How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Andrew Smith Your Own Question
Andrew Smith
Andrew Smith, Engineer
Category: UK Plumbing
Satisfied Customers: 3629
Experience:  Domestic Gas, Commercial Gas, LPG, Unvented Hot Water, Part P Electrical, Commercial Catering
Type Your UK Plumbing Question Here...
Andrew Smith is online now
A new question is answered every 9 seconds

My boiler isn't working

Customer Question

Hi, my boiler isn't working
Submitted: 1 year ago.
Category: UK Plumbing
Customer: replied 1 year ago.
No pilot, no ignition. Tried on and off. Water pressure was also zero. Topped that back up. Currently sitting on 2 bar( maybe that's too high??) followed some YouTube videos that advised on changing the thermocouple, I did this and everything worked. Left it on for 20 minutes. Tried again in the evening and it's back not working.
Customer: replied 1 year ago.
I also hovered out some of the mess build up.
Expert:  Andrew Smith replied 1 year ago.

Do you have the make and model? if the thermocouple does not go directly into the rear of the gas valve you may find it goes through an overheat stat that may be faulty

Customer: replied 1 year ago.
Hi, it's a vokera 12-48 mynute..........the thermocouple that I replaced just sat in a housing inside the main body of the boiler.
Expert:  Andrew Smith replied 1 year ago.

But where did the other end connect to?

Do you have the GC No.?

Customer: replied 1 year ago.
Is GC gas catagory? If so then 1N.The thermocouple at the probe end is located onto a small pocket on the hot water out pipe in the main boiler compartment, the other end is two wires coming off the spade terminals, 1 going to a electrical connector block which if I follow goes into another 6 way electrical connector, six way with 4 wires going in. The circuit drawing beside it looks to me that it's a switch for a motor. The second wire from the thermocouple connects onto a 2 way connection on the hot water pipe on the lower section of the boiler with the other wire from that connection going to the thermostat knob.
Expert:  Andrew Smith replied 1 year ago.

Ok, that's not the thermocouple - it sounds like the thermostat.

The thermocouple sits in the flame.

The GC no. Is on the data badge is is in the form of XXX-XX-XXX

Customer: replied 1 year ago.
Ok, it looks like there is no thermocouple. The only things in the flame compartment are the ignitions, one at either side with the wires from each leading down to the PCB compartment. So what gives the system the signal to let out gas and ignite? The thermostats are connected to the pipes at either side of the unit.The only number that looks similar to that format is 41 094 03 would that be the number you need?
Expert:  Andrew Smith replied 1 year ago.


Does the fan run?

Does the ignitor spark?

Customer: replied 1 year ago.
It certainly sounds like the fan is running but that's it. No spark from the ignition.
Expert:  Andrew Smith replied 1 year ago.

Ok, it does not know it is lit then, you should check all the connections on the air pressure switch.

If they all look ok then replace it.

Customer: replied 1 year ago.
Thanks for your help. I'm going offshore tomorrow so I've bit the bullet and called in British Gas to fix.
Expert:  Andrew Smith replied 1 year ago.

No problem, it would be interesting to know what they find.

Related UK Plumbing Questions