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Topic Title: GlowwormMicron 60ff
Topic Summary: Boiler runs constantly Glowworm Micron 60ff
Created On: 20 December 2012 05:05 PM
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 20 December 2012 05:05 PM
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123paulsellsall

Posts: 1
Joined: 20 December 2012

We are electrical and have been called to a Glowworm Micron 60ff based around a Y plan, the only difference being the pump is not off the wiring centre its off the terminals in the boiler for the pump run on.
The boiler has a perm live sw live neut & earth and pump live and neutral.

Problem we have inherited after valiant have been out to swap, programmer & Mid Position valve (was a drayton now they have installed a honeywell) and a new cylinder stat. Think they were fumbling in the dark for a soloution,

Problem was originally that client had no control of the heating, valiant came via home serve and explained to client the valve had stuck, replaced the motor in the mv only and freed it up.

Problem returned, they come out again and change the vale complete from a drayton mid pos to a honeywell, since then no control over boiler which runs constantly unless it switches off on its own stat. no room stat control no cyl stat control

We have stripped the wiring and proved it all out and the only way we can stop this happening is if we disconnect the pump from the boiler control PCB and connect the pump into the boiler switch wire in the wiring centre. I realise this stops the pump working in its run on state but once we have done this the system works absolutely fine ?. all stats work etc valve operates no issues.

Does anyone know of a problem with these boilers, apparently some time ago some Woster boilers had a similar issue and it was solved with a capacitor ?? Seems to me like a back feed when the pump is in situ.

Can anyone assist.
 20 December 2012 06:03 PM
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slittle

Posts: 3507
Joined: 22 November 2007

I'm sure you've checked but there is no chance of a second "feed" to the pump is there that is then backfeeding the boiler ?


Stu
 20 December 2012 10:52 PM
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AdrianWint

Posts: 262
Joined: 25 May 2006

Another classic is the frost stat.... seen a few where the boiler is in the garage with a frost stat next to it.

When the weather goes cold, the garage drops below 5deg & the frost stat overrides & fires the boiler .... all well & good, but, since there is no radiator in the garage it never warms up ..... so the frost keeps calling for heat until the weather warms up!

Do you have a similar problem, perhaps?

Adrian
 20 December 2012 11:11 PM
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Rulland

Posts: 461
Joined: 11 April 2008

Which is why the frost stat (which is supposed to prevent pipe work etc from freezing) if placed in an outbuilding with no rads, should be positioned above/close to the pipe work-ie the pipe work warms up-thus wont freeze-stat then cuts boiler off until required to prevent pipe damage again!.

-------------------------
Those who make no mistakes do very little work!!......
 20 December 2012 11:34 PM
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Jaymack

Posts: 4638
Joined: 07 April 2004

I had a similar problem a few days ago when the temperature was around 5 degrees C. The boiler was intermittently firing for short periods, when not called for, from the controller. This went on for a couple of days, I did suspect a frost thermostat somewhere, but couldn't find one. The temperature is now higher and the boiler is now behaving itself.

It's a Worcester, Model 19/24CBi.

Regards
 21 December 2012 07:09 AM
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kirchoffs

Posts: 180
Joined: 08 February 2010

If it is the frost stat and boiler is in the garage with frost stat adjacent make sure low limit pipe stat is fitted too the return pipework,


Regards Dominic
 21 December 2012 07:49 AM
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colinhaggett

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Joined: 08 July 2004

Some boilers come with an internal frost stat!
 21 December 2012 08:04 AM
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colinhaggett

Posts: 364
Joined: 08 July 2004

I take it you removed the switch live from the boiler and it still ran? Them it's most likely the circuit board at fault or back feed from the pump, all pretty easy to work out. Aways thought boilers had a relay for the pump so even a back feed shouldn't fire the boiler.
 21 December 2012 11:17 AM
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AdrianWint

Posts: 262
Joined: 25 May 2006

Originally posted by: Rulland

Which is why the frost stat (which is supposed to prevent pipe work etc from freezing) if placed in an outbuilding with no rads, should be positioned above/close to the pipe work-ie the pipe work warms up-thus wont freeze-stat then cuts boiler off until required to prevent pipe damage again!.


I concur ... another solution is to connect a pipe stat inline with the frost stat to shut the system down again when the return water to the boiler is above about 50 deg. or so ..... but try explaining that to a plumber!
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