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Andrew Smith
Andrew Smith, Engineer
Category: UK Plumbing
Satisfied Customers: 3589
Experience:  Domestic Gas, Commercial Gas, LPG, Unvented Hot Water, Part P Electrical, Commercial Catering
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I have a greenstar 25Si/30Si boiler. We have been away for

Customer Question

I have a greenstar 25Si/30Si boiler. We have been away for two days and come back to find no hot water or heating. The main blue light is flashing rapidly and the pressure is on zero. We have tried resetting it and then putting the boiler on. It sounds like it fires up but then the main blue light starts flashing again.
Submitted: 4 years ago.
Category: UK Plumbing
Expert:  Andrew Smith replied 4 years ago.
Hi my name is XXXXX XXXXX lets see if we can get you sorted in the shortest possible time. do you have a silver flexible pipe under the boiler or a key attached to the bottom panel that slides off?
Customer: replied 4 years ago.
there is a silver flexible pipe
Expert:  Andrew Smith replied 4 years ago.
Turn the tap on at one end and the slowly at the other end until it starts whistling through. Let the pressure get to about 1.5 bar and then turn both valves off. Done.
Customer: replied 4 years ago.
I think there is a word missing before slowly! So not sure what to do
Expert:  Andrew Smith replied 4 years ago.
"then" as in just crack it open.
Customer: replied 4 years ago.
Have done it. The pressure is now 2.3. Is that ok? Can we try the boiler or is it too high?
Expert:  Andrew Smith replied 4 years ago.
You can turn the boiler on now. It is a bit high and you want to vent one of the radiators into a tub to drop it to about 1.5 bar
Customer: replied 4 years ago.
Have done that. Boiler makes a noise as if it is coming on but then the blue light starts flashing again and no heat coming
Customer: replied 4 years ago.
Relist: Incomplete answer.
Expert:  Andrew Smith replied 4 years ago.
Is it a fast or slow flash?
The boiler model you have listed is from the book, do you have the GC number from the boiler?
Customer: replied 4 years ago.
It is a fast flash. We don't know what a GC number is but can't see a number on the boiler.
Expert:  Andrew Smith replied 4 years ago.
It is usually on a sticker underneath or on the back of the control box
Customer: replied 4 years ago.
Have found it. GC 4731185NG
Expert:  Andrew Smith replied 4 years ago.
That's great - it narrows it down. Is there just the one light flashing?
Customer: replied 4 years ago.
Yes just the main blue one. There are no other lights on at all. When you reset it, it stops flashing but as soon as you put the boiler on it starts.
Expert:  Andrew Smith replied 4 years ago.
You will need an engineer to check this out. Fast flashing blue light means the following;
Temperature sensor fault
Wiring harness fault
Fan fault.
Can you take the front cover off and see if the fan is running?
Customer: replied 4 years ago.
No cant seem to move front!
Expert:  Andrew Smith replied 4 years ago.
You should call an engineer and inform him of the progress you have made.
Customer: replied 4 years ago.
Relist: Other.
the answer did not resolve the probem despite sitting in front of the computer for the best part of two hours
Expert:  Andrew Smith replied 4 years ago.
Do you expect to fix it yourself when it sounds like needing a part? If you send me your Gas Safe registration details I will give you further details?

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