Baxi making regular noise after power down

[fixitflav]

I don't know if a diverter motor should keep running, 24/7

No, it shouldn't. Depending on what's calling, when it reaches the end of its travel it stalls. The motor is designed to take it. Sounds like there's something wrong with yours.
Edit - ignore most of that, I was thinking of Y-plan with external diverter valve. But I still don't think it should be running continuously.

 

[rt18]

No, it shouldn't. Depending on what's calling, when it reaches the end of its travel it stalls. The motor is designed to take it. Sounds like there's something wrong with yours.
Edit - ignore most of that, I was thinking of Y-plan with external diverter valve. But I still don't think it should be running continuously.

I've just bought a Baxi genuine part from Screwfix, have it in my hands now but can't try installing it until later. I'll report on what happens.

I assume the driver motor sits on top of the valve, and isn't exposed to water, so I don't need to drain the system to replace the drive.

 

[rt18]

This is a fantastic video from Baxi on the diverter motor body workings!

I watched this video to learn how to replacer the diverter head, and the chap mentioned water showing in the head would mean the diverter cartridge had failed. I've got exactly that, water in the head and evidence of rust on the retaining clip. I'm now ordering a replacement cartridge for the diverter body.

Someone commented there's a theory that inhibitor fluid is perhaps causing the seals to fail...

 

[fixitflav]

I've just bought a Baxi genuine part

Is it this This?

I assume the driver motor sits on top of the valve, and isn't exposed to water, so I don't need to drain the system to replace the drive.

Unless the valve is leaking, like he said in the video, in which case it needs replacing.

 

[rt18]

Is it this This?

Unless the valve is leaking, like he said in the video, in which case it needs replacing.

Yes, that's the part. But i've just discovered the diverter is leaking. So I need a replacement diverter cartridge too. Ordered from Screwfix, will collect then fit. I'll report back...

 

[fixitflav]

Yes, that's the part. But i've just discovered the diverter is leaking. So I need a replacement diverter cartridge too. Ordered from Screwfix, will collect then fit. I'll report back...

So I suppose you need to drain, at least partly. Unless you have iso valves in appropriate places, it might be worth isolating (both ends) the rads above boiler level.

 

[rt18]

OK, so I got this solved.
When I took off diverter motor I discovered water, which meant the diverter valve itself was leaking upwards into the drive. New drive and new diverter valve cartridge (thankfully not a diverter body replacement).
To replace (for reference in case anyone's interested), these are the steps I took:
1. Isolate electric and gas to boiler (technically the part is a water part, no gas parts were touched)
2. Isolate all inlet and outlet lines (CH in and out, cold water in)
3. Run the DHW tap until pressure drops.
4. Remove the diverter drive (remove clip, drive lifts off)
5. Unscrew the diverter valve cartridge from the top of the valve body and extract (I had a continuous slow water leak from the top of the exposed valve body - I don't think my isolator valve is entirely working)
6. Reverse the above to insert new valve cartridge and assembly drive motor.
7. Dry the system (kitchen paper), then replenish lost pressure in the CH by topping it up.

I tested it with CH and DHW separately, and now the valve drive works as expected. It moves silently, from one end to the other, with a satisfying little click at each end and no further movement.

Also, I tested the old drive terminals for resistance and there was Open Circuit across all pins, which meant it was knackered. The water must have damaged it, so I'm surprised it worked at all.

 

[fixitflav]

Well done!