Central heating OFF, HW OFF, but boiler OK?

[Lobster]

Woke up to no hot water or central heating this morning, and SWMBO is not a happy bunny. Would be grateful for any thoughts as I'm stumped...

System is a Worcester-Bosch 30CDi system boiler, with unvented HW cylinder. It's at normal pressure, is displaying no error codes, and the pilot light's on and it's 'warm'. If I set either the CH or HW (external) controller to override, nothing happens.

I've tried sliding the little manual lever on the control valve, to no effect, but in fact presumably that's not a likely source of the problem as both HW and CH are out?

The wireless roomstat has been set to manual override for some time (that's another story) but again, I wouldn't suspect that anyway as the HW is off too.

My thought was the system pump must be out; however this is built in to the boiler so surely to God it would display an error code if that was the problem?

FWIW the manual is at (or )

Thanks for any help

[fred]

In article , Lobster writes

Get the meter out, check it is getting power then check to see if it is getting demand when the thermostat(s) are calling for heat.

This will split the problem in half, either in the boiler or in the external controls.

Moving the zone valve actuator manually will not activate the microswitch in the valve so will not cause the boiler to fire but if you remove the cover[1] from the valve, open it manually and then activate the microswitch too then you should see a demand at the boiler.

Follow the trail in the failing direction until you find what is not operating.

[1] bare live parts will be exposed

[Jonathan]

We had this a few months ago. It was a faulty card that controlled the fan so it never properly ignited. Just still in the five year warranty period so cost nothing this time - it's the second time it has happened.

Jonathan.

[John Rumm]

I would have thought that was too new to have a pilot light?

The programmer would be my first suspect - since it is a single point of failure that can inhibit both demands from the room and cylinder stats (assuming the cylinder has a conventional stat?)

If its your normal honeywell style two channel programmer, it probably has a standard(ish) mounting plate, so that you can loosen the retaining screws under the programmer, and take it off its wall plate. That leave the connections exposed at the plate where you can get to the (live mains!) contacts. Ensure the room stat is calling for heat, and short the live to pin 4 (CH On), and the boiler should fire (allow a few secs for the valve to trundle round).

That won't cause a demand to go to the boiler anyway - even if the stat is calling for heat since it does not usually close the microswitch on the valve.

You would expect so - if it ran for long with no circulation you would expect it to lockout.

[mogga]

Does it have a battery in it?

[Roger Mills]

I'm wondering whether there's something silly going on. It sounds as if it's an S-Plan system with two 2-port zone valves. If so, each of the valves will be driven by the programmer and the respective thermostat - room or cylinder. The auxiliary switches on the valves will switch on the boiler and pump when either or both valves are open.

These auxiliary switches have to be supplied with a permanent live - which usually comes from the same source as the rest of the system.

*However* if the system had been wired in such a way that the permanent live came from a *different* source, and if that source were to fail (blown fuse or somesuch), it just might explain the symptoms. The programmer and stats could be calling for heat - with all the right lights on - but nothing would physically happen. Is this a possibility?

[Lobster]

Lobster grunted in news:XnsA26D881E8E3C5davidlobsterpot601@81.171.92.236:

Thanks for the feedback on this.

Ran out of time (and SWMBO patience!) with my investigations at the weekend and had to call the plumber on the Monday morning. Turned out to be a failed control valve, no more no less, but I still don't get how this took out both HW and CH

[Lobster]

Lobster grunted in news:XnsA26D881E8E3C5davidlobsterpot601@81.171.92.236:

Thanks for the feedback on this.

Ran out of time (and SWMBO patience!) with my investigations at the weekend and had to call the plumber on the Monday morning. Turned out to be a failed control valve, no more no less, but I still don't get how this took out both HW and CH

[The Natural Philosopher]

may be the only control valve there is.