Honeywell V4073A 3 position valve - powerhead problem

[dansaund]

Hi,

Has anyone else seen a problem with new V4073A units recently? My initial fault was a seized valve, and so I replaced the whole valve. After that, intermittently the boiler would not fire for CH, and I noticed that if i touch the manual release valve on the powerhead, the boiler fires straight away. Honeywell sent me a replacement powerhead FOC, which has the same fault. I had a look inside today, and there are two brass lugs that activate the two microswitches inside. The shorter one does not always activate the microswitch which triggers the boiler to fire. Seems to be a manufacturing fault - there is too much play in the mechanism and so the brass lug is an an angle, so not quite close enough to activate the switch. Anyone else noticed this fault?

 

[gaspro1981]

No not had any failures myself

 

[Agile]

Did you replace the whole valve or just the motor head?

Are you tightening the two screws equally a little at a time?

Tony

 

[dansaund]

Did you replace the whole valve or just the motor head?

Are you tightening the two screws equally a little at a time?

Tony

Tony - First I had the whole valve replaced by a plumber, I replaced the powerhead myself and yes tightened the screws equally little at a time. The problem seems to be that the switch 2 inside is not triggered by the brass mechanism inside.

 

[twgas]

Is it failing to fire when the HW is turned off at programmer or when the cyl stat is satisfied?

 

[dansaund]

Is it failing to fire when the HW is turned off at programmer or when the cyl stat is satisfied?

Hi Twgas

Fails to fire more often when HW off at programmer, but also sometimes when cyl stat is satisfied. Almost guaranteed to fail To fire CH when HW is off as programmer, maybe 1 or 2 times per week fails when cyl stat is satisfied. Always fires as soon as I touch the manual lever, which is why I suspected the micro switch which controls the orange wire.

 

[twgas]

I think i would check the valve body, make sure the spindle is free as you've had the same problem with 2 powerheads.

 

[dansaund]

I think i would check the valve body, make sure the spindle is free as you've had the same problem with 2 powerheads.

Spindle moves freely, I checked this today. It can easily be moved by hand. The mechanism inside both power heads does not activate switch 2 which outputs to the orange wire, that in turn outputs to the boiler.