"Thump" when the CH Hot Water is turned on - Help

[seco services]

should be a spring even if its fell off.
the springs in the actuator not the valve body.

if your old valve body is getting crudded up the spring may not be strong enough to pull the valve to hw position. and the water is forcing it to hw position so then it thumps.

 

[macketty]

Follow that, Karl.
I was worried I was needing another new motorised head, but from what you're saying I should have replace both parts last year rather than just the motorised head - or have I knackered the head now I wonder. I only changed the head, as the motor had failed and the valve still seemed free-moving.
I suppose there's nothing for it but to replace the valve body tomorrow and see what difference it makes.

Mac.

 

[seco services]

being as you already have the body you have nothing to loose.
if then it still happens then need to look at the actuator.

but check the actuator when you remove it or even with it on the body still,
if you isolate the mains power to your heating system the actuator will fall to its relaxed position HW open HEATING closed.
the lever on the end will have resistance on it if you push it across and let go you can hear/see the valve return to HW only position by the spring pulling it back.

if you remove the lid you'll see what i mean.

 

[macketty]

Thanks for all your help Karl. I'll give it a go tomorrow.

Mac.

 

[doitall]

Just in case you need confirmation.

The ball in the valve is loose.

 

[seco services]

Just in case you need confirmation.

The ball in the valve is loose.

oh you turned up then.

 

[doitall]

Just in case you need confirmation.

The ball in the valve is loose.

oh you turned up then.

Been at a meeting till 22:30.

 

[macketty]

Thanks to all, in particular Karl for all your help.

Got the job done today and hey presto: No thump!

Had a look at the old valve - couldn't see a thing wrong. Obviously it must have worn in the last 19 years and I suppose the tolerances are such that imperceptible (to an oaf like me) differences from new, in the apertures and ball are enough to make the house-ringing thump.

Mopped-up all the water (god knows where it all came from) and have just about got all the floor boards back.

Thanks again for all the help offered to a first-timer on the forum.

Mac.

 

[doitall]

Thanks again for all the help offered to a first-timer on the forum.

A pleasure, glad you got it sorted, and thanks for the feedback.

 

[seco services]

Thanks again for all the help offered to a first-timer on the forum.

A pleasure, glad you got it sorted, and thanks for the feedback.

i'll second that.