Huge gas pressure drop between meter and boiler. Help!

[davecon70]

Just re read the OP, I had failed to spot it was only fitted a year ago.
How do you know it was 20mb at each end? I may be mistaken but, unless the installer fitted a test point BEFORE the isolation valve, 20 mb would be impossible to achieve as the Vailant test point is on the multifunctional control valve, which itself will incur a 1.5mb drop.

Ideal fit a test point on the isolation valve whereas, I believe, Vailant don’t.

Did you SEE the test?

Was this an independent or , eg, BOXT?

iI would love to hear it was BOXT, tbh.

I would be getting the original installer back. Near in mind that if it was BOXT, Worcester either own it, have shares in it, or there is some other arrangement. I am surprised that the engineer did not make a bigger fuss of , possibly, undersized pipe work - unless they are banned from criticising BOXT?

hi there. No he wasn’t BOXT- he’s independent and certified gas safe engineer. The boiler was installed 2 years ago to replace a 12 year old Vaillant. Definitely no isolation valve on a Valliant.

last year I didn’t see the test, only that everything was ok. This year the nanometer (if that’s what it is called) showed very different readings so Valliant was called to see if the boiler was at fault. It wasn’t. From a Vaillant perspective the 13.5 millibar satisfied their minimum requirements but the plumber is concerned about the pressure drop.

It always seems to be bad news with the boiler although it also transpired that the plumber didn’t fit it as per the instructions as it only has 90mm clearance from the mega flow below and it should be 180mm. That wouldn’t affect the pressure drop.

not quite sure what to do but the plumber is back on Monday.

 

[davecon70]

Just re read the OP, I had failed to spot it was only fitted a year ago.
How do you know it was 20mb at each end? I may be mistaken but, unless the installer fitted a test point BEFORE the isolation valve, 20 mb would be impossible to achieve as the Vailant test point is on the multifunctional control valve, which itself will incur a 1.5mb drop.

Ideal fit a test point on the isolation valve whereas, I believe, Vailant don’t.

Did you SEE the test?

Was this an independent or , eg, BOXT?

iI would love to hear it was BOXT, tbh.

I would be getting the original installer back. Near in mind that if it was BOXT, Worcester either own it, have shares in it, or there is some other arrangement. I am surprised that the engineer did not make a bigger fuss of , possibly, undersized pipe work - unless they are banned from criticising BOXT?

hi there. No he wasn’t BOXT- he’s independent and certified gas safe engineer. The boiler was installed 2 years ago to replace a 12 year old Vaillant. Definitely no isolation valve on a Valliant.

last year I didn’t see the test, only that everything was ok. This year the nanometer (if that’s what it is called) showed very different readings so Valliant was called to see if the boiler was at fault. It wasn’t. From a Vaillant perspective the 13.5 millibar satisfied their minimum requirements but the plumber is concerned about the pressure drop.

It always seems to be bad news with the boiler although it also transpired that the plumber didn’t fit it as per the instructions as it only has 90mm clearance from the mega flow below and it should be 180mm. That wouldn’t affect the pressure drop.

not quite sure what to do but the plumber is back on Monday.

 

[davecon70]

It was installed 2 years ago, and recently serviced by the plumber that installed it. We don't know who serviced it last year, when the 20mb at meter and boiler were obtained, but it's a fair bet it was the same guy. If the installer failed to meet the 1mb drop reg perhaps he should be pulled up, but unless Gas Safe or somebody hears about it, I don't suppose anything much will happen.
Treating it as a "come across" job, where excessive pressure drop is only NCS, presumably it's OK.


As I understand it, pressure after the meter should be 21+/-2mb, so 17mb would be non-compliant and the gas supplier should rectify it. But if it did fall to 17mb, with pipe drop 20-13.5 = 6.5mb, so something like 11mb at the boiler, the boiler output would be down (unless it has a low-pressure cutout, I wouldn't know)

it was the same plumber\GSE that installed it and serviced it last year. Do you think it’s worth calling British Gas?

 

[Harry Bloomfield]

I don't think he was suggesting one dies that with gas, he was talking about cars.

Though to be honest my experience with both suggests I'm better off doing both myself.

Although as luck would have it I have since found a very good gse that is able to think for himself and fix issues without just chucking parts at it, which is a rare occurrence.

Still trying to find a decent mechanic that has retired...

