Baxi Combi 80 eco Flow switch

[Blake]

Hey all,

Been out to one of these this eve and practically stripped it to bits but could not get it working.

Basically, when there is a demand for CH the flow switch is not being activated. The pump runs and I can push the microswitch tab up which makes it fire up but the pin on the div valve is not actuating.

Another engineer has been out and replaced PCB, APS and also a new diaphram on the flow switch (no idea why PCB and APS where changed).

There is some dirt in the system, but nothing major and I've seen far worse. The Fault finding section states the Flow Valve rod is obstructed.

I've no idea where this Flow valve rod is located as it's not in any diagrams in the manual and I was running out of time to keep hunting for it.

So, how do I get to this part or should I just just put a new div valve on?

Is there anything else that would stop the flow switch from actuating?

I'm knackered, my head has gone to mush and I've missed most of the footy

Cheers

 

[Toddyplumb]

Diaphragm out, little hole in brass housing , clean out little bit o dirt with pin, replace diaphragm. Good as new £30

 

[Blake]

I removed the Diaphragm and saw the little hole in the brass body, but did not even think to try and put something in there to try and clean it, Ruddy hell. So what's this rod the manual mentions then?

 

[Toddyplumb]

The rod is pushed by the diaphragm , they sometimes stick, gives the same result as the hole blocked

 

[Billy Bob Bob]

Diaphragm out, little hole in brass housing , clean out little bit o dirt with pin, replace diaphragm. Good as new £30

quite right,had this on a new performa,gunk in the brass hole must have been in stock for a while

 

[Poxi]

Also Blocked main heat exchanger will give this fault..When you left the microswitch and the boiler fires is it noisy..

 

[Billy Bob Bob]

Also Blocked main heat exchanger will give this fault..When you left the microswitch and the boiler fires is it noisy..

yes it will so will a knackered pump,but the small brass hole is prone to system debris

 

[Blake]

Well I know the rod aint stuck as its just been replaced. I did not let the boiler run long enough to know if it was noisy when I manually lifted the micro switch.

So to clarify, after removing diaphragm, I need to put a pin down the small hole in the brass body that the diaphragm sits on?

I checked the pump and it spins freely and I can also feel the water vibrating in the flow and return pipes from the heat exchanger.

The flow switch just does not operate.

 

[Billy Bob Bob]

Well I know the rod aint stuck as its just been replaced. I did not let the boiler run long enough to know if it was noisy when I manually lifted the micro switch.

hmm, so div valve or blocked heat exchanger then???

clean out the brass hole under flow switch diaphragm first easy job may not need parts,use silicone grease on re assembly of rod pin