baxi boilers?

[jug]

that manual confirms that auto is the 2 stage mode, allday is the one stage, on is constant and off is off. i would carefully follow the programming procedure described in the manual to ensure you have set your program correctly for the times you want it to come on. its a complicated programming procedure.

if your boiler thermostat is set on low in winter then the boiler may never stop boiling, but only during the times it should be on as dictated by the programer, so your problem must be with the programmer, either how you programmed it or it is faulty.

 

[poggy]

Does it come on during the night as well as the day. If it doesn't come on at night it is the programmer at fault. It is pretty easy to test, just look at the 240V supply from the clock to the boiler. If 240V is present when the timer is set to off, it is either a timer set up or faulty timer. The room thermostat and tank thermostat are irrelevant as the timer provides power to run them and when it is off the whole system is off.

The three way valve is used to divert water to either radiators, hot water or both hot water/radiators depending on the signal from the timer. There are sensors on it to make sure the valve is in the correct postion.

 

[arc]

it comes on at night as well as during the day. also, the upstairs rads are getting hot - using water from the hot water cylinder it seems cos the CH is still set to OFF.

i've had a look at the wiring:




So looking at this..

It's wired as Y plan system, L4 and L5 are cut but L6 is not meaning the boiler does not require pump overrun.

There is nothing connected to the HTG valve block, so the frost stat is not installed.

looking at the plumbing side of things, it does look at bit OTT.. i tried to draw what was going on, but gave up and just pointed the video camera round a bit

http://tackycheese.net/images/misc/ch_mpg.avi (6.6mb)