Faulty motorised diverter valve on Worcester Heatslave combi

[adyl]

Hi, I've got a Worcester 20/25 oil-fired storage combi boiler. It has gone faulty, in that although the central heating (sealed system) works fine, the domestic hot water runs cold.

I have checked the installation manual that came with the boiler. If I switch off the central heating at the controller and switch on the hot water, then open a hot water tap, the boiler's pump starts up, the burner fan starts and after a few seconds the burner starts too. Great, but the heat isn't coming out of the tap! It runs warm for about one second, then it runs absolutely cold.

I've had a look at the motorised head on the diverter valve. I think it's gone wrong because the lever won't spring to one side, and the lever itself feels quite loose. Might the spring have failed? The funny thing is that the installation manual quotes that 'The valve is powered open in response to demand from the central heating'... I have tried moving this loose lever to either side, but the hot water still won't flow to the taps.

If I need to replace the motor, do the spring/s come with it, or will I need to buy a new diverter valve as well?

Kind regards,

 

[adyl]

sorry to add something extra, but if I allow the boiler to heat up, switch off the hot water and central heating then open a hot water tap, the hot water should flow via the hot heat exchanger, with the pump running. The pump runs, but the hot tap still runs cold. Help!

 

[cider]

valve may be stuck in ch position. Dump the power to whole lot and listen to see if it travels back to hw position.
May sort it.
Boiler is hw priority and should always heat store (LH side) when hw stat is in demand even with ch on and no hw tap on

 

[adyl]

Thanks Cider,

When I power down boiler the valve lever doesn't move at all. I remember when it used to spring back to HW position but it won't move at all now on its own. The lever is loose-ish and can be moved to either position manually, where it just stays. However, no matter what position it's in, I can't get hot water to flow to taps.

If I switch off the central heating and put the hot water on, the pump, fan and burner kick in, but according to the rheostat for the hot water, the hot water never gets hot, despite the fact that the heat must be going somewhere, I think to the central heating. Eventually, despite the hot water rheostat not sensing the hot water getting to the selected temperature, the burner shuts off and the pump keeps running. A few minutes later the burner starts up again. I wonder, is this all caused by a faulty diverter valve head unit?

 

[oilman]

You'll have to take the control panel off, then take the head off and see if the valve spindle moves freely. If it does, then the Synchron motor in the head may need replacing.

 

[diy]

( I think to the central heating. )


have you checked the flow etc, are they getting hot, then the div would be the problem

 

[adyl]

Hi everyone, many thanks for your help. It's much appreciated. I've removed the control panel and lifted off the actuator. The spindle on the valve body moves freely about an eighth of a turn (which I guess is OK).

However, the problem is, I think, with the final gears underneath the synchron motor. The final pinion and quadrant have worn, and when I move the actuator's lever towards the manual position and let go, the teeth of the brass quadrant slip over the output pinion of the synchron motor in both directions, resulting in the output from the actuator failing to rotate with the springs towards the closed (HW) position. I can make the synchron motor' final pinion rotate by pushing on the brass toothed quadrant (so the motor is not seized), but wonder what I will need to replace. Will I need to buy a new complete actuator, or just the pinion and quadrant unit? If so, does anyone know the reference number for it? The actuator body has the Honeywell reference V4044F1109 on the end opposite the lever, and F4-9939 on the lever end.

Many thanks,

Adyl

 

[cider]

fitted one last week will cost ya cus it has a plug on the end of the lead
worc 87161201310 diverter valve assembly thats the valve complete but you just need to fit the actuator.

 

[oilman]

The gears often slip when the head is off the valve, but they are usually ok when the valve is assembled.

 

[adyl]

Thanks oilman. I've put the actuator back in position with its cover off. When I put the CH on the actuator moves across to open position, but when I switch off the CH the actuator only partially moves back towards the closed HW position. The valve body spindle can be turned with my fingers, so is the problem with stiffness in the motor / upper gearbox unit? If so, could I try spraying WD40 into the gearbox immediately underneath the motor?

Thanks.

 

[adyl]

With the actuator in position, the springs sometimes don't move the valve head at all towards the closed position, and sometimes only part way. The spindle in the valve body is easy to move by hand, so I can only assume it's the actuator assembly stiffening up. I've ordered a new assembly, including the valve body, as the price of the whole unit was only slightly more than the actuator on its own. The Synchron motor unit I have I think is OK, as I took it off the actuator body and I could turn the output pinion by hand, though it was quite stiff.

Thanks!