Ideal Boiler not obeying controller

[docmel]

Hi

I have an Classic boiler + Siebe Lifestyle Controller.

Heating / Hotwater controlled by two motorised valve - Danfoss with what feels like a springloaded lever and "off and on" at bottom of valve

Few weeks ago the boiler stopped obeying the programmer - would not go off even when all programs at the controller were set to off.

I tried changing the controller for a new one but still no joy. The only way I can get the boiler to work is if I use the main on/off switch next to the boiler.

Can anyone guide me where to look next? - the whole system is about 4 years old

 

[ollski]

which is staying on?, the heating or hot water?...find this out and you will know which valve is faulty.

 

[docmel]

Thanks for the prompt reply

It seems that we get both hot water and heating at the same time.

 

[ollski]

Thanks for the prompt reply

It seems that we get both hot water and heating at the same time.

On two seperate motorized valves?

 

[docmel]

In the immersion cupboard - there are two danfoss valves - so in my complete ignorance I assumed that one controlled the heating the other the hotwater, but in thinking about it that cannot be the case can it? In my last house there was only one

Why would the system need two valves?

 

[kevplumb]

cos it's an s plan as opposed to a y plan

 

[docmel]

Ok - I have just seen a plan of an S system on the Honeywell Site (did a search for it) so I understand now.

Could it be one or both of these valves have broken? - or am I jumping to the wrong conclusion? - Its just in the last house we had a similar problem and it was the valve

 

[kevplumb]

sounds odd that both valves are duff
methinks electrical OLLSKI

 

[docmel]

Forgot to say - the room thermostat is set to 0 but the heating still belts it out

+++++++++++++++++++++++++++++++++++++++++++++++

ok..ok.. what is OLLSKI?/ - could this be the dreaded PCB I have been reading about?

 

[docmel]

just checked the valves

they say 'auto and man' not off and on.

The whole system is off now and one of the levers (heating) is in the man position - the hot water is on the auto position

 

[chrishutt]

Both valves should be in "auto" position. Are you sure the indicating lever isn't hooked into the slot that can hold it in the "man" position against the spring return? If this is not the case the valve must be jammed.

 

[docmel]

When I moved the lever it seemed very loose so I took the valve off the pipe and noticed that the motor was reluctant to turn.

I put my screwdriver in the slot where the flat tap would normally fit and applied just a little pressure - the thing then started to move of its own accord and returned to what seemed like the off position - I moved the tap to the corresponding position and put the valve back together again.

Switched on the system at the mains and nothing happened, which is ok, cus the heating controller was off - I set the manual override on the controller to off - turned up the room stat and the heating came on on - turned off the controller and it went off.

Cannot check the hot water cus that is still v. hot from the immersion heater

So it looks like that may have been the problem - still don't answer why the lever was loose - is this going to be a problem or can I ignore it cus I have an automatic system?

 

[chrishutt]

You can check the normal function of the lever on the valve that's working properly. When the valve is shut, the lever is in the "auto" position. You can manually open the valve by pushing the lever towards the "man" position against the spring. When you release it the spring pushes it back to the "auto" position.

However when the valve is in the open position (either because it's powered or jammed!) the lever will be loose. (The fully open position is some way beyond the "man" position in fact.) So your lever was loose because the valve had jammed open. Does that make sense?

There's a good chance that the valve will jam again, so it might be sensible to look around for a replacement (£40?).

 

[docmel]

Thanks Chrishutt

I will get one in, just in case

 

[ChrisR]

If it does it again, try undoing the top-holding screws a turn or so. Often they won't jam if you do that.

If you take the top (with motor etc) off the brass bit, look for any sign of leakage round the spindle. If there is any, you need a whole valve, but if it's dry you can buy the head by itself. Check the designation, there are two types of Danfoss valves on the go at once!