Honeywell Motorized Valve Buzzing

[richchad]

I have a Honeywell Motorized Valve for the hot water and recently it has been buzzing, quite loud some days but not always.
It is a sort of resonating sound so not sure if okay to leave it or replace it.
Here is a photo of the valve, maybe someonw will know if it part of it can be replaced without draining down?
The valve must be over 25 years old if that helps...

 

[stem]

It has a synchronous motor inside and when they get old and worn they do buzz.

The motor can be replaced. See here. But if the motor is worn so will be the rest of it, so usually it's best to change the whole powerhead. See here. Neither replacements will require draining down.

Other suppliers of the parts are available

 

[richchad]

Would this one be okay, Link it is a complete valve but assume I could just replace the body?
The detail on the label looks the same as the old one and seems to be a bit cheaper even with postage.

 

[stem]

I'm going to say yes, because both power heads both show the same part number as you can see below.

The 'bump' on the top of the lid indicates that the powerhead is replaceable. The original ones weren't.

However, according to the diagram on the old powerhead it has a SPDT switch with a white wire. This is optional and from your other photos the new powerhead only has the orange and grey wires. It is quite likely that the white wire isn't used with your system, but it would be worth checking first to be sure.

 

[richchad]

@stem, thanks for your help, will check out the connections before I order any valves.

 

[richchad]

I have finally got round to looking at the wiring connections to my Hot water valve, I can see the 3 wires connected to the switch, orange, grey and white.
According to the diagram shown above on the valve cover I can just make out the Grey is N/O and the White is N/C so assume the orange is Common.
As I don't know if the white cable is connected at the other end to anything maybe I should just change the motor and leave the switching as it is?
If I do change the complete head is the switch the same as in this photo of the wiring, I can't see how the are connected are they just push in type as can't see any screws?

 

[Exedon]

A new head comes complete with its own already connected cable just switch over in junction box.

 

[richchad]

A new head comes complete with its own already connected cable just switch over in junction box.

Thanks Exedon, does it state what each colour wire is connected to in the valve or maybe I have to just open to check connections?

 

[Exedon]

No need to check just follow what's there if new head has white wire make it electrically safe.

 

[stem]

I can see the 3 wires connected to the switch, orange, grey and white.......I don't know if the white cable is connected at the other end

If the white wire from the existing head is used, the new head will also need a white wire. However, the powerhead you originally showed as a proposed replacement doesn't.

These days it's very rare for the white wire of a two port valve to be used, hence why the vast majority of new powerheads don't have one. The white wire was used with what was known as a 'C Plan' an old system where the hot water cylinder was heated by natural gravity circulation and the pump was just for the central heating.

The usual pointer for a 'C Plan' is that there is only one motorised valve controlling the hot water, and the central heating doesn't have one. If you have two motorised valves, one for hot water and one for central heating that would point to it being an "S-Plan" and they don't need the white wire. But the best way to check is to find what is on the other end of the existing white wire.

 

[richchad]

If the white wire from the existing head is used, the new head will also need a white wire. However, the powerhead you originally showed as a proposed replacement doesn't.

These days it's very rare for the white wire of a two port valve to be used, hence why the vast majority of new powerheads don't have one. The white wire was used with what was known as a 'C Plan' an old system where the hot water cylinder was heated by natural gravity circulation and the pump was just for the central heating.

The usual pointer for a 'C Plan' is that there is only one motorised valve controlling the hot water, and the central heating doesn't have a motorised valve. If you have two motorised valves, one for hot water and one for central heating that would point to an "S-Plan" and they don't need the white wire. But the best way to check is to find what is on the other end of the existing white wire.

My system is about 25 years old and is a Megaflow sealed system and have just found the other end of the cable coming from the valve and the white wire has been cut off flush with outer sheathing, so looks like white wire isn't needed.
So I assume I can get the replacement head in your Screwfix link and just make same connections as Exedon suggests.

 

[richchad]

Update
Bought the replacement head this morning from Screwfix, fitted this afternoon, a bit of stress when I thought it wasn't working then realised tank was already hot and not calling for heat, turned tank thermostat up a touch and all looks okay, couldn't hear any buzzing so hopefully will be okay for a while.
@stem @Exedon - Thanks for all your help.