no CH ?

[Vass]

Old Wicks boiler with emersion tank Call for Hot water and Boiler fires up ok Call for heat, nothing from the boiler, 3 way switch doesnt move, nothing at all happens

Over ridden timer asking for 24hour CH, still nothing.

any idea folks where I should start looking? TIA

[Bob Minchin]

I presume when you write "3 way switch" you mean "3 way motorised valve"? if so, then check this is working both mechanically and electrically. Check the wiring to the microswitches inside. These will be part of the logic used to fire the boiler.

[Tim S]

Vass coughed up some electrons that declared:

OK, so boiler is working OK, and electrical supply to the system as a whole is OK. Sounds like a localised electrical fault, on the CH side.

You have a 3 way water/zone valve by the way you are describing it. If the lever doesn't move of its own volition, my money is on either:

The hall (or wherever) thermostat has died, so it never calls for heat, which, in conjunction with the programmer would instruct the zone valve to move, supplying water to the radiatiors.

Or the motor coil in the zone valve has blown.

Or just maybe, the zone valve is seized (less likely as it's moving all the time).

Ouside chance - the programmer has a fault and isn't calling for CH even though it should.

Two things to try:

If the programmer and room stat are set to call for heat, can you move the zone valve lever by hand (it's a manual override feature). If so, does the boiler then fire?

Test the wiring at the hall/room stat and see if you get a live supply in and a live return when the programmer and stat are calling for heat (usual caution about high voltage etc etc). This will verify the programmer and the hall stat.

Some systems (many?) have a microswitch in the zone valve that requires the valve to be proven to have operated before engaging the boiler, which is why I suggested trying to manually operate the valve.

Basically, on that type of system, the programmer CH demand live supplies the hall stat which supplies the zone valve motor to supply the rads with water, or some variation on this. The microswitch in the valve then supplies the demand for heat signal to the boiler.

Other variations are possible, so if this makes no sense, don't panic.

Cheers

Tim

[Vass]

Thanks for info Tim

The 3 way valve moves manually to the end and an audible switch can be heard coming from it, but no boiler coming to life.

If I hold this accross on the valve and alter the timer to call for hot water there is a massive noise coming from the receiver of the Sunvic RF thermostat, once I release the valve it moves back to its correct place and the buzzing from the receiver stops.

guess its the wireless room stat receiver thats buggered?

[Vass]

Oh and there is a Test button and an Install button on tis receiver thingy, pressing either does nothing and the red led's next to each button do not light up

[Tim S]

Vass coughed up some electrons that declared:

Sounds like the thermostat is knackerd. Assuming you feel happy to do so, can you bridge the thermostat receiver supply live and demand (output) lives togther and see if the system then works.

That will at least give you some heating based on programmer alone.

Cheers

Tim

[Vass]

Thanks Tim will go and give it a go

[Vass]

Put the original manual thermostat on and everythign is working fine Off to Screwfix in the morning for a new wireless controller Many thanks for the tips and helping to sort the problem so quickly Cheers

[Tim S]

Vass coughed up some electrons that declared:

Ok - that's teh microswitch, so yoy know that the valve affects the control circuit as well as being controlled by it. Cheers

Tim

[Tim S]

Vass coughed up some electrons that declared:

Splendid.

I think all CH components should have little neons in them so you know what's working and what isn't...