Heating only when sliding this switch

[homertimpson]

Had a problem for the past 2 nights with my central heating - water is OK, but heating is playing up.

Started Friday night about 7pm when the missus complained the house was 'cold' - turned the room thermostat up - but the rads did not get warm.

I went to the integral garage and noticed that every light on the Baxi Solo 2 boiler was out - and I wasn't able to get them to come back on.

I then 'advanced' the hot water, all the lights came on and the rads warmed up within minutes. However, as soon as I switched the water off the whole system went off. I could get the rads to go - but only by having the water on as well - which is not supposed to be necessary.

I looked inside the water tank cupboard and found this white controller box Boiler7 pic
It has a slider button on the side. With the heating on and the water off - no rads - but , when I slid this button you could 'feel' it was opening a valve - and by the time I got to the garage the boiler had fired up again.

Same again today - timer setting came on this morning [water & rads], but when the water timer went off so did the boiler. I went back to the cupboard, slid the switch again, and the heating came back on.

Sorry for the long post - but it is the only way I can explain it

This controller box must switch a valve that directs water between the rads and the water tank as well as 'instructing' the boiler to fire up?

What could be causing this breakdown?

All help appreciated.

Regards

Homer

 

[chrishutt]

You seem to have understood the workings of your system and diagnosed the fault quite well. The motorised valve is a mid position 3 port valve. They often develop problems - either the synchron motor inside fails or the micro switches fail. I'm not up to working out which at the moment but you'll find lots of threads on this if you search on the terms in bold above.

 

[homertimpson]

Thanks for that - I just got a new digital camera and it certainly helped to show my problem - I would have struggled to describe it without that aid

Will now get off searching

Thanks again

Homer

 

[dal5band]

1 You may be able to hook the lever in the on position for central heating - have a closer look.

2 On some valves you change the actuator (the white box) without the need for any plumbing. what's the make & model on the box - it looks as though the top bit comes off.

 

[homertimpson]

ACLDrayton Lifestyle Mid-Position Valve
22mm 679H340-30L0

There was another small lever at the back of the box - I tried to move it and it broke off

Having taken the white cover off, I then noticed a silver marker with the letters H - M - W where this slider was situated.

At a guess I'd say H - Heating, M - Mix, W - Water?

I'd say the slider was on H when I tried to move it - where it ended up when it broke is anyones guess

I had a quick look on Ebay and found this Head only and it looks very similar. Mine does not say MA1 - but the house is 7 years old and this may be the 'newer' model.

Would fitting this be a case of electrics off and a straight replacement - doable for a diy man like myself?

Homer

 

[dal5band]

Need to make sure the mechanical valve in the water is ok. - it's not gunged-up or stuck or rubber perished. Not sure how this particular model works.

 

[homertimpson]

I just realised that I am paying for a British Gas maintenance contract on my c/h system

All parts/labour

Up to 2 call-outs per year without affecting premiums

I've never use it until now

Thanks for putting up with me guys

Homer

 

[dal5band]

Do-oh

 

[homertimpson]

Phonedf BG Tuesday night - arranged for Thursday pm [anytime between 1-6pm].

M-I-L kindly agreed to house sit

Engineer arrived 1.20pm

I called just after he arrived and explained mid-position valve scenario.

He was genuinely pleased I'd diagnosed the fault for him. [probably meant he could massage his time sheet for an extra long tea-break ]

New mid-position valve duly fitted - he said it was the 'better' type - top half could be unclipped and replaced without the need to touch the plumbing side.

Happy bunny now

Must remember 2 things now:

1. Always search forums before making posts
2. Always ask if you have a service contract tucked away in a drawer

Homer