CH not coming on, but HW is fine All aspects of plumbing questions and answers, help, tips and information

[diyjunky]

Hi all,

I've just come back from holiday and now the weather is turning decided to stick my CH on for a while. Unfortunately, even though my HW is fine, the CH refuses to come on. I haven't used the heating since around early May but it was working fine at the time.

I have a wireless thermostat (British Gas T4RF) connected to a WR1 receiver which is in turn connected to a Honeywell ST9400C programmer:

[IMG]http://i38.tinypic.com/beiil4.jpg[/IMG]


Thermostat appears to be working fine, and the wireless receiver successfully receives signal and in turn the "ON" LED light comes on to call for heat.

I've got the programmer set to constant for both CH and HW right now to try and eliminate the unit as the issue.

It's here that it goes a bit pear shaped, with the WR1 showing a call for heat (ON) the boiler fails to ignite, but I'm almost certain that the problem lies with the valve. I have two two-way Honeywell valves, left one for HW and right one for CH:

[IMG]http://i34.tinypic.com/104ql36.jpg[/IMG]

The only difference between the two is that the lever on the left is slack when the HW is on, the lever on the right valve (circled in red) is constantly stiff.

I have manually pushed the lever over to the left (opening the valve) and held it - at which point the rads started to heat up.

I'm no brain surgeon but I presume this might indicate that the electronic valve is broken perhaps? is there any way I can test this to make sure thats the case or are my above steps sufficent to diagnose?

My plumber can't come out until Monday so I just thought I'd check if there's anything I can do beforehand.

Thanks.

[diyjunky]

Not sure why the images aren't working :? guess you'll need to cut and paste the image URLs if you want to see them.

[plumbbob]

Switch everything off at the main switch and compare the two levers on the valves. Obviously they should both now feel identical. Are they?

If the feel of the gears is the same for each, there is little more you can do to identify the problem without electrical test equipment. As I see it, everything you have explained and done is correct and the heating should be on.

If you need the heating on whilst waiting for the repair, the lever can be hooked in a slot at the end of it's travel keeping the heat in the "on" position.