I have a Halstead Finest Gold Boiler which intermittantly goes into safety lockout. (Red LED permantly on) The fan remains on until the power to the boiler is removed. I have tested the APS which is OK. I have cleaned the products of combustion from the individual fan blades, and cleaned the venturi. All clear. Driving me quietly mad. Wife reckons I am having some kind of affair with the thing. Cleaned crimps, soldered directly to the gas valve as those crimps looked tarnished. Everything looks OK. I have looked at the PCB and all seems OK, no dry joints etc. It still seems that the APS is dropping out, and shutting the thing down. One thing I have noted is that this fault happens in the evening, and the voltage here drops to about 218 volts as we are on overhead cables. The question is whether the fan is voltage dependant and slows down enough to trip the APS. I don't know quite how the fan motor is wound. Is it voltage dependant? The whole thing seems on the edge. There is no air in the system, and it can work for days without a problem. The fan remaining on must be a clue. I wish I could get ahold of the PCB circuit diagram as that would tell me what the boiler thinks is happening. Any help would be appreciated.
Halstead Finest Gold Lock Out
- Thread starter nickd
- Start date
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Have you tried following the the fault finding section of the manual?
Well seeing as the most minute layer of dust or tiny strand of spider web in the venturii will drop out the air pressure switch I would imagine a voltage drop of 10% or so could quite easily achieve the same with an amount of wear on the components.
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Yes I have, but it doesn't have the failure mode listed. The last box says "When the fan stops is the Red LED illuminated"
The fan in my boiler keeps runnung
Be aware that we dont advise DIYers to even open the combustion chamber as that should be done by a competent gas registered engineer.
What you can do though is to identify the APS connections where they connect on the the PCB and monitor its operation ( or not ) by measuring the voltage across the NO contacts. Be aware it probably expects continuity on the NC contacts before the fan starts.
Also disconnecting one fan supply will also prevent the APS from operation and enable you to see the measured effect on the APS connections at the PCB.
The APS contacts should be less than one ohm when made.
Tony
What you can do though is to identify the APS connections where they connect on the the PCB and monitor its operation ( or not ) by measuring the voltage across the NO contacts. Be aware it probably expects continuity on the NC contacts before the fan starts.
Also disconnecting one fan supply will also prevent the APS from operation and enable you to see the measured effect on the APS connections at the PCB.
The APS contacts should be less than one ohm when made.
Tony
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