Central Heating system partially on problems

[richmarks]

Hi,

I have the following set-up.
Rayburn 380G , with Lifestyle LP241 controller. Dual zone.

When the timers are off, the water pump is on constantly, the water heater part of the rayburn is on for short durations, and one radiator is warm.

I have the following observations:
1. When I take the power off - it all shutsdown
2. When I set turn the thermostat on the rayburn down or to zero, the rayburn goes off, but the water pump stays on.
3. After some on/off the system settled down and the pump stopped (having been running all night with the cw & hw off on the timer)
4. The ch valve & hw valve seem to be operating ok
5. The pipes upstream & downstream of the ch valve were hot. For the hw valve - cold.

My questions/theories :
1. What starts the pump/heating system ? Can it be that the ch valve is faulty and not closed properly. Does this somehow intiate the pump & boiler to fire ?
2. Why would only one radiator be warm - could this be a heatsink for the rayburn, or could it be that with only a small ch flow (passing faulty valve) the heat is only getting to the 1st radiatir in the system. all the pipes are behind the walls so I can't see the radiator line-ups.

Any thoughts would be appreciated before I call an engineer (i haven't been successful with them in the past, so wish to mug-up before hand so I don't get fobbed off)

Any help greatly appreciated

Cheers

Rich

 

[Burnerman]

On a Rayburn 499 which I have been (and still am) battling with, the circulating pump is controlled by an overrun stat, that keeps the pump on once the water temperature in the boiler reaches 60 deg - useful if it has just reached a timed off period and the water is still hot....maybe this could be an issue with yours?
John

 

[richmarks]

Thanks for the reply.

How can this expalin the boiler actually firing ? I assumed the stat would just keep the pump running with no heating. Also the valves indicate closed (cw & hw), even with the pump running

I actually see the boiler firing on & off all night - only for short periods , but the pipes are redhot, even though only on radiatior is hot/warm.

Thanks

Richard

 

[jackthom]

If both zone valves are really closed the water will be pumping around the bypass which will only need short bursts of heat to keep things very hot.

The boiler must be getting a continuous signal to fire up from somewhere in the control system, most likely from one of the motorised valves which may have a stuck microswitch.