Vibrating/rattling V4073A mid position valve

[kevt296]

Hi all central heating experts. Can I pick your brains please?

Central Heating programmer recently changed from Switchmaster 400 to Danfoss FP715si. As far as I am aware the main difference between the two is that the Danfoss allows individual control of HW via the HW off signal missing not used on the Switchmaster

Since the change I notice that when HW and CH are both on, the mid position valve buzzes/rattles/vibrates (cannot really describe the noise). Once HW achieves set temp and I guess, shuts off, the noise stops.

I assume that with the Switchmaster it wasn't present cos both HW and CH were not independent but wonder if the valve is perhaps so old that now it does work independently, the valve does not like the change?

Can anyone advise cause of problem? Could it be simply replaced or is it a wiring or voltage/current issue? I have checked the wiring (Y plan) and it all seems to be correct, the system is operating correctly. Obviously do not want to purchase new and then find prob is still there.

Also any ideas on best place to obtain replacement other than Ebay?
Or can you suggest an alternative to the Honeywell?

Many thanks plumb people, I would appreciate your help!

Cheers

 

[45yearsagasman]

Do you hear the noise when only the hot water is selected? Honeywell valves are usually very reliable.If it only makes the noise in mid position then it may be a mechanical failure and you can change the powerhead.If your valve has a raised dimple on the silver cover then it's replaceable.

 

[kevt296]

Hi 45yearsagasman

Many thanks for the advice, sorry for the delay in replying.

It does only occur when hot water on.

It does have the dimple, Any ideas where to get the powerhead from?
Thanks again

 

[45yearsagasman]

Obtainable from any decent supliers...Plumbcentre, PTS etc. As it occurs with HW on and heating off I'm not 100% sure that the head is your problem.The valve motor is under no power when in HW only position.