Baxi Bermuda 552 Back Boiler no Heating

[Mark Culverhouse]

Hi all
After a little help, got a client who's boiler is not calling for heat, His programmer packed up and I replaced it like for like (Drayton Lifestyle), checked the 3 port valve and that is working as it should, But this is the issue.

Call for hot water only - works as it should
Call for hot water and central heating - works as it should
Call for central heating only - nothing happens

the heating is controlled by a thermostat on the front fireplace of the back boiler (yes very old system) has no standard room thermostat and the temperature of the rooms is controlled by TRV's on the radiators.

Too me this is pointing to the thermostat on the fireplace being faulty am I correct

Thanks in advance

 

[cross thread]

Probably not wired to do heating only

 

[Mark Culverhouse]

That's what I thought but it's wired as before and client said he could always select heating only.

back plate wired as below

N - Neutral
L - Live
1 - HW Off 9 ( wired )
2 - CH Off ( not wired )
3 - HW On ( wired )
4 - CH On ( wired )

 

[cross thread]

Not altered the settings on the back of the clock

 

[Mark Culverhouse]

Yep set to the same as previous programmer P for pumped allowing both HW and CH to be set Separately

 

[gas112]

for heating to come on by its self power need to come from terminal 1 Hw off to motorised valve which then makes it move to heating only position . I would say motorised valve head is faulty