Central heating 3 way valve. Advice required please.

[B16 RFF]

I have a fully pumped system with a Honeywell V4073A 3 way valve controlling the flow to the hot water cylinder and the central heating. The problem I have is that the pump and boiler will not run unless the hot water side is calling for heat, no matter what I do to the central heating side. An ex-plumber friend has suggested the 3 way valve could be at fault. I have removed the cover of the valve's power head, and the motor is very hot (although valve body is cold), leading me to think something has jammed and the motor is overheating. I am able to move the lever from auto to open and back.
There seems to be very little rotation on the spindle of the actual valve, 45 deg or less. Is this correct, or is there a fault on the valve?

Thanks,

Paul.

[Wings]

My oil central heating and hot water system has two Honeywell valves, that recently due to the age of the system, could not be repaired, but had to be replaced.

I had the same fault on my system that you have posted, and I submitted an e-mail to Honeywell, http://www.honeywelluk.com/ , receiving a telephone reply within 2 hours from a technician.

As I indicated above, recent manufactured valves can be repaired, with parts readily available from their local listed stockiest.

[GreenDog]

We moved into our house in July and it was apparent early on that there was a problem with the CH as when the HW was on the rads would warm up too. I'd experienced probelms like this in previous house so suspected the 3-way valve was a fault, which was confirmed by the 2nd plumber, the 1st didn't bother to even turn up or ring to say he wasn't coming ! £90 and about 20 minutes work and the valve and actuator were replaced.

[Simpo Two]

GreenDog said:

We moved into our house in July and it was apparent early on that there was a problem with the CH as when the HW was on the rads would warm up too.

I had this too, but dealt with it simply by turning the rads off in summer. When the HW cylinder was replaced I got the man to fit a new valve - and then I realised my nice warm towel rail was no longer warm

[Dogwatch]

B16 RFF said:

I have a fully pumped system with a Honeywell V4073A 3 way valve controlling the flow to the hot water cylinder and the central heating. The problem I have is that the pump and boiler will not run unless the hot water side is calling for heat, no matter what I do to the central heating side. An ex-plumber friend has suggested the 3 way valve could be at fault. I have removed the cover of the valve's power head, and the motor is very hot (although valve body is cold), leading me to think something has jammed and the motor is overheating. I am able to move the lever from auto to open and back.
There seems to be very little rotation on the spindle of the actual valve, 45 deg or less. Is this correct, or is there a fault on the valve?

Thanks,

Paul.

I would agree with your conclusion. If the motor is hot when the rest of the unit is cold then there is certainly something jammed. Contact Honeywell as suggested, though if the unit has to be replaced that's probably a drain down and refill.

[Arthur Jackson]

Sounds about right for the angle of movement. I reckon one of the microswitches has gone. The motor does get warm when it's stalled.

[B16 RFF]

Thanks for your replies. I have bitten the bullet and replaced the actuator unit, and all seems to be ok now. On closer examination of the old unit, it looks like one of the microswitches is faulty.

Cheers,

Paul.