HW and CH switching on by itself (confused)

[jaretti]

Hi everyone,
This forum helped me a lot in the past, so that's why I think you will be able to help me again.

I can not understand what's going on with my boiler. It's switching itself on for no reason at all.

My water is set up to heat at night time for one hour, so by seven o'clock in evening it's sort of warm. However lately water us boiling hot all the time. I can hear boiler working at random times, and because radiators are cold I assume its hw.

My central heating is controlled by programmer + wireless thermostat. As I'm typing this programmer is in OFF position for both ch and hw, however boiler is working and my radiators are hot.

My setup is:
Danfoss FP715 programmer
Honeywell DT92E wireless room stat
Danfoss HSA3 3way valve actuator
grundfos pump
Danfoss thermostat type AT (on HW cylinder)
Baxi solo 2 40 PF boiler

Any thoughts would be appreciated.

Regards, Jaretti

 

[Agile]

The most common causes of that is a faulty or wet motor valve!

Tony

 

[jaretti]

Hi,
I believe valve operates fine, if I switch from ch to hw or vice versa valve changes it's position.

 

[Agile]

Yes, but the mere fact that it moves does not mean that the internal switches are working correctly.

But if you know better then me, feel free to repair it yourself.

I was only trying to help you.

I work as a heating engineer. What do you do?

Tony

 

[jaretti]

Checked with another 3 way valve + actuator but still having same problem.

Basically when everything switched to OFF on programmer boiler still kicks in. It doesn't stay on constantly, it will work and then stop again.

So something tells boiler to switch on, but what?

Any ideas anyone?

P.S. Didn't wanted to offend anybody, so sorry if my previous comment seemed rude, it wasn't my intention.

 

[Diyisfun]

Yes, but the mere fact that it moves does not mean that the internal switches are working correctly.

But if you know better then me, feel free to repair it yourself.

I was only trying to help you.

I work as a heating engineer. What do you do?

Tony

A bit harsh for you, you are normally the placid one.

 

[jaretti]

Hi all,
So since my last post I have replaced 3 port actuator AND put new Honeywell programmer. Called electrician who tested everything and everywhere and he couldn't find any faults whatsoever.
It still happening, boiler completely disregarding thermostat and programmer. When electrician was here everything was running OK, so that didn't help him either.
Everything might work alright for a day or so and then in the middle of the night or day I will hear boiler starting up, working for a few minutes then switching off, switching on again after 5 minutes and so on...
Electrician reckons that it have to be something wrong with boiler, but I dread to think how much it might cost me.
Can all you good people share your thoughts with me please, I would be very grateful.
Regards, Jay

 

[Agile]

A good heating engineer is better than an electrician. They usually dont have any diagnostic skills on heating systems and just change parts.

You need to know if there is any power being applied to the call for heat terminal on your boiler.

And if so where its coming from.

Tony