lack of cross-bonding causing shutoff?

[daffs]

Hi,
My Worcestershire Bosch Greenstar 24Ri is still shutting itself off occasionally.
Y plan, micro bore.
Restarts immediately with a reset & after 4 WB visits still no joy.


But... This is clutching at straws now...
I heard about cross bonding & the WB manual says "all pipes must be cross bonded".
However I can't see any sign - I presume the clamps would be close to the boiler.
With the boiler casing earthed via it's supply connections &
with all the pipes coming to/from the boiler on a metal frame as part of the boiler surely this forms the cross-bonding?
Is it that the earth via the mains connection is not sufficient?

Can't think why WB haven't spotted this if this is the case, oh and i did use a corgi installer of course.

I mostly suspect (having removed one radiator for decorating) that
the original powerflush wasn't thorough enough.
Although the radiators & hot water seem fine in practice.
Anyway if the air temperature rises next week end I intend draining/hosing all radiators/restorer and refilling.
So hopefully that's the real problem - just thought I'd ask so i'd be ready for the next WB visit.

Thanks

 

[gremlin16]

The lack of cross bonding should have no effect on boiler operation.
(does not mean the wiring is to current standards though)
Are you sure the external wiring is ok?

 

[petit_pablo]

Crossbonding would have no bearing on boiler operation im afraid. Your problem lies elsewhere.

 

[daffs]

Hi,
Belated follow up on this.
WB reckon the fault is with the three port (mid-position) valve & were able to repeat the fault.
I guess it's electrical spikes, as they jut flicked CH/HW on/off rapidly and the boiler shut down.
They say they have heard of this problem with "this type" i.e. Drayton - same as the screw-fix catalogue part, but had not seen in with the Honeywell parts.

The system is less than a year old but having become exasperated with my installer who stalls more than the valve itself I thought I'd replace it myself.

Q1. If I buy the honeywell part can I just interchange the heads?

Q2 If I have to replace it all can save draining down if I use the service valves that are on the pump and on the feed from the F/H tank?
The pump and valve are in the airing cupboard and in line with the tank.

Q3. Are WB correct or should I just get another one of the same type and assume this one is plain faulty?

Thanks

 

[gas4you]

Yes you can replace just the head. As it seems to be an electrical fault it sounds as this is all that is necessary.

Wouldn't take your installer any more than 30 mins to do this and you wouldn't have to pay for the head as it is under warranty.

 

[LUNAT]

HI

IDEAL combi two months old boiler which would not fire.so my mate called engineer from ideal because it was under guarantee and the fault was with the main earth bonding.because the main earth bonding was not connected to the gas pipe the boiler was not firing up .I still do not understand for this but earth wire was connected and boiler came ON straight away.WEIRD.

 

[EliteHeat]

HI

IDEAL combi two months old boiler which would not fire.so my mate called engineer from ideal because it was under guarantee and the fault was with the main earth bonding.because the main earth bonding was not connected to the gas pipe the boiler was not firing up .I still do not understand for this but earth wire was connected and boiler came ON straight away.WEIRD.

That's Ideal boilers for you

 

[Agile]

To the OP.

You could apply some temporary cross bonding with a set of car jump leads between gas an mains water and between mains water and one Ch pipe.

If its mains borne spikes getting into boiler circuit then that could quite possibly be the cause.

Ideal boilers mostly use a very good inductance based mains filter but Worcester just use a capacitance across the mains supply and a voltage surge supressor after the fuse. That does not give very good filtering of small spikes.

Tony

 

[ollski]

HI

IDEAL combi two months old boiler which would not fire.so my mate called engineer from ideal because it was under guarantee and the fault was with the main earth bonding.because the main earth bonding was not connected to the gas pipe the boiler was not firing up .I still do not understand for this but earth wire was connected and boiler came ON straight away.WEIRD.

Ideals are a pig for a correct earth, particularly the isar/ icos/ istor.