Hot rads when CH is off

[wadihalfa]

Hi Folks, This is my first posting so be gentle with me!

With the CH off, two upstairs rads get hot (just as hot as if the CH was on). Also, when the HW starts up in the morning, it sounds like air is gushing through the pipes in the airing cupboard and the two mentioned rads start to gurgle. Once the water has heated up (and I've bled the two rads, everything seems ok.

Am I right in thinking that it could be a problem with the 3-port valve sticking?

If God had wanted me to be a plumber he would have given me webbed feet!

 

[linkyplumb]

Sticking 3 port is more than likely the culprit.

 

[wadihalfa]

Can these things be 'unstuck' or is it a replacement job?
(Honeywell 40003916-003)
Can I assume its the 'wet' side of the valve not the electrical?

 

[kevplumb]

Can I assume its the 'wet' side of the valve not the electrical?

no

 

[wadihalfa]

I was speaking to a mate of mine in the pub last night. Apparently some plumbers connect bathroom rads to the HW side of things. Anyway, that seems to be what has happened here and is nothing to do with the 3-port valve. My mate is an electrician, I'm surprised you plumbers didn't think of that one!!
I've still got one more problem to sort out. Everytime the HW comes on it sounds like a surfacing submarine in the airing cupboard and I have to keep bleeding the two previously mentioned rads.
Could it be a blockage in the vent pipe? if so, what would be the best way to unblock it? I've just spent the last week or so de-sludging the system and putting in new inhibitor.