Baxi 80E Combi boiler

[picasso]

Then there is nothing wrong with the pump proving switch you will probably find the plate heat exchanger is blocked or the boiler isint recognising the hot water demand.

 

[jeddyboy]

Then there is nothing wrong with the pump proving switch you will probably find the plate heat exchanger is blocked or the boiler isint recognising the hot water demand.

There is if i do not push the pin in i get nothing..Boiler will not fire up
for either cent heating or hot water.

 

[ChrisR]

yes central heating works ok, but if i do not push the pin manually do not get any hot water because boiler will not fire up.

SO that was wrong, then...


What pin are you pushing? The pin is operated by the diaphragm. The switch doesn't have a pin.
The pin presses aginst a lever iirc, which operates the switch which has a small plastic bit sticking out under the lever.
If you mean the pin isn't coming out far enough to operate the switch, then there could be several reasons for that.
How far is it moving and, is it the same for CH as HW? (As asked before)

 

[jeddyboy]

yes central heating works ok, but if i do not push the pin manually do not get any hot water because boiler will not fire up.

SO that was wrong, then...


What pin are you pushing? The pin is operated by the diaphragm. The switch doesn't have a pin.
The pin presses aginst a lever iirc, which operates the switch which has a small plastic bit sticking out under the lever.
If you mean the pin isn't coming out far enough to operate the switch, then there could be several reasons for that.
How far is it moving and, is it the same for CH as HW? (As asked before)

correct the pin is not coming out far enough to operate the switch,
the other is working fine, as long as i push in this pin on ch valve it works ok.

 

[jeddyboy]

and boiler will fire up for either hot water or ch.

 

[jeddyboy]

Any help appreciated guys, So far the problem is with pump proving switch,
the pin is not coming out far enough to touch the microswitch,

To get the boiler to fire up i am manually pressing in pin/plunger to make the boiler fire up, i have ordered the small diaphragm replacement, but what is the best way to drain boiler in order for me to fit new diaphragm. thanks

 

[Gasguru]

9 times out of 10 there will NOT be a problem with the differential pressure switch assembly...it is probably functioning fine.

The switch operates when a sufficient differential pressure exists across the diaphragm to lift the pin. The inlet side of the pump is connected to the top side of the diaphragm. The outlet (flow) of the primary heat exchanger is connected to the lower side of the diaphragm. There must be sufficient water flow around the primary system to create a sufficient difference in pressure across the pump and primary heat exchanger.

This fault is rarely easy to solve....

Could be....

Trapped air
Flat expansion vessel
Weak pump
Blocked pump impeller
Blocked plate heat exchanger
Blocked pipework
Debris buildup on fibre washer connections
Blocked primary heat exchanger
etc etc

Start with the pump but if you're struggling with draining then this fault is probably not one to tackle.

 

[jeddyboy]

many thanks for your quick reply,
could it just be the pin/plunger being fouled/dirty or the smaller diaphragm not working correctly? would it be safe for me to fit these parts without draining boiler thanks.

 

[Gasguru]

As I said 9 times out of 10 there is nothing wrong with the assembly, yes sometimes the diaphragm is weak, perforating, pin sticking etc.

Yes you have to drain the boiler. Get someone in...you're gonna create more problems if you're not careful.

 

[jeddyboy]

okay thank you, just to add i purchased some black swan silicone few days ago and lubricated a small part of the pin/plunger

just had look again at boiler blow me down the pin is now coming right out and touching microswitch,fingers crossed might be ok..
Thank you for your time and answers, and yes i will not touch the boiler,
regards jeddyboy.