Megaflo unvented cylinder no hot water???

[Andagain1001]

Hi all
I have a Megaflo indirect unvented cylinder.

HW has stopped getting hot-still get water from hot taps but it’s cold.

Boiler (Ideal Classic HE) and CH work fine.

Honeywell programmer-when HW is turned on the programmer used to make a clear click, now I can hardly hear it.

2 port valve does nothing when HW is switched on, boiler doesn’t fire.

Have pushed the thermal cut out reset on the Megaflo so am guessing that’s probably not the problem, also Megaflo does heat up water using the immersion back up.

So, I’m thinking it’s either the 2 port valve or the programmer which is the problem, just checking to see if anyone thinks I may have missed something, or if I can tell which of the programmer or the valve the problem is?

Many thanks

 

[muggles]

If you have a Honeywell ST9400C programmer it's most likely that that's gone wrong, as there was a bad batch of them that failed prematurely. Only way to be certain is to open up the wiring centre and test to see if the brown wire to the zone valve goes live when you turn the programmer on. If it does, the ZV is at fault, if it doesn't the programmer is at fault

 

[Agile]

Repairs to the HW control circuit probably need to be done by someone who holds a G3 unvented certificate.

Tony