HELP: Heating on the blink

[emeyedeejay]

I'd like some input from the pros on this site please...

Firstly - I know (or at least I think I know ) this will require professonal assistance - still I like to know what;s going on in situations like this so I'm not led down the garden path as it wee

Some facts...

1. I've lived in this house for 15 months and have never looked at or thought about how our CH and HW work - they always just "have"

2. We have 2 central circuits in our house - 1 upstairs and 1 downstaris. Both are controlled by room stats. Based on some reading I've done and by visual inspection I assume ths means we have 3 x 2 port valves (1 for each heating circuit and 1 for HW)

Last night everything was working. I usually leave the room stats on just under 18 degs overnight. This morning downstairs felt much cooler than I would have expected.

Felt the rads - cold as a very cold thing! Checked the room stat - it was set above the tem that it should have engaged. I tunred it down, heard the disengagment click - turned it back up heard the engagement click.

What I did NOT hear was the familiar "clockwork" noise coming from above the boiler.

I'm guessing this is a problem with the 2 port valve that controls the downstairs CH.

I removed all the covers etc. above the boiler to reveal the valves, pipes etc. just to have a look.

I got on the web and found out some info re the valves I have - they are Honewell V4043H valves. I read that I could rmove the silver cover and that would show the motor.

I removed the cover and had a peek.

After a bit more reading, I'm fairly convinced it's the motor that is either stuck or knackered. I'm led to the conclusion by the following ...

If I slide he vlave switch to manual (which I assume opens the valve) and press in the visible microswitch, the boiler engages and lights and water flows to the rads.

What doesn't appear to be happening is that the motor is doing anything at all when th room stat engages. I can see the tab that is supposed to make contact with the microswitch but it doesn;t move at all...

Is my fault diagnosis correct? COuld this be an electrical fault?

Is this a case of having the motor repleaced? Or is an entire new valve required?

Long post - manythanks for taking the time to read it

 

[chrishutt]

You done well! Almost certainly the fault is a failed synchron motor, which is the silver metal cylindrical thing with two wires that sits under the cover of the valve. You can buy these for around £10 (try BES) and fitting is quite simple, providing you observe basic electrical safety (turn off power!).

In the mean time, if you leave the valve in the MAN position it will remain open but not operate the system itself, but you can operate the whole system via the upstairs stat/timer.

 

[ChrisR]

Is my fault diagnosis correct?

Probably

COuld this be an electrical fault?

Anything's possible - faulty thermostat say. Check by checking for mains on the wires to the motor (blue/brown on the wire to the valve)

Is this a case of having the motor repleaced?

Probably

Or is an entire new valve required?

You should be able to change just the head (silver part), which can be required if the mechanics inside go wobbly.

 

[emeyedeejay]

You done well! Almost certainly the fault is a failed synchron motor, which is the silver metal cylindrical thing with two wires that sits under the cover of the valve. You can buy these for around £10 (try BES) and fitting is quite simple, providing you observe basic electrical safety (turn off power!).

In the mean time, if you leave the valve in the MAN position it will remain open but not operate the system itself, but you can operate the whole system via the upstairs stat/timer.

Many many thanks for the prompt reply...

I was wondering if I could in the meatime run with the failed valve in Manual. I assume if I do thiat then whenever the boiler is firing, the downstairs rad will heat up (as the valve with the failed motor is now permanently open).

You say it's a simple replacement job. I'm fairly competant when it comes to DIY but have always shyed away when electrics are concerned. That said, it sounds like it's a motor connected to 2 wires - how hard can that be!

You also mention BES - what would that be exactly?

Thanks again - at least I know we won't be cold in the meantime - the temperature was dropping fats downstairs

 

[emeyedeejay]

Is my fault diagnosis correct?

Probably

COuld this be an electrical fault?

Anything's possible - faulty thermostat say. Check by checking for mains on the wires to the motor (blue/brown on the wire to the valve)

Is this a case of having the motor repleaced?

Probably

Or is an entire new valve required?

You should be able to change just the head (silver part), which can be required if the mechanics inside go wobbly.

Thanks for the ChrisR ..

Is there any other way of determining if this is a possible faulty room stat?

I don;t know what you mean by "check for mains" on the wires going to the motor - do you mean with a circuit tester? Don't have one of those - scared of electrics

One additional thing I'd like o ask ... in what order do the switches work to get the boiler to fire ...

Doe the room stat close a switch that activates the 2 port valve motor which then turns and closes the micro switch to tell the bloier to fire?

Thanks for all the input folks...

 

[emeyedeejay]

Looks Like I need this right?

http://www.bes.ltd.uk/products/112.asp

 

[ChrisR]

I don;t know what you mean by "check for mains" on the wires going to the motor - do you mean with a circuit tester? Don't have one of those - scared of electrics

Statistically cheaper to change the motor than pay someone to diagnose then.

Does the room stat close a switch that activates the 2 port valve motor which then turns and closes the micro switch to tell the boiler to fire?

Yes that's it.

The BES motors have had a couple of bad reviews recently - luck?

 

[emeyedeejay]

I don;t know what you mean by "check for mains" on the wires going to the motor - do you mean with a circuit tester? Don't have one of those - scared of electrics

Statistically cheaper to change the motor than pay someone to diagnose then.

Does the room stat close a switch that activates the 2 port valve motor which then turns and closes the micro switch to tell the boiler to fire?

Yes that's it.

The BES motors have had a couple of bad reviews recently - luck?

Thanks Chris - I'll order in a motor - at least I know for now I have a workaround.

Is there any thing that can be damaged etc. by leaving the valve in the manual open position for a period of time?

 

[emeyedeejay]

In the meantime, until a new motor is received ...

Can I swap the functioning motor on the 2 port valve from the hot water valve with the faulty one then leave the hot water valve on manual?

The house is really warm now with the downstairs heating not responding to the room stat.

 

[emeyedeejay]

The synchron motor has been replaced and the system is back to normal and functioning well...

Many thanks again to you all for your input!