I was referring to cars, but my comments apply almost universally to all such domains, but not entirely their fault - they are often not able to witness a problem in person, so they sometimes have to depend on the customes sometimes vague symptoms and time is money, they often cannot sit their to see if their guess at the fault, fixed the problem.

I generally fix most things myself and have always done so, made easier by the likes of Google for back up.

 

[oldbutnotdead]

it was the same plumber\GSE that installed it and serviced it last year. Do you think it’s worth calling British Gas?

No. It bodes well that your plumber is concerned and returning Monday. In the meantime, what are the sizes and lengths of the supply pipe from meter to boiler (it is possible that your plumber was naughty on the install, didn't upgrade the supply pipe and is now looking to cash in. I could of course be doing him a great disservice there...but if you can share those pipe sizes and the exact boiler model @fixitflav has already offered to do the sums....

 

[davecon70]

No. It bodes well that your plumber is concerned and returning Monday. In the meantime, what are the sizes and lengths of the supply pipe from meter to boiler (it is possible that your plumber was naughty on the install, didn't upgrade the supply pipe and is now looking to cash in. I could of course be doing him a great disservice there...but if you can share those pipe sizes and the exact boiler model @fixitflav has already offered to do the sums....

its an eco tec plus 630. As you can tell I’m out my depth here but looking T the boiler feeds it a 15mm pipe going in and big old pipe pipe at the meter. Looks almost double the thickness. The gas feeds the cooker (5m away on same floor) and the boiler is on the first floor and got to be at least 13m from the meter. Not sure if that helps?

 

[oldbutnotdead]

its an eco tec plus 630. As you can tell I’m out my depth here but looking T the boiler feeds it a 15mm pipe going in and big old pipe pipe at the meter. Looks almost double the thickness. The gas feeds the cooker (5m away on same floor) and the boiler is on the first floor and got to be at least 13m from the meter. Not sure if that helps?

Yes that's helpful. If I've read the manual correctly, at max output it can use 3.2 cubic metres of gas per hour so that's one figure. The big old pipe from the meter (copper hopefully)- can you see what size it is when it goes into the floor and when it comes out? Quite important to be accurate on the size- big difference in pressure drop between 22mm and 28mm. Last one- how long is the length of 15mm from boiler to old (larger bore?) pipe, or does the 15mm vanish under the floor

 

[davecon70]

Yes that's helpful. If I've read the manual correctly, at max output it can use 3.2 cubic metres of gas per hour so that's one figure. The big old pipe from the meter (copper hopefully)- can you see what size it is when it goes into the floor and when it comes out? Quite important to be accurate on the size- big difference in pressure drop between 22mm and 28mm. Last one- how long is the length of 15mm from boiler to old (larger bore?) pipe, or does the 15mm vanish under the floor

looking at the old pipe it starts off at 28mm for about 30cm then into a 36mm pipe which disappears under the floorboards. My guess is that thick pipe continues under the ground floor for about 8m then up behind a false wall to the boiler above. If I were to guess the 15mm pipe to the boiler starts there so perhaps about 5m up to the boiler. If I hacked into the wall I would know for sure.

 

[oldbutnotdead]

Well those are good pipe sizes, will wait for @fixitflav and his sums but it isn't what I was anticipating (20m of 15mm), your plumber almost certainly hasn't been naughty, though the 5m of 15mm is a concern.

 

[davecon70]

Well those are good pipe sizes, will wait for @fixitflav and his sums but it isn't what I was anticipating (20m of 15mm), your plumber almost certainly hasn't been naughty, though the 5m of 15mm is a concern.

he literally took the old boiler off and replaced with the new one. Might have to do some keyhole surgery on the fake wall to see what lies behind it!

cheers for the help guys.

 

[oldbutnotdead]

Was the old boiler a combi?

 

[oldbutnotdead]

And interesting, maybe I spoke too soon about the plumber not having been naughty. Just found an online calculator here http://www.gb-gas.co.uk/clc/pipesize/GAS PIPE SIZING 2016 WEB.htm, says it's the 2016 version, also says that 5m of 15mm would cause a (not permitted on installation) drop of 2.28mBar at full boiler load

 

[davecon70]

Was the old boiler a combi?

No. Was an eco tec plus- 2006 model.

 

[CBW]

Do you think it’s worth calling British Gas?

not unless you want it capped off and them trying to sell you a new boiler?

 

[FiremanT]

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