Cylinder / Boiler wont turn off

[D4mo]

Hello everyone,

First time poster here. I'm hoping someone might be able to offer some advice with a problem that's started with my home boiler.

I have an Ideal ICOS HE15 boiler, a Tribune 150 litre indirect cylinder and a Danfoss FP715 Si two channel programmer.

My hot water is set on a timer to fire on in the morning (which it does) for one hour but the boiler and cylinder carries on working after the hour is up and will not turn off. The controller would have a light lit when the hot water's on and this is turning off after the hour (which is normal).

If I turn the boiler off, the cylinder carries on working.

Factory resetting the controller doesn't seem to stop the cylinder working.

If I turn off all the electrics to the heating system the cylinder will turn off.

If I turn the power back on, whilst the boiler is turned off, the cylinder will start up again.

If I leave the power off for a couple of hours and then factory reset the controller, this then stops the cylinder working. I can then turn the boiler back on without it firing up again.

It will then be like groundhog day the next morning when the hot water kicks in again.

I've uploaded a photo of the cylinder that may assist but please let me know if you require any further information.

Many thanks,
Damien

 

[flameport]

Likely that the motorised valve for the hot water is sticking, or the switch inside the valve is sticking in the on position.

 

[ianmcd]

what he said

 

[D4mo]

Many thanks both. I guess I'll contact a plumber to get it replaced.

 

[Hunch1969]

Hi I've got a similar issue to above. I've just had a brand new bog standard boiler installed (Vaillant - ecoTEC Plus 424). Not sure of the technical name of the system I have, but its old school with a storage tank and expansion tank in the loft and absolutely no trendy wifi technology in the loop .

So even when I have the controller turned off so that in theory no water or heating should be on, the boiler keeps going heating up hot water. As suggested above the installer suggests it could be the valve between the heating and hot water supply being sticky or possibly the thermostat on the hotwater cylinder? Does this make sense? In my simple brain I kind of thing if you have set both the central heating and hot water to not come on via the controller then nothing should over ride it? I assume the cylinder thermostat thing is more for making sure the water inside is at the right temp once water is being heated and would cut off/turn on the boiler to keep to a designated temp, but it doesn't make sense to me why that would override setting the programme to off for both water and heating.
Same with the motorise value, I can see how that could be an issue in general, particularly as we just had a power clean as part of the installation so might have some crap caught in the value, but in my simple head, it shouldn't come into play if the both water and CH is off? I assume I'm just ignorant about how these things work, but thought I'd double check.

 

[CountryFan]

It’s either the valve motor, as the actuator (powerhead) sends a switch live to the boiler when it’s motored open, so if sticking will send voltage to the boiler. That or the link has been left in by the installer.

 

[Hunch1969]

It’s either the valve motor, as the actuator (powerhead) sends a switch live to the boiler when it’s motored open, so if sticking will send voltage to the boiler. That or the link has been left in by the installer.

Thanks for the really quick response and explanation. So in very layman terms, if i kind of understand it, if the actuator isn't moving correctly due to the value sticking then it keeps sending voltage to the boiler and the boiler caries on heating the water and will do until the actuator stops sending a live signal?
In which case, as a test should I be able to take the actuator off the valve and assuming there isn't an issue with the actuator it should go into the closed position when the water is cycled off and stop sending a signal? if that does happen then I guess I need to get a new valve installed?

PS what do you mean by "the link has been left in by the installer" is that some sort of testing setup

 

[CountryFan]

then it keeps sending voltage to the boiler and the boiler caries on heating the water and will do until the actuator stops sending a live signal?

Yes, it does this because of a sticking microswitch, located in the actuator

In which case, as a test should I be able to take the actuator off the valve and assuming there isn't an issue with the actuator it should go into the closed position when the water is cycled off and stop sending a signal?

No, this won’t work, would need to test for voltage

if that does happen then I guess I need to get a new valve installed?

Or actuator

PS what do you mean by "the link has been left in by the installer" is that some sort of testing setup

No, boilers often come with a link fitted so they can be used for central heating until a thermostat can be fitted.

 

[Hunch1969]

Yes, it does this because of a sticking microswitch, located in the actuator

No, this won’t work, would need to test for voltage

Or actuator

No, boilers often come with a link fitted so they can be used for central heating until a thermostat can be fitted.

Thanks for all the information. I really appreciate it .