Boiler not turning off

Kowerski

Looking for some advice. I have an oil boiler. Standard boiler which was serviced last year. Was working perfect and now all of a sudden it will not turn off.

It has two motorized valves, one for heating and one for water. I thought maybe this was issue and one wasn't closing off but check this morning and they are working. If I turn the thermostat down as well on either they close.

What else could be calling the boiler to stop it turning off?

Wearb

They could be closing the water valve part but leaving a faulty contact in play. You could check with a voltage measuring device.

jimf

as wearb said above

if both valves are close together and the same type you could swap the actuators and see does the problem move as well

DGOBS

jimf, but if there is a faulty (stuck NC) contact in the mv, it won't make a difference

jimf

DGOBS wrote: »

jimf, but if there is a faulty (stuck NC) contact in the mv, it won't make a difference

I know what your saying tony

but if the heating is constantly on without a heat call swapping the actuator from the hot water valve should show if the actuator is the issue

I know it need to be wired etc

John.G

What about ensuring neither zone calling for heat and actuators closed as per post #1,
follow the wiring back from any one of the actuators to its junction box and remove the orange wire and see if boiler cuts out or doesn't restart after waiting for maybe 30 minutes or so to allow the boiler stat to make. OR if a M.meter to hand test for (no) voltage between orange wire terminal and earth, if only a phase tester handy place it on the orange terminal, it won't light if contacts are correctly open.

I have only replaced two/three actuators for relations but in each case the zone valve was passing slightly and the manual lever was "floppy" with little or no resistance to movement.

Kowerski

John.G wrote: »

What about ensuring neither zone calling for heat and actuators closed as per post #1,
follow the wiring back from any one of the actuators to its junction box and remove the orange wire and see if boiler cuts out or doesn't restart after waiting for maybe 30 minutes or so to allow the boiler stat to make. OR if a M.meter to hand test for (no) voltage between orange wire terminal and earth, if only a phase tester handy place it on the orange terminal, it won't light if contacts are correctly open.

I have only replaced two/three actuators for relations but in each case the zone valve was passing slightly and the manual lever was "floppy" with little or no resistance to movement.

Thanks, I have a multimeter but no idea what I would need to connect it to or what I am looking for :-)

John.G

Have a look at the Mmeter photo and ensure the leads are connected as shown then turn the selector knob to the 500 or 600 scale near the voltage sign as shown, its a bit like V~ and not the other V sign which looks a bit like V=. Trace the cable from any one of the actuators on the zone valves until you come to a junction box, you should see 4 wires (from this actuator) a orange and grey and brown and blue. place the red lead on the orange terminal and the black lead on the blue terminal and if it reads 0 volts then the actuator is OK do the same with the other actuator. To test that the M.meter is on the correct scale, put the red probe on the grey wire and the black probe on the blue, you should read 230V. As in post #1 ensure neither zone calling for heat and actuators closed.