Baxi 105e, no CH, uuurrgh...

[rojaca]

internal timeclock-grasslin type? if so check between N and both sides of switch. should have 240 L-N on clock switch (not between tor live and neutral on clock)
sorry if you've saidabove what your set up is-too late and too tired to read

 

[gavinda]

internal timeclock-grasslin type? if so check between N and both sides of switch. should have 240 L-N on clock switch (not between tor live and neutral on clock)
sorry if you've saidabove what your set up is-too late and too tired to read

this is what i meant....just put better

 

[dar2008]

Ok, really really strange... CH now works, but don't know why...

After sending the kids to bed with hot water bottles last night, I turned the boiler off overnight.

This morning turned it back on and it was exactly the same... HW, but no CH, even though the controls were demanding it The HW light was permanently 'ON' on the front of the boiler, but the CH light didn't light up. The boiler seemed to be running and firing up every few minutes, with the temperature lights gradually increasing before it cut out. (pre-heat is turned right down).

I then turned the hot tap on in the kitchen where the water came out hotter than 'normal'. Oh well I thought, time to call a plumber. Went back to the boiler and low and behold, HW light was now out, CH light was ON, boiler firing and radiators getting hot.

Fantastic, but something has caused this to happen and I guess will need replacing / cleaning. Any ideas what could have stuck here so I can prevent it reoccuring?

Thanks in advance.

 

[dar2008]

Has no-one any ideas what could have caused the CH to stop working, but now it is working? Something somewhere must have stuck.

 

[Baxmax]

Something might be faulty

 

[nogoodatfaultfinding]

Something might be faulty

On the instant i would guess its the divertor pin BEHIND the Small Diaphram Assy sticking between HW an CH, changed loads of these and at a guess its getting enough from the mains cold to push forward and work the HW and then not moving back to CH.
And that would explain the demand light and no CH

Like i said its a guess

The instant temp rise and cut out is also a first sign of this, I personally however have only seen it on HW side.

 

[onlyfitidealboilers]

ntc most likely ok at low settings, but as it gets hot it goes out of calibration, how do you know you had 240v on the switch live did you test it? if so what with?

 

[rojaca]

if your dhw light is on constant then blr thinks there is dhw demand. it will therefore not allow the heating to come on as dhw takes priority.
as ngff says either siezed diverter/pressure differential spindle or a duff dhw microswitch.