Flow switch not activating Baxi Combi 80Eco

[nutty_jah]

Wonder if I could have some pointers with this boiler.

Flow switch is not being pushed out, with pump running. Pump rotation is strong (checked through the bleed screw), also taken out to check impeller which is securely attached.

When switch manually activated boiler kettles.

When flow and return valves isolated, pump pushes out rod to activate switch. Boiler obviously kettles.

I'm thinking it is a block main hex, any pointers? Thanks in advance. Nuran

 

[lame plumber]

diaphragm split but cant remember set up

 

[Alpha man]

Could be Blocked primary hex, and or primary flow pipe, check the DHW hex while you've got it drained down.

 

[jtsplumbing]

Are you in a hard water area ??

 

[nutty_jah]

Thanks guys, im back there on Monday so will check dhex and diaghpram.

@jtsplumbing. Yes it's a hard water area.

Now re dhex and split diaghpram. Dhex isn't in play is it if CH is called for. Unless div is stuck and trying to push through dhex.

And the diaghpram, suppose could be a split. Hence only activating when increased pressure when flow return closed.

Still doesn't explain the kettling when with pump running and switch manually activated.

 

[Billy Bob Bob]

Thanks guys, im back there on Monday so will check dhex and diaghpram.

@jtsplumbing. Yes it's a hard water area.

Now re dhex and split diaghpram. Dhex isn't in play is it if CH is called for. Unless div is stuck and trying to push through dhex.

And the diaghpram, suppose could be a split. Hence only activating when increased pressure when flow return closed.

Still doesn't explain the kettling when with pump running and switch manually activated.

either ch diaphragm has split ,the small one at the back,or the hole under its blocked get one of these in advance,you also need a stubby slot driver and a 8mm spanner Baxi Combi 105HE Central Heating Diaphragm Kit 5111138 NEW

 

[nutty_jah]

Thanks for the replies everyone, haven't been back yet. Job not authorized by agents yet!

 

[nutty_jah]

Thanks Gas Man, as you said. It was the blocked up hole under the diaphragm. The existing one was fine, although changed anyway.

 

[oily face]

Have you checked the filter on the return and the primary thermistor on the flow pipe from heat ex which is a wet pocket some times cap can get caught at this point

 

[lame plumber]

Have you checked the filter on the return and the primary thermistor on the flow pipe from heat ex which is a wet pocket some times cap can get caught at this point

have a gander at the post above yours, all fixed