Boiler concern.....again

mirand

[FONT=&quot]June 2012 I replaced my old boiler with a Vaillant combi Ecotec 837 plus “2” which was working fine from day one.

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[FONT=&quot]Nine months later I experienced on two occasions the problem of boiler not firing, and after several attempts displayed two error messages F28(29) & F54. As per the user-manual instructions this was resolved by re-setting the boiler and it worked fine after resetting.

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[FONT=&quot]The gas pipes in my house were 15mm running from the meter to the kitchen, two third are exposed and when fitting the new boiler the exposed part was replaced with 22mm from the meter till where it goes under kitchen floor (two thirds).
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[FONT=&quot]As it was a new boiler, I called Vaillant to check the cause. They advised insufficient gas pressure has caused this fault and that I should replace the remainder of the gas pipes supplying the boiler in my house i.e. the buried third. As Vaillant installation manual clearly indicates that the minimum gas supply size is 15mm, Vaillant failed to give me an answer to question if 15mm is not the correct supply size why is it stated so by their installation manuals?.
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[FONT=&quot]Boiler worked ok since May last year till three weeks ago when we started getting these error messages again and have to reset it several times before it fires up and work. [/FONT]

[FONT=&quot]Through the forum last year I learnt that with the Vaillant Ecotec 837 plus”2” there have been many reported problems in so far as their gas valves and I am wondering to whether this is what is causing the problem or do I have to upgrade the “buried” part of the gas pipes from 15mm to 22mm? as this will be a massive upheaval in terms of inconvenience and cost (this part is running under the kitchen floor). [/FONT]

[FONT=&quot]Has anyone been through something similar?
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[FONT=&quot]Thank you,
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penrhyn

Never heard of a Combi Boiler that can be supplied with a 15 mm gas pipe.

http://www.vaillant.co.uk/mediaarchive/2013/09/ecoTEC-installation-and-servicing-manual.pdf

Page 17, 837: 22 mm pipe.

Pincher

If you have high pressure at the gas meter, it could have worked.
I expect the pressure was borderline when it was first installed, then it went down, for all sorts of reasons:

1. General reduction for the whole area.
2. Neighbours installed more appliances.
3. You are cooking with all the burners on the gas hob.
4. Leak.

ollski

I suspect the engineer used it as an excuse to get out of the door on an intermittent fault. What figure did he say your working gas pressure was?

mirand

first eng reading was 15/16 and when vailliant sent another his reading was just 18mb

C_Mababejive

This needs a better diagnosis IMHO. It needs simultaneous pressure measurements at both the meter and the bolier when it is operating. I dont know what the vaillant install instructions say but im guessing it states that the supply must be such that there is a max pressure drop of 1mb between meter and boiler when the boiler is operating.

It is for the installer to ensure that the pipework is suitably designed and installed to ensure those criteria are met.

OTOH,it could be a simple flame detection issue..

C_Mababejive

In some areas,you'd be lucky to get 20mb on the network..!

Pincher

That's combis for you, gas guzzlers.
If you went for an 18kW boiler and a hot water cylinder, you probably would have been fine on the 15mm pipe.

penrhyn

Indeed, after much chat I got a nice simple Worcester Bosch R15i, added advantage of being a belt and braces system if the boiler fails I can stick the immersion on.

C_Mababejive

Pincher wrote: »

That's combis for you, gas guzzlers.
If you went for an 18kW boiler and a hot water cylinder, you probably would have been fine on the 15mm pipe.

Indeed..I am an advocate of high efficiency boilers linked to stored hot water systems. I beleive that combination boilers have been over sold and in many cases are inappropriate for many situations.

They are often sold on the back of dubious claims of higher efficiency.

They are often a strain on the gas and water networks and are wasteful of both IMHO.

Here at Mababejive towers i have a 12Kw boiler linked to a hot water cylinder which contains just enough to fill a bath. It provides excellent service at optimal cost and would happily run on much less than 20mb WP without a grumble.

ollski

In reality there won't be a problem running this 15 - 18mb.