Roger Mills wrote:
On 07/01/2013 11:36, Chris wrote:
Hi,

I have a Baxi 80 HE plus which firstly works fine for the hot water
system. However for the central heating several times a week, the
Central
heating does not come on as per timer controls. Although the lights
on the timer control light up as expected when the timer is set to
swich the heating on, the boiler does not fire.

However with several goes at switching the timer control on and off
e.g. clicking advance or boost and pressing the reset button on the
boiler , the Central heating will eventually fire up ( 2 green
lights) and stay on until the timer control switches it off later in the
evening.

There are no red fault lights showing on the boiler when it doesn't
fire- in fact when it doesn't fire up there are no green lights
either showing on the boiler.

The pressurised system is just over 1 bar.

Any ideas if this is more likely to be a timing control (Drayton
Tempus 7) which I could easily get replaced or a boiler problem (
lots of money)! Thanks for any help

Chris



Are there any motorised valves in the system? If so, you could have a
problem with one of those. Assuming that your boiler isn't a combi
(I'm not familiar with the model, so I don't know) you may have a
motorised valve for each heating and hot water zone. If it's an
S-Plan system, the timer/room stat will control the valve and the
valve will switch the boiler on when it's open. So if the valve
doesn't open, or if it does open but its auxiliary switches don't
work, you'll get no heating.
Could this be your problem?

I'll raise your 2 port valve with a faulty mid position valve:-)

--
Adam