valve above my Potterton boiler which from what I've read controls the flow of water to the rads. The valve seems to open and close correctly when CH is selected on the programmer BUT when CH is OFF and the valve is closed the outlet pipe to the rads is still hot and some of the rads still get hot, not very hot but still hot. If I turn CH on, either on the programmer or I open the valve manually with the little lever I can feel the outlet pipe get very hot so I guess open is working fine. If on turn CH off I can see the lever close but it seems somehow hot water is till getting through. Is it possible that the valve is faulty and is closing but not closing all the way thereby still letting water though? If so then do I need to replace the whole valve or just the actuator?

Thx

Richard

seco services · 11 Oct 2009

poss crud is in the port restricting the closing of the valve or the paddle in the valve is faulty and letting water past.

doitall · 11 Oct 2009

What is the model of the boiler.

Is there another valve for the hot water,
is there a by=pass valve,

twgas · 11 Oct 2009

I should think the whole valve needs replacing.
To check it turnsystem off and allow to go cold.
Once cold turn the hot water on ONLY, if the pipe from the valve to rads and the rads get hot the valve needs replacing. You would also more than likely benefit from some form of system cleaning to help prevent the same problem recurring.
If however the pipe stays cool and rads get hot your system is pipe wrong.

ragj195 · 11 Oct 2009

Thanks.

Its a potterton RS80. There doesn't seem to be any other valves. When I chatted with the last CH guy that came round he metioned having to add a second valve for isolated CH and HW control.

There is one other manual valve near the cyclinder with a circular handle which I've been told is an old way of controlling the amount of flow to the HW cyclinder.

Thx

nicknox · 11 Oct 2009

The valve is probably letting by but assuming this the make of valve would be a good start before repairs are attempted.

ragj195 · 11 Oct 2009

TWGAS

When the system is cold and I turn HW on only the valve stays closed but the pipe to the rads gets warm/hot and the first couple of rads get warm/hot. If I then hold the pipe and manually open the valve with the other hand it definitly fully opens as it then becomes too hot to touch.

KR
Richard

doitall · 11 Oct 2009

Is it a recent problem or an always done it problem.

ragj195 · 11 Oct 2009

Been in the house for 2 years and I've only just decided to find out why HW ON means CH kind of ON. Previsouly in the summer when I didn't want CH on I would just turn off all the rads.

So no it's not a recent problem it could have been like this for years!

doitall · 11 Oct 2009

I suspect an installation fault, which is why I asked.

nicknox · 11 Oct 2009

From the OPs original description it still sounds as if the valve is passing though.

bengasman · 12 Oct 2009

Are we not simply talking about an ancient c-plan that is finally collapsing?

pgod3 · 12 Oct 2009

this could be the valve not closing correctly and letting by possible sludge in the water. could also be installation fault with the return from the cylinder not being the last connection on the system with the 3 rads being connected after the cylinder. This could cause the returning water from the cylinder to be heating the rads

D_Hailsham · 12 Oct 2009

bengasman said:
Are we not simply talking about an ancient c-plan that is finally collapsing?

C Plan has the valve on the HW return, not the CH flow.

ragj195 · 12 Oct 2009

Thanks for the discussion guys. I've let it run for a while with the CH off and the valve in the closed position and it seems that all the rads are getting hot, not as hot as when CH is on but hot still. If I set CH to on they then get hotter i.e normal for on.

In my mind from what I can see it really seems like the valve isn't closed but is this common with valves? If it isn't then I guess it must be something else. I don't want to drain the sytem down and replace the valve unless the odds are in my favour.

The rads also seem to get hot in sequence.

Thx

Richard

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Faulty 2 Port Valve?

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