Acceptable gas pressure drop between meter and boiler?

He's maybe one of them!!

 

I'm no millionaire ... but most of my work comes from the Sandbanks and Canford Cliffs areas.

It is great fun installing lavish state of the art bathrooms and kitchens ( mainly bathrooms) and I do enjoy meeting some of the er... "characters"

 

Bet it's costly if you break any of this posh stuff by accident!! LOL

Not so bad with screwfix or standard stuff.

Expensive stuff though different ball game.

That's why people charge that bit more fitting it.

responsibility of the breakages...

LOL

 

Spot on, even tiles ( 1M square beasties recently!) can cost a packet - I usually get the customers to pay for the materials on delivery.

 

..but I still do ordinary jobs for existing customers and smaller bathrooms which come my way - it's all work isn't it.

 

Gordon, no a 3mb drop will not be acceptable to the manufacturer. Any fault that develops on your boiler will be blamed on a poor installation. It says in the commissioning section of the book for your boiler to check for 20mb and if it is not achieved not to proceed until corrected.

The book for the 37cdi even points out that 22mm will be insufficient for providing the correct amount of gas to a boiler that size.

 

Standard practice is no more than a 1mbar loss on the whole installation no matter how many appliances are connected.

 

Smithp60 you beat me to it , I have just read though this lot , You are confusing pressure drop with tightness test , on a tightness test you are not allowed any drop as it`s a new supply even with appliances connected , You are allowed a 2mbr pressure drop(used to be 1 ) from the meter to the boiler/hob/fire , then you have your working pressure at the boiler as stated of 18mbr .
If it`s 17mbr get the fitter back and moan .

regards
chris

 

chris73
when did it change to 2 mbar loss?

 

Hi Gordon.

I suspect it's as you suspect - after re-doing the pipe feed, the Corgi was too embarrassed to admit he's under-spec'd it.

If there is a 3mb drop over this length with no other appliances running, then that's pretty significant. I'm surprised a test wasn't carried out with your hob running full on, tho'?

Also, the guy has left a feed for the - currently - disconnected gas fire. Clearly, by leaving this connection, he's implying that the fire could be used in the future - another shared load (although, as it's very close to the meter, and fed from the 28mm pipe, it probably won't have that much of an effect.

10m is a fair length, tho' not unusual. 11 bends is quite a lot tho'!

I guess your options are to (a) tactfully contact the original Corgi and insist he sorts it - almost certainly 28mm all the way, or (b) get a different guy to do it...

However, you cannot get a new guy to fix it and expect the original one to pay UNLESS he refuses to accept responsibility for the mis-calc. In which case you inform him of your intentions - he will be billed for the job and reported to Trading Standards (being tactful all the way, of course...)

Remember, you just want it sorted, with as little grief as possible. If you go in all bolshy, he'll get the hump. He'll still have to come out, of course, but do you really want a tetchy, grumpy Corgi in your house?

 

Gordon,Are the worcester engineers figures with other appliances running you don"t say.The gas supply run you describe definately wants upgrading to 28mm as near to the boiler as possible,also replace elbows with pulled bends where possible.

 

Just to clarify; The Appliance Inspection Report
states:

Working Pressure at Boiler 17mb (18-21mb)
Working Pressure at Meter 20mb (20-21mb)
Installer to investigate.
Appliance has been left turned off and warning label
fixed.

Were you having problems with the boiler? cos although it's slightly undergassed it's nothing compared to a lot that you see. I would have said that as long as it was gasrated and found to be burning the correct amount of gas it would have been fine. As da said though the only option to get it spot on is to upsize the pipework. Before doing that though it would be worth having a pressure test tee installed just before the boiler, and seeing what the pressure drop in the actual pipework is.

 

I am really trying to get a steer on whether what has been done is legal, good practice and whether it is reasonable of me to expect the installers to address it.

Seeing as it's a new installation, and it's been turned off and labelled, then of course it would be reasonable of you to ask the installer to address it. Good practise is a maximum 1 mb drop in the pipework as said, although it more often than not is more than that.

 

There is a lot of hot air on this thread. Firstly, the pipe sizes must be calculated. The 42CD! consumes 4.4 cu Metres gas per hour. Look at the tables in the link. 9 meters of straight 22mm pipe gives 4.6 cu m/hr. I think there is more than 10 meters of pipe when it is all measured, back to the wall from meter etc is never taken into account. It looks like borderline case.

http://www.cda.org.uk/megab2/build/pub124/sec3.htm

The link above tell you how to size up the supply.

Points;

* A 28mm meter outlet connector should be used. Many keep the existing 22mm connector and connect the 28mm pipe to this. Must 28mm right to meter union.

From http://www.bes.co.uk
Part No. 0246 plus a new washer.

* The gas fire rightly is teed off the 28mm pipe at the

* The hob requires its own gas supply right back to the meter outlet teed into the 28mm pipe. The boiler requires its own <u>dedicated</u> gas supply. In theory if the pipes are sized properly you can tee off the hob at the boiler. In practice surge at switch on can cause problems, especialy with a boioer with a high gas rate.

1. I would get them to make sure a 28mm meter connector is at the meter outlet.
2. Take the hobs gas supply right back to the meter.
3. Get them to put 28mm right through the roof void. One three metre length may do it

If problems after all this see National Grid, as it may be an undersized maintap with a 3/4" flexible inlet. Sometimes if the flexible inlet is bent too tight, very common, restrictions in supply can occur.

 

I would have said
that as long as it was gasrated and found to be
burning the correct amount of gas it would have been
fine.

Until he turns the hob on!!!!

Read my post on how to do it.

 

Gordon, how is the boiler operating in general? What is the DHW flow rate like? How fast to fill a bath, etc? Is it noisy?