boiler

[shocking]

Re Brittany combi SE
Hi
Can you give me some idea what will cause heating not to respond after initial firing?

What I have noticed is that the boiler first fires up, then shuts down, the fan keeps running but the burner will not relight.

 

[Rob]

diverter valve from your brief descrption. Giving it a wack will get it going temp. until you can find a boiler engineer desperate enough to want to change one.

Not a nice job. Im assuming the HW is ok?

 

[shocking]

Thank you for your reply rob884

If this makes know difference what else will possibly be the cause, My thoughts on this are that the upper heat censer is sticking as the pump is also running.
Yes the hot water is fine

 

[corgiman]

do they have that good awful filter on the return like the old one?

 

[shocking]

Good? I have no idea to that without first looking

 

[Rob]

Both CH and HW are controlled by one thermistor, the other is fairly usless.

We are talking about a C-M britony combi 80, yes?

Not alot more i can tell you really. except feel the flow pipe inside the boiler when its hot. This heat, when heatings on, should obviously be diverted down the htg flow pipe.

 

[kevplumb]

do they have that good awful filter on the return like the old one?

yup

 

[shocking]

Rob if CM stands for chaffoteaux & maury then your right on the ball

 

[Slugbabydotcom]

Flame sensing
Thermistor
Gas valve soleniod not opening properly
Low gas pressure
APS
APS tube/s
Blocked venturi
Weak fan
etc etc

 

[shocking]

kevplumb
ho dear!
You.ve put my nerves on edge

 

[corgiman]

OMG dad they are a nightmare

strip it down and clean it. a pound will get you a pinch of snuff thats the problem

good luck I hate chaffs big old heaps off poo that have been farmed out to an agency MTS

Sheesh

 

[shocking]

Rob
Is your description of the diverter valve the central heating control thermistor or the three way valve?

 

[Rob]

three way valve, as i said a tap might free it up. but your problem could also be a blocked filter as corgiman has said.

 

[shocking]

Rob the fault seams to occur when the hot tap is used this shuts down the heating when the tap is turned on and of again the heating comes back on

 

[Slugbabydotcom]

Rob the fault seams to occur when the hot tap is used this shuts down the heating when the tap is turned on and of again the heating comes back on

Now you have told us something that could give us an inkling.
It's still a bit of a guess cos I can't see it but what goes on these often is the flow switches. In this case I think that your hot water flow switch could be sticky.

Here's the scenario I have in my mind

Heating is on.

You turn hot water on

Hot water demand is satisfied when you turn the tap off but instead of shutting off by the HW flow switch it shuts off by the thermistor as the flow switch is stuck on.

Boiler will not go back to CH until you turn the tap on and off sharply to free the sticky HW flow switch.