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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
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Sabre 25he boiler, no ignition sequence, dif switch is open,

Customer Question

Sabre 25he boiler, no ignition sequence, dif switch is open, pump runs, water switch ok, fan runs, new dif switch used, new venturi pipes and venturi replaced, cleaned heat collector, checked flue for obstruction, open main cover to combustion chamber ignition works, close chamber cover, ignition stays in for a minute then goes out, it seems to me pointing to the fan not running correct speed, checked ladder logic within Manuel,
Submitted: 1 year ago.
Category: UK Plumbing
Expert:  Andrew Smith replied 1 year ago.

Sounds like a fan/Venturi problem.

What happens if you disconnect one of the APS tubes at a time and try?

Customer: replied 1 year ago.
If you remove tube where air is sucked in, and gently suck switch closes and starts ignition, put tube back ignition goes out
Expert:  Andrew Smith replied 1 year ago.

Ok, is the tube not sucking?

Make sure the other is blowing - try soapy water over the end and see if it blows a bubble?

Customer: replied 1 year ago.
Other tube is blowing, not at boiler yet, tried earlier, will try soap solution, however if this is not blowing, can the fan be the issue, as I've checked all dc voltages as Manuel states and comes to an end with no conclusion, other than my theory of the fan not running at correct rpm
Expert:  Andrew Smith replied 1 year ago.

Yes, the fan may be turning, but impeller may be broken internally and not producing enough power to trigger the APS

Customer: replied 1 year ago.
Ok I am going down the route of purchasing a new fan, and will take it from there I think, I thank you for your assistance, and will try this
Expert:  Andrew Smith replied 1 year ago.

No problem.

Let me know how you get on

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