Y plan dilema....

[banditboy]

hi guys i was pottering around in our airing cupboard,[wine making ]

and noticed that there is a slight buzzing from the 3 way valve....
its been fitted for 10 yrs +
this is when the heating and water is off, honeywell time clock,

i used to wire y plan systems 20 yrs ago in a former life as a sparky,and prob have some schemes somewhere,
id imagine that the valve should not be energised, in an off period,so there is a cross over in the junction box in the airing cupboard,

the valve is not in the midway position , but over to the hot water port,

all is working well...for as long as we have been here...
i await your thoughts.....

 

[Agile]

The motor is energised and stalled when its off.

Thats normal and many do buzz.

If you fitted a new motor then it might be quieter but better to wait until it fails.

Tony

 

[banditboy]

thanks for the quick reply,tony,
it is very quiet,and prob has always been,i have to be right next to it
i did change the pump a few years ago and never noticed it,
i just thought it would be at rest, without power when not working..

 

[MANDATE]

The motor is energised and stalled when its off.

Your reply had me stumped for a minute. banditboy did say it was over to the HW port, but maybe he got that bit wrong
In CH position the room stat will remove the power to ignite boiler, but motor is still energised and up against a stop.
In Mid position the motor is energised and stalled.
In the HW position however the motor has no power from room stat so cannot be energised.

 

[oilhead]

With the clock off for both heating, if the last demand was for heating, then the valve will stay in the heating position, stalled against the port until the switch tells it to do something else. Many current programmers incorporate a 'de-latching' switch to stop this when there is no programmed event.
When there is a CH and DHW demand, the valve oscillates in the mid position and can sometimes be heard switching on and off

 

[MANDATE]

When there is a CH and DHW demand, the valve oscillates in the mid position and can sometimes be heard switching on and off

If that happens, then its not normal in my opinion.
My belief is that when the first micro switch is triggered (and the 'grey wire' is not 'live') the 230v supplied by the 'white wire' is dropped but the modified voltage supplied by the pcb still remains and holds the valve in equalibrium against the return spring. If at this stage the valve drops back and contact is made again with the 'white contact' and it keeps repeating this action, then surely this a fault related to the pcb.
To continually make and break the contacts every second or so would not be intended and would soon lead to micro switch failure.

 

[D_Hailsham]

banditboy did say it was over to the HW port, but maybe he got that bit wrong

Probably going by the visual position of the lever - not a reliable indication of valve position. If the lever is loose then the valve is in CH or CH+HW position. If the lever is stiff, the valve is in HW position.