No hot water

[queuemaker]

Baxi Bermuda Back Boiler.
Programmer moved after wall demolished but now no hot water (radiators get hot). Wiring and programmer checked and OK, but boiler does not fire up when HW selected. Any ideas ?

 

[weargas]

the boiler doesn't fire up at all or fires up for a few minutes and switches off?

 

[queuemaker]

It doesn't do a thing !

 

[weargas]

the fact that this has only happened since the programmer was moved would send me straight to the wires that have been altered but if you say they've been checked then any advice given is assuming they've been checked properly and it is wired up correctly. Have you got a gravity fed dhw system or is it fully pumped?

 

[queuemaker]

I believe that it is a gravity fed system, but if so how does the hot water reach the tank upstairs in the airing cupboard without a pump as convection alone will not cause sufficient heat to heat an entire tank of hot water. I was wondering if there was a seperate fuse in the back boiler controlling the HW system that might have blown ?.
Also, I have replaced the tank thermostat which I though was my initial problem.

 

[ollski]

It is a wiring problem....there does not seem to be a call for heat from your cylinder stat. Does it make any difference if you turn the stat right down?.

Gravity is purely operated by circulation and works great unless somebody puts in a long horizontal run or even a slight drop in the rising flow pipework...that will stop it dead, it would however still fire up the boiler until the boiler stat cut in

 

[queuemaker]

still no luck with the HW. I have tried everything and have checked all the wiring but still no joy. Is there any way to bypass the tank thermostat so that the HW is always on when the timer is selected ? I could then control the HW by the timing selection, since I only need it first thing and late at night ?