CH/HW System Problems - Poss Dodgy 3port valve & pump

[Jamieboy]

Having had a couple of issues over the last few days i have a couple of questions.

Now the weather has gone to nice & warm i've turned my CH off, but the rads still heat up.

Is this because the 3port valve rotates constantly? Its a blue switchmaster valve,

Also my pump doesn't appear to work, theres valves either side of it, is it an easy fix or something i should get someone in to do? I have a healthy DIY knowledge, but my main knowledge is with electrical, so I'm happy to attempt this job if its not too hard.

Many thanks in advance

 

[gas4you]

If the pump is not working, then how are the rads getting hot?

I would check the 3 port and possibly change this before looking at the pump as well.

 

[Jamieboy]

Cool. Is this a normal sounding operation for the valve to continually turn whilst set to CH?

If the valve has had it what is a suitable replacement actuator for it as I can't seem to find new Switchmaster units? Existing unit is a MIDI VA1, so my original thoughts were incorrect - it is a mid-position valve

 

[alan8376]

Switch off boiler. Wait until all the pipes have cooled first.

Restart the boiler, then try moving the manual lever at the side of the 3 port valve and holding it across in the other direction.

If the pipe to the Rads stays cool you have found the the problem!

Now you need to see if the electrics move the mechanical bits. If they do! Then the mechanical parts internally are stuck!

 

[Jamieboy]

Not quite the answer i was after. The valve doesn't stick, it turns constantly. is this a normal behaviour? Forgot to mention, it turns really slowly as well, can see this from the white slot head on the top of the valve motor casing.

 

[gas4you]

Don't know this particular valve, but unless it is a MOMO type valve, then it should stop when whatever position is requested is reached.

 

[petit_pablo]

Had a sunvic MOMO valve spinning constantly. Replaced the head and all was ok, evidently something had broken inside.

I believe the switchmaster valves are now obsolete so you will need to change bothe head and body.