Worcester Combi 20/25 Oil Boiler - Central Heating Pump

[RJA67]

On heating only, it sounds like you are pumping against a closed valve. If you are getting a cool shower and hot radiators, then something is opening the valve when you want hot water only. From 1998, the original actuators were changed, and if you have replaced the actuator, then the wiring may not be compatible. From memory, a small change was required, so check your wiring at the PCB.

I've only changed the actuator motor, but more than a dozen times! Only two wires, so no issues there. Just found out the delivery on my CH stat is going to be 10 days. I didn't need it when I ordered it, but was going to change it anyway due to it's course feel. Then it gave way on me, so I really need it now! So I'm going to have to travel get one today, an hour each way. Going to pick up a diverter valve as well, to have just in case. After that, it can only be the PCB. It looks ok, but haven't taken it out for closer inspection.

 

[Gasguru]

Sounds like you're fitting knock-off motors.
The only easily available genuine synchron motors are the bagged Drayton motors from Screwfix.

 

[RJA67]

All the motors I've fitted have been from a reputable dealer, up until the one that's in just now. For easiness at the time, I got that one from eBay. It is slightly different, but only where the cable enters the body. It is working fine, motoring when asked. I'm just back home from getting the CH stat and diverter valve, so I'll be fitting the stat very shortly.

 

[Gasguru]

Trust me there are no reputable dealers, even merchants I've known for 25 years are now routinely selling copy boiler spares etc and passing them off as genuine.

These are the genuine motors....
https://www.hansen-motor.com/products/ac-synchronous-motors/600Series-K-mount/

 

[RJA67]

Thanks Gasguru. I will look those up next time. Maybe those will last a bit longer!

That's the CH stat now replaced, but I'm not going to comment yet.......

 

[oilhead]

Genuine Synchron motors have the name stamped in the cover. Reputable stockists do sell cheaper versions, but I've yet to see one passed off as genuine. They sell cheap ones to satisfy the cheapskate repairers who look for the last extra ponds of profit they can screw out of unsuspecting customers.

 

[RJA67]

Update: I have just changed out the diverter valve. On removing the old one, I could see that the ball had become dislodged, which Terrywookfit had suggested. It was rattling around inside the chamber like a malteser . I had a plumber mate around to help me get the valve out, as it was solid. He said that he had never seen the ball dislodge before.

Thank you all for all your advice over these last few days

 

[Gasguru]

You've been unlucky there...I've only seen it a few times in 20 years..glad you sorted it.

 

[snb]

genuine syncron motors have stamped syncron on the top. the copy versions have stamped syncronous. genuine should last about 6 to 8 years. copies will last about 2 to 3 years.

you could have just undo the 4 screws and replaced the plate with the ball. much easier

 

[RJA67]

You've been unlucky there...I've only seen it a few times in 20 years..glad you sorted it.

Thanks Gasguru.

 

[RJA67]

genuine syncron motors have stamped syncron on the top. the copy versions have stamped syncronous. genuine should last about 6 to 8 years. copies will last about 2 to 3 years.

you could have just undo the 4 screws and replaced the plate with the ball. much easier

I'll keep an eye out for those markings in future. I had one last just a week once!

Yes, with hindsight I could've done that, but I took the valve out before I knew that was the problem. Although more work, I think it was better to replace the whole unit after 23 years of service. I might refurbish the original, but hopefully I will never need it again.