CH won't fire. HW works fine. Any ideas?

[benraz69]

Hi all,

I've changed the batteries & re-synced the RF roomstat, which all did as it's meant to. Other than that, nothing - no lights on the boiler, pump doesn't kick in, no movement on the motorised valve (The HW works fine - boiler, pump, etc). Any ideas?... My system is as follows:

• Baxi Solo 24HE conventional boiler
• Honeywell ST9400C programmer
• Honeywell HCW80 roomstat RF sender
• Honeywell R6660D roomstat RF receiver
• Honeywell V4043H1056 two port valve (x2)
• Honeywell sundial plan wiring centre
• Grundfos Alpha2 L 15-60 130 pump

Thanks, Ben.

 

[seco services]

Motor or micro switch failure on zone valve.

 

[benraz69]

Motor or micro switch failure on zone valve.

Thanks, is there any way I can tell whether it's the motor or microswitch at fault?

Or should I just replace the cheapest component first & see if that works?

Also, until it's fixed, is it okay to manually open the two port to provide me with some CH while the HW is on?

 

[bolshy]

Open it manually with the CH selected to on, demand on roomstat, hot water off. See if it fires the boiler. Although, if it doesn't move when there's a demand for CH, then it's probably the motor.

 

[benraz69]

Open it manually with the CH selected to on, demand on roomstat, hot water off. See if it fires the boiler. Although, if it doesn't move when there's a demand for CH, then it's probably the motor.

Hi, the boiler doesn't fire when I open it manually either...

I've taken the cover off the two port & there's definitely no movement when the CH is switched on. However, if I push the brass arm across to the microswitch internally, it fires, pump kicks in too.

Does this point to the motor?

 

[45yearsagasman]

It will be the motor. If you have the means then you can test to see if there is 230v to it just to be 100% sure. New motor readily obtainable and simple to replace. Work safe.

 

[benraz69]

It will be the motor. If you have the means then you can test to see if there is 230v to it just to be 100% sure. New motor readily obtainable and simple to replace. Work safe.

Unwired the motor & did a continuity test using a multimeter. Each time, it quickly flashes up a reading somewhere between 500-2000, then goes back to 1 very quickly. No audible beep... Testing the multimeter on other metal objects produces a beep every time & a 1-500 reading. I guess it's the motor then?

(Apologies if I'm stating the obvious, it's just that I've rarely used a multimeter before & am unsure if the readings are relevant)

 

[Agile]

Little point in having a meter if you cannot use it!

The valve motors have a resistance of about 2200 ohms.

Yours is probably open circuit !

Tony

 

[benraz69]

Little point in having a meter if you cannot use it!

It was a freebie. A mate gave it to me when he bought a new one. Thought it might come in handy one day.

The valve motors have a resistance of about 2200 ohms.

Yours is probably open circuit !

Tony

D'oh! Yeah, didn't think of that

Anyway, turns out it's not the motor, or in fact the two port valve at all... Just popped out & bought some bits - changed the motor, nothing. Changed the whole head/actuator, still nothing!

What I should try next?

 

[Agile]

It will be the motor. If you have the means then you can test to see if there is 230v to it just to be 100% sure. New motor readily obtainable and simple to replace. Work safe.

As Pete said a while ago you should have tested to see if 230v was being provided to the valve motor ( before changing it ).

Timeclock or roomstat I expect now!

Tony

 

[benraz69]

As Pete said a while ago you should have tested to see if 230v was being provided to the valve motor ( before changing it ).

Yeah, I think I misinterpreted that ...

Anyhow, I got my money back on the motor & head/actuator, no probs.

Timeclock or roomstat I expect now!

Tony

After a quick lesson on how to use a multimeter from my mate, I found that there was no live coming from the "CH on" programmer wire. Took the facia off the programmer, and found that enough dust/grit had dropped down between the facia & backplate, that it'd broken the contact between the CH pin & wire (I'm currently redoing the ceiling in that room). A quick clean & job done

Thanks to all who posted