Any boiler experts?

[All that jazz]

Hi, I have a Britony II T boiler and it won't ignite unless the hot tap is nearly fully open. But even with the hot tap fully open, if I then open the cold tap at all, the igniter goes out and I then get cold water out of both taps . The ignition control knob is fully open to the right and the water inlet tap is fully open. It's been suggested to me that the diaphragm and/or thermocoupling may be broken and need replacing. Are there any boiler experts here that can advise and also tell me what the diaphragm and thermocouplings do please?

[silversurfer1]

I used to repair loads and loads of these, i would say you have two issues both very common firstly the pilot injector is partially blocked causing a small pilot flame, when the main burner does light the pull of main flame lifts the small pilot flame, it goes out and then the vale shuts down. Could also be a thermocouple issue but i very much doubt it as i replaced very few on the britoney but they always had a blocked injector.

Second issue would be a diaphragm stretched or has a hole in it.

The pilot (small flame) burns around the thermocouple, the heat is turned into voltage by the thermocouple which is sensed by the gas valve keeping it open, if the pilot goes out the voltage is stopped and the gas valve shuts down.

The diaphragm sits in a brass housing as you open a hot tap water runs under neath it, it then pushes a plunger up that is connected to the gas valve and opens the main burner giving you hot water.

Both are an easy fix on that unit 1hr max and the diaphragm is still available as a spare part.

Good luck

ss

[All that jazz]

silversurfer1 said:

I used to repair loads and loads of these, i would say you have two issues both very common firstly the pilot injector is partially blocked causing a small pilot flame, when the main burner does light the pull of main flame lifts the small pilot flame, it goes out and then the vale shuts down. Could also be a thermocouple issue but i very much doubt it as i replaced very few on the britoney but they always had a blocked injector.

Second issue would be a diaphragm stretched or has a hole in it.

The pilot (small flame) burns around the thermocouple, the heat is turned into voltage by the thermocouple which is sensed by the gas valve keeping it open, if the pilot goes out the voltage is stopped and the gas valve shuts down.

The diaphragm sits in a brass housing as you open a hot tap water runs under neath it, it then pushes a plunger up that is connected to the gas valve and opens the main burner giving you hot water.

Both are an easy fix on that unit 1hr max and the diaphragm is still available as a spare part.

Good luck

ss

Thanks SS. Can't really visualise the workings of the diaphragm from your description so I'll take your word for it. Would you able to tell if the pilot was partially blocked if I provided a pic of the flame from the front?

[silversurfer1]

No that would be difficult on that unit you need to remove the cover to get a decent look but id be certain thats your issue

ss

[burritoNinja]

I had a problem similar on our combi boiler. If it were set to just have the heating turn on, it would not but would fire up if we ran the hot water. In our case we had a new PCB installed. I think there were also pressure issues. We were topping the pressure up every few days.