S plan no hot water fault diagnosis.

[cdbe]

Is there a guide anywhere? Cylinder is a megaflo.

Heating fine, everything was switched off for a week while away but made hot water fine when switched back on on Friday evening, the RCD tripped on the circuit the boiler is on yesterday but reset straight away (I suspected washing machine at the time as it's on its way out) so it it could be related but can't remember if water was timed on at the time, I don't know whether we have had hot water since then as cylinder is quite big so didn't run out till this morning.

Programmer has power so should I start at the wiring centre, cylinder stat or straight to messing with lever on valve?

Thanks

 

[oldbuffer]

1. The cylinder is unvented, so the motorised valve on the coil is part of the safety system. Should only be touched by someone with current G3 qualification.
2. These normally have one or two immersion heaters fitted. The top one should give you a limited amount of hot water if on.
3. With respect to the boiler hot water side, if you have a multi-meter, know how to use it and are comfortable working with mains voltage electricity you could test for 230V at appropriate points.
4. If it turns out to be the motorised valve not opening, or not firing the boiler, get a G3 registered engineer to replace it.

 

[ianmcd]

Check if the overheat thermostat on your HW cylinder has tripped, and press it in to reset if needed, this closes the motorised valve when it trips

 

[cdbe]

Thanks, it was the motor on the valve, more a case of spotting the scorch marks backed up by a bit of metering than following a sequence. Fortunately I had a spare Honeywell valve and the motors were a straight swap.