Significant drop in gas pressure between meter and boiler

[donkeeboy]

Hi guys,

I had a Worcester bosch engineer out yesterday to look at my boiler, its been giving me some gip.

Turns out I need to replace CH pump, however during the work guy did a gas pressure test and said it was too low. Now my boiler cover plan from Worcester bosch is invalidated until I get the gas pressure sorted.

It was 13.3 at the boiler - and then 13.1 when the gas hob was going full blast. I have no other gas appliances. I need to have 16.5 at the boiler.

Then I got natrional grid out to test meter, as they changed it abut 6 months ago and I recalled the guy saying pressure was a bit on the low side when he changed it. The pressure at the meter was 21. He adjusted it a bit and said he cranked it up to 22 last night.

I just looked at the pipe work from the mains inlet, to the boiler. There is 0.5 metre 22mm copper coming out meter, then 0.5m 1.25" iron pipe, then 3m 1" iron, then the rest is 12 metres of 22mm copper all the way to boiler. 16 metres pipe work in all.

I counted the elbows, I got 22 elbows between the meter and the boiler. The engineer said yesterday you lose x amount of pressuure per elbow. Cant rememebr the amount, maybe he said up to 0.5 per elbow.

Anyonen got any views? I am losing a lot of pressure somwhere - got no leaks! With that amount of elbows, does it sound about normal to lose that amount of pressure? (22 down to 13.3)

Obv this aint the kind of thing I can sort myself, it's gas, would just like to hear some opinions so I can have some confidence in whats require to sort it out.

Thanks very much guys.

 

[GQuigley67]

why have you got so many tees ? have you got 22 gas appliances ?

 

[donkeeboy]

Oh crap - when I said tee's I meant elbows! LOL Sorry guys!

So 22 elbows - i just have the boiler and gas hob running on gas.

Just updated my OP to say elbow not tee to avoid any confusion

 

[GrahamM]

Firstly it sounds like a very poor install with so many elbows.
Did the Nat grid guy test the working pressure at meter? From your post it sounds like he has just upped the standing pressure by 1 mbar which is not getting you anywhere.
By sound of it you will either need the supply pipe from meter to boiler re-run or have the meter cranked up to a standing pressure of 25 or 26 mbar to give you the gas.

 

[donkeeboy]

Thanks Graham.

Yeah the boiler was installed 3 years ago by corgi guy, the gas pipe from meter is the original one from before, he just changed the bit at end near boiler.

I suspect your right about the nat grid guy. i was not here as he came last night instead of this morn as planned, I guess he just upped the standard pressuure as you say. That extra one mbar aint gonna help your right.

So is this all down to the nuumber of elbows do youu reckon?

Im sure some can be removed but not all that many to be honest, its a tricky run to the boiler in an unusual property.

 

[Bartdude]

When the boiler was installed the gas pipe should have been checked to make sure it was big enough for all your gas appliances.A calculation should be done to determine what size pipe you need. It sounds like that wasn't done which would mean the boiler has never had an adequate gas supply. Bad installation if that's the case but nothing unusual I'm afraid,there are a lot of "boiler swappers" out there.

Find a good Gas Safe engineer to check and uprate your gas supply,it probably needs to 28mm most of the way.

 

[Blackcatgas]

Aye, a nice big juicy length of 28mm and as few bends as possible.

 

[donkeeboy]

OK gents, thanks for your advice.

If there's any gas safe guy's on here in Leicester who wants to do this for me let me know.

 

[Billy Bob Bob]

28mm i have had to go as far as 1 1/4 once many years ago sadly inlet was 20 but the boiler was a Bahama hard to change it for a 105 then when it died LOL

 

[royston]

When the boiler was installed the gas pipe should have been checked to make sure it was big enough for all your gas appliances.A calculation should be done to determine what size pipe you need. It sounds like that wasn't done which would mean the boiler has never had an adequate gas supply. Bad installation if that's the case but nothing unusual I'm afraid,there are a lot of "boiler swappers" out there.


Agree with all of above.


Find a good Gas Safe engineer to check and uprate your gas supply,it probably needs to 28mm most of the way.

And this bit to !

 

[capitanpugwash]

Donkeeboy

You say: "I just looked at the pipe work from the mains inlet, to the boiler. There is 0.5 metre 22mm copper coming out meter, then 0.5m 1.25" iron pipe, then 3m 1" iron, then the rest is 12 metres of 22mm copper all the way to boiler. 16 metres pipe work in all."

If the 3m of 1" AND 0.5M of 1.25" iron are accessible and the rest is quite tricky, I may be inclined to change just the iron pipe initially. Having recommisioned the pipe and tested it, you may find that fixes your problem. It is obviously far better to change the whole lot and straighten out some of your many elbows, but the lead may have been knocked and being so soft could now have a restriction in it along the way somewhere. If it was my house I try this first. Having said that, you may be better of ripping it all out... Good luck

 

[donkeeboy]

Thanks Captain, thats very interesting, as the iron pipes are indeed far more accessible than the rest. I will connsider trying that first, cheers.

 

[Reg Man]

Firstly it sounds like a very poor install with so many elbows.
Did the Nat grid guy test the working pressure at meter? From your post it sounds like he has just upped the standing pressure by 1 mbar which is not getting you anywhere.
By sound of it you will either need the supply pipe from meter to boiler re-run or have the meter cranked up to a standing pressure of 25 or 26 mbar to give you the gas.

You can't crank standing pressure up. Standing pressure and working pressure are totally different things. Done this before on another thread. Standing pressure is controled by a device within a regulator housing, to stop excessive up stream pressure getting into your down stream pipe. Working pressure is controlled by another device within the regulator to control working pressure when gas is flowing through the pipe.

Restriction on this installation, may be caused by debris in the iron pipe. Another thing 16.5mbar at boiler required? If you have 21mbar WP at your meter you are required 20mbar WP on the inlet to your boiler under maximum flow conditions. Some boilers have the inlet test point on the boiler gas valve and additional restriction through the valve can drag the pressure down. If you have an isolation valve with test point at the boiler connection it will give a more accurate reading.

 

[SPC]

I work in Leicester. Give me a call if you want me to come have a look. Steve 07702155576.

 

[yorkieplumber]

Hi Reg Man its happening again lol

You can't crank standing pressure up. Standing pressure and working pressure are totally different things. Done this before on another thread. Standing pressure is controled by a device within a regulator housing, to stop excessive up stream pressure getting into your down stream pipe. Working pressure is controlled by another device within the regulator to control working pressure when gas is flowing through the pipe.

Restriction on this installation, may be caused by debris in the iron pipe. Another thing 16.5mbar at boiler required? If you have 21mbar WP at your meter you are required 20mbar WP on the inlet to your boiler under maximum flow conditions. Some boilers have the inlet test point on the boiler gas valve and additional restriction through the valve can drag the pressure down. If you have an isolation valve with test point at the boiler connection it will give a more accurate reading.