Heating wont shut off

[Rebdam]

Hi, I have had a plumber and a spark out to look at this and they are both scratching their heads and blaming the other - so any suggestios will be gratefully received! I have an oil fired central heating system with two zones. The first zone CH, when turned on at the Horstmann Channel Plus programmer will fire the boiler and heat all the radiators downstairs and the hot water. When I press HW this heats the hot water and turns all the radiators on upstairs. For a few weeks now when the programmer clicks off and the lights go out but the heating remains on upstairs. Even if I turn the dial on the thermostat down I wont hear a click to let me know the heating is going off - it just doesn't register that I have set the temperature and keeps heating the radiators. The thermostat clicks OK when the programmer lights are on but not when the heating is firing with no light. We tried changing the thermostat - but the issue still arises. Changed the Actuator Danfoss HPA2 and still no joy. This problem only seems to occur upstairs and the downstairs section comes on and off correctly and shuts the boiler down (as long as the upstairs heating isn't on at the same time) Now the spark thinks that this may be the timer as the lights are out but the boiler is still firing? Anyone have any input? I just feel we're throwing good money after bad as it seems like guess work

 

[gassafeengineer]

employ someone decent is my answer a good engineer or electrician would be able to tell wether clock is giving out feed when off wether stat is making and breaking wether motorised valves are open and wether end switches are making and breaking. just disconnect clock when fault occurs this will tell you if it is the clock at fault

 

[ChrisR]

SOunds a bit muddled.
Check to see if motorised valves and their switches are opening and closing properly.

Then the one you feared - check all the wiring.

 

[Rebdam]

Thanks for the replies - when the clock is disconnected the boiler shuts down.

 

[gassafeengineer]

relay in clock is not switching off. New clock it is

 

[twgas]

when the clock is disconnected the boiler shuts down

relay in clock is not switching off. New clock it is

Surely that depends which wires were disconnected.

 

[gassafeengineer]

If the clock has been removed there is no need to disconnect wires there can be no signal

 

[Rebdam]

I just removed the clock face and it shut down the boiler down. Surely it has to be an electrical fault if the clock is set to off and the heating is still running? Does anyone know if a valve left open by the actuator can cause the heating to continue to run even if the clock switches to off?

 

[stardanny]

sometime a sticking / jammed valve can keep the boiler going even the Actuator is off.

I'm not sure but has the valve been changed or just the motor head?
Remove the actuator head and check that the valve spindle on the body is moving free.

If the valve moving free and okay then it may be a faulty programmer.

Dan.

 

[Rebdam]

Just the actuator was replaced. Spindle on the valve moved freely when I checked it and I can hear it opening when I turn the heating on. It just seems weird only one zone of the house keeps heating and it is completely ignoring the thermostat so even if its set to 10 degrees the radiators are still on and piping hot

 

[WDIK]

its wired uncorrectly with the limit switch calling for heat as does the clock.