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Plumberpro, Home Appliance Technician
Category: Appliance
Satisfied Customers: 634
Experience:  Heating and hot water heating appliances experienced
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Hi My Baxi Solo 24HE has intermittent fault on the lock out

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My Baxi Solo 24HE has intermittent fault on the lock out circuit. Is the condenser sense and the flame detect the only two elements on this circuit? Boiler works fine when running but often the lock circuit kicks in. Any suggestions?
Thank you.
Hi , the boiler also has a safety stat which will detect overheating . there is also a flow switch which will lock the boiler out.
If your pump is on the way out, this would affect the flow switch or safety ( overheat) stat.
Also if the system is sludged this can cause issues with those two as well.
There is also a fan overheat stat, which detects if the fan is running ( by temperature) if the fan is on the way out and off its bearings a little this could cause that stat to kick in.
Also there is a sensor on the condensate trap, if this gets blocked and the water reaches too high up it will lock out.
Quite a few things , which is why an intermittent fault can be a right pain.
Check the condensate trap isn't blocked.listen for noise from pump/ fan , check the pipe out from the boiler is it red hot ?
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Customer: replied 2 years ago.


Thank you for initial reply which helps somewhat. Given that there are other sensors at play do you have any advice on how to isolate them so that I can pursue the root of the problem. I accept these are safety features but what would an engineer do in pursuit of the problem?

would turning down the heat control improve the situation. As we arte now in Summer (no heating on) is the boiler too efficient for just the hot water loop?

I am happy to rate your answer as requested.

Thank you for your support.


Hi , definitely worth trying turning down ,if it runs OK then you know its a temperature issue, due to sludge or pump.
If you have a multimeter the fan can be tested on ohms .
The problem of intermittent faults is that are hard to pinpoint without going through every component and testing them individually with a multimeter on ohms .
This is why British gas don't even attempt it but porefer to wait till the component completely fails.
If you do have a multi Meyer let me know
Customer: replied 2 years ago.


Didn't know my first reply went through, apologies for repeating it. The system tried to ask for more money but then I realised I hadn't submitted my rating.


Yes I do have a multi-meter.

You could check the pump should be within 170 to 270 ohms.
Fan should be between 40 to 80 ohms. Less than 20 and more than 80 replace.