Central heating question - 3-way valve

[ci_newman]

Hi all,

With the warmer months coming along (and therefore turning off the central heating) it has become apparent that there is a problem! Even with the central heating turned off and the thermostat set to minimum (its an old manual jobby and I can hear it click), I am still getting hot water coming through to the radiators.

I've tested the system with and without H/W and C/H and the 3-way MPV valve motor does seem to be changing (I can hear the motor turning) however the water flow continues.

Is this likely to point at a failed valve and if so, how easy are they to change out? I'm pretty handy with my electrics and I've replaced / installed various service taps etc.

Help! It's getting too hot in my house at the moment!

 

[Werewolf]

If the valve is in the airing cupboard or somewhere similar (not built into the boiler), replacing the 3 way valve is relatively easy - you need to turn off the water and boiler, partially drain the system then it should be a case of taking off the motorised head (usually 2-4 screws, note which way up it sits), undoing the 3 nuts holding it to the pipework and lifting it off.
Clean the pipes, apply some PTFY tape around the threads on the new valve, put it on, tighten up the nuts and fill the system again (have someone ready to turn the water off if need be).

The longest part of the job will probably be draining the water.

This is assuming it's not a sealed system or anythign like that.

Plumbing tends to be pretty easy, just never expect it to work first time round, or start a job on a day when the shops aren't open, or you're in a rush (Murphy dictates that if you don't have time to spend on it, then what should be a 15 minute job will take all day).

 

[monkeysmith]

I was surprised recently how easy it is to fiddle/change with the heating system. Amazing how many people panic and just call out a plumber, can cost shedloads.

 

[mick4545]

I cured a sticking 3 way valve in my boiler with WD40.

 

[Werewolf]

I was surprised recently how easy it is to fiddle/change with the heating system. Amazing how many people panic and just call out a plumber, can cost shedloads.

Aye for less than the cost of a single call out you can generally get most of the primary tools, and a stock of common parts to see you through most normal plumbing "emergencies".

In general the water side of plumbing is pretty simple, if sometimes time consuming.

 

[ci_newman]

If the valve is in the airing cupboard or somewhere similar (not built into the boiler), replacing the 3 way valve is relatively easy - you need to turn off the water and boiler, partially drain the system then it should be a case of taking off the motorised head (usually 2-4 screws, note which way up it sits), undoing the 3 nuts holding it to the pipework and lifting it off.
Clean the pipes, apply some PTFY tape around the threads on the new valve, put it on, tighten up the nuts and fill the system again (have someone ready to turn the water off if need be).

The longest part of the job will probably be draining the water.

This is assuming it's not a sealed system or anythign like that.

Plumbing tends to be pretty easy, just never expect it to work first time round, or start a job on a day when the shops aren't open, or you're in a rush (Murphy dictates that if you don't have time to spend on it, then what should be a 15 minute job will take all day).

Ta, that's exactly what I needed to hear It is indeed a separate 3-way valve in the airing cupboard in a non-sealed system.

I may have to procure some length of hosepipe so I can drain the system directly into the bathroom, although before I do all of the above I may take the motorised head off and see if I can manually move the valve around and encourage it to start working again

Hi there,

I have no idea... I'd just like to say it might be sensible to get a CORGI pro involved if you need to poke around inside the boiler ;s.

(I'm a noob and no nothing about all this, so apologies if I'm very wrong).

There's no need to get an Engineer in unless you're actually poking around with the gas supply I've repaired blown boards in my boiler before now with no dire consequences!

That said, gas Engineers aren't Corgi registered now anyway I don't think. There's a new Gas register that has replaced it