No hot water but heating through the radiators working?

[Big B]

looking for advice please gents and ladies
we’ve had a failed boiler recently replaced and have gone for a system boiler but kept old copper tank for the hot water but converted the heating from open vent to pressure as the new Worcester Bosch 4000 Boiler we have been advised can only run on pressure.

problem that has arisen we have had hot water supply till this evening, the pressure on the heating side is in the green 1.4 bar and the heating works just fine.
we have kept the old program timer which is a British Gas one, (similar to the Drayton controller), hot water control timer is on but the boiler is not firing up, the boiler is only a few days old so don’t think there’s a problem there but could I be wrong and there be a fault there or could an air lock be causing this? Or
could we have a thermostat issue?

any other causes I may have left out as I’m stuck with the problem and can’t find the saloution.
we do have immersion as fail safe so using that in the meantime.

 

[JohnD]

the boiler is only a few days old

Was it installed by a competent person?

Have you paid them?

 

[oldbutnotdead]

Very unlikely to be a boiler fault given that it's a system boiler and the heating is working.

Do you have motorised valve(s) anywhere in the system?

Have you checked that the cylinder thermostat is set to your required temperature (50 plus usually).

 

[Big B]

Hi

Very unlikely to be a boiler fault given that it's a system boiler and the heating is working.

Do you have motorised valve(s) anywhere in the system?

Have you checked that the cylinder thermostat is set to your required temperature (50 plus usually).

Hi yes
motorised valves on the hot water but haven’t checked thsee? When and what should they be doing When I turn on the hot water on controller?
thermostat set to 70 and still not activating boiler fire up

 

[Big B]

Was it installed by a competent person?

Have you paid them

hi John
yes we had an accredited heating engineer fit it for us but and he’s done a fab keeping it tidy etc, he knew what he was doing but like most of The large heating companies they close at 5pm

yes paid unfortunatel

 

[Johntheo5]

Can you turn the cylinder stat down until you hear a click then keep turning it back up until you hear another click, if you do, watch or get someone to watch the motorized valve opening shutting, allow say 20 secs after each click.
When you say motorized valves you mean that you have a separate valve for the HW, ie just two pipes on the motorixed valve and not three?
If a two pipe (port) valve then with the cylinder stat turned right down you should feel a fairly stiff resistance when you are pulling the mot.valve manual lever across, if the lever feels floppy with little resistance then it's failed.

 

[Big B]

Can you turn the cylinder stat down until you hear a click then keep turning it back up until you hear another click, if you do, watch or get someone to watch the motorized valve opening shutting, allow say 20 secs after each click.
When you say motorized valves you mean that you have a separate valve for the HW, ie just two pipes on the motorixed valve and not three?
If a two pipe (port) valve then with the cylinder stat turned right down you should feel a fairly stiff resistance when you are pulling the mot.valve manual lever across, if the lever feels floppy with little resistance then it's failed.

Hi John
report back on all…Sorry I’ve been fitting a kitchen utility all day today.

so I've gone back home and changed the tank stat and that’s working as it should. However once done I then moved to the MV test you suggested on both the CH and HW valves and found that the HW valve faulty, removed the valve and found a loose screw inside replaced it and voila the valve miraculously started working again. Brilliant suggestion by yourself I would never have considered Those as they’re fairly new.
(Btw repairs carried out with circuit breaker in the off position)
now it’s doing what it needs to but just for safety I’ll replace the HW valve Just in case the gearing is damaged.
I would like to thank you for taking your time to reply to me it’s been very much appreciated you have been a brilliant support to me. especially when the decent plumbers heating engineers aren’t available for weeks.
Oh and the wife says thank you too we nailed it.
regards Bruce