Boiler Gas Pressure suddenly Unsafe??

tjamesbo

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My 40Kw Baxi Ecotec Combi developed a faulty diverter the other day and as its on a repair contract the Baxi Man came round to repair it At the end he said that the gas pressure was on the low side slightly under what it should be ( maybe 15 instead of 17? Millibars possibly? not sure I accurately remember the numbers ) and said he had to put a notice on it "Danger Do not use " he said operationally it was fine everything else was within limits but by the book he had to put the notice on it ....... he left it running and operational .
Now the Boiler gets serviced every year since about 2010 by Gas safe engineer several different ones over the years ( and even one who did a landlord gas safe certificate on it as he got confused about my rental properties ) and has been attended to on about 4 or 5 occasions by a Baxi Engineer the last one as recently as December 2020 and Never on any of those occasions has there been any issue reported so why am I now getting this notice ? He said I should alter the Gas feed from the meter from 22mm to 28mm and take a straighter route . What I cant get over is nothing has changed over the last 11 years except perhaps their standards is this the old industry creating work ? If it really is dangerous then fair enough ,but what if the street gas pressure drops from time to time should they all be turned off
Its irritating hence the rant I'm determined to find out exactly what the issue and the potential risk is and how this situation has suddenly arisen
Any gas engineers or someone with any understanding of this ?
 

chic0821

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Similar thing a few years ago. New kitchen being installed, checking the cooker was working, installer said pressure was low & had to put a notice do not use on it, but said we could not use any gas, ie central heating boiler. I phoned the gas board, this was about 7pm, guy arrived about 30mins later, checked everything. Valve on the meter was faulty, 5 mins to change. Clean bill of health. We never thought anything was wrong, but if it had been slowly degrading over a period of time you would never notice.
 

markjay

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Similar thing a few years ago. New kitchen being installed, checking the cooker was working, installer said pressure was low & had to put a notice do not use on it, but said we could not use any gas, ie central heating boiler. I phoned the gas board, this was about 7pm, guy arrived about 30mins later, checked everything. Valve on the meter was faulty, 5 mins to change. Clean bill of health. We never thought anything was wrong, but if it had been slowly degrading over a period of time you would never notice.

As above - the issue might not be with the boiler itself, but with the car supply at the premises.
 

Petrol Pete

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As they build more and more houses around my way I am convinced our mains water and gas pressure is slowly dropping to whatever the lowest is allowed. And when I did major work on this old place 15 years ago on a whim I ran a 22mm gas pipe in the whole length of the house all the way to the kitchen . glad I did now.
 

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What I cant get over is nothing has changed over the last 11 years except perhaps their standards is this the old industry creating work ? If it really is dangerous then fair enough ,but what if the street gas pressure drops from time to time should they all be turned off

What has happened over the last 11 years and more is that most homes have removed system boilers and installed combi boilers that have a much higher peak gas usage. When they are all on full fire at peak times like first thing in the morning, gas pressure can fall because the infrastructure isn't quite up to supplying the demand. I can see this by the flame strength on the gas hob without getting a manometer out. Gas pressure varies all the time according to demand. Ideally the distribution pressure should always be higher than the regulated set pressure at the gas meter but if it isn't you see the effects. I'm not sure why marginally low pressure should be a safety concern but perhaps any gas engineers among us will explain.
 

Atavus

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The risk is incomplete combustion or explosion. Not that a bit of low pressure is any guarantee of those occurring.

It’s quite a powerful boiler, like a lot of combi boilers. There will be a spec from the manufacturer and you are in the ‘at risk’ zone. He has probably checked for CO/CO2 and finds those to be ok.

None of that is a qualified opinion.
 

Piff

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Standards change over times.
I had a balanced flue gas boiler where the exhaust & intake were directly behind the boiler under a car port. Changed for a fan flued boiler where the exhaust & intake were above the boiler again under the carport.
The carport had a downstand beam at one end but was open at the other end. Perfectly legal at the time of installation.
A couple of years later following a gas board visit they hung a "do not use" label on the boiler as the flue was non compliant. Seems that there had been an issue in a Scottish tenement building where fumes had been trapped between downstand beams.
Couldn't happen at mine as the carport had no downstand beam at the rear, but the rules are the rules.
One solution was to fit a 90 degree angle on the flue pipe which would have taken the flue gasses below the level of the downstand beam, still below the carport roof but now directly on the heads of visitors :doh:.
I chose an alternative to extend the flue out of the carport.
 

GP801

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We recently had a new boiler when the kitchen and utility room were redone. Installer found the pressure at the meter was fine but the drop by the time it reached the boiler was too great to sign it off. Pipework was to an older narrower standard. For some reason best known to the builders it had a very convoluted run. The solution was to reroute a section of pipe to take out a 90 degree bend and fit a 2 meter length of wider pipe. Hey presto the pressure was now within limits.
 
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tjamesbo

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I think I'll get my gas engineer to come and check the pressures at the meter and boiler static and working and take it from there its not a big problem to run a new 28mm pipe on a straighter run
 

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