honeywell v4073a only moving one way??

[scorpiouk]

Hi all,
After a bit of help, this is not my area! Came home today to found the house was cold. After some testing found it was the Honeywell v4073a Motorised Valve. (3 pot)

Was going to replace it, but after some testing not 100% sure its at fault, or suspect its gone in a strange way.

First made sure there is no call for HW or CH. I placed the valve in manual override. Pushing the leave I feel a nice level of resistance and can hear the motor turn as I push.

Then made a call for HW - I hear the value move back and the boiler click on. (there is resistance if I try move the leave back to override indicating it moved.)

Next I kill the call for water...

I make a call CH - There is no movement on the valve, the boiler remains off.

If I manually push the leaver to override, the boiler clicks and the heating comes on.. The heating operates normally with the rooms stat.

If then there is then a call for HW nothing changes. (HW+CH), I hear nothing form the valve.

When the CH ends, and the HW call is still active the valve move as mentioned above..

Its like the valve has 50% failed, e.g. it can move from CH to HW, but cant move back.. Is that possible?

I'm pretty sure its the value as I can get all bits of the system to work just by having the value in the various position.

Should I replace the powerheard or the complete valve?

Or I have I missed something..

Many thnaks

 

[seco services]

Change the motor.
Synchron motor

 

[scorpiouk]

Change the motor.
Synchron motor

Thanks for this..

Can it really fail one way only?

 

[matt1e]

Yes as it only motors one way
It returns to the hot water position under spring tension

 

[seco services]

In basic terms the motor only works one way to open the valve to hw/ch or just ch.
When only hw is called for the valve closes ch by a spring pulling it back to it's default position, not the motor.

The call for hw comes straight from the cyl stat, Call for ch comes from the orange on the valve.

 

[scorpiouk]

In basic terms the motor only works one way to open the valve to hw/ch or just ch.
When only hw is called for the valve closes ch by a spring pulling it back to it's default position, not the motor.

The call for hw comes straight from the cyl stat, Call for ch comes from the orange on the valve.

Thanks..

with mine set to CH... when the HW is called for I hear the motor move.. could it be the spring thats gone?

 

[matt1e]

If then there is then a call for HW nothing changes. (HW+CH), I hear nothing form the valve.

with mine set to CH... when the HW is called for I hear the motor move.. could it be the spring thats gone?

So which is it?

 

[scorpiouk]

If then there is then a call for HW nothing changes. (HW+CH), I hear nothing form the valve.

with mine set to CH... when the HW is called for I hear the motor move.. could it be the spring thats gone?

So which is it?

There is nothing when the timer is set for both.

If I manual move the leave to override the ch kicks in.
If I then make a call for hw I hear nothing

If its just hw the valve moves.