Gas pipe to combi boiler.

Can't see why, just need to use end feed,solder ring, imperial/metric Adaptor 22mm x ¾", the 3/4" copper pipe is about 1.4mm less than 22mm.
But, using a 22mm fitting on an old 3/4" gas pipe and filling the gap with solder,you are contravening the gas safety regs.

 

I thought you could use a copper to iron compression fitting 3/4 to 22mm, sorted??? Any plumbers on here care to comment.....

 

We need Dave to clarifiy that one.

 

He does not say if the pipe is iron or copper,but the way it is written it sounds like copper.

 

That's what I also think.

 

It would fit but no compression fittings allowed on gas if under floor boards.

 

Close but it is allowed if its accessible. The regs state no compression in an un accessable position.

OP 3/4" is acceptable to supply a combi (Dependant upon length ETC). Can I suggest you leave it all in the hands of your registered installer. Have a word with him if needs be he can alter the pipework before fitting the new boiler so you can get on with your bits.

 

Sorry to hijack post, but I'm curious about the comment;

"using a 22mm fitting on an old 3/4" gas pipe and filling the gap with solder,you are contravening the gas safety regs."

Is it the fitting/soldering of it in situ that is against the regs? Would that be acceptable it the soldering was done on pipe that wasn't connected, (i.e. didn't have gas in it!), and the soldered pipe was connected to gas afterwards?

I repeat, not something I'm planning on doing, just curious!

Thanks,

Cando

 

Lennie, what size (kW) combi are you having fitted? And is there anything else fed by this gas line?

If it's a big combi - ooh, 38kW+ - then 3/4" pipe over 7m might be borderline, at least if there's some bends in it.

If it's a normal combi ~30kW - then you should be ok.

But really a GasSafe cove on site should determine this.

 

If the pipe to the cooker comkes off the 'main' pipe close to the meter - and not close to the boiler - and if the cooker ain't a huge 'burner', you will probably be ok.

But, I for one certainly can't tell from here.

Combi boilers are designed to heat yer DHW instantly, so for this it'll run flat-out. In your case that means 28kW. Any idea what your old boiler's rating was?

There are calcs involved. Not complex, but they do consider the overall length of pipe, the number of bends (3 ain't many), the kW of the boiler - and the kW of any other appliance sharing the same pipe.

Do you have a GasSafe cove in mind for the boiler install? If so (and you should...), then give him a call and ask him about this.

 

Once again Im going to state the obvious, Lenniegee, you have yourself a registered installer yes? Then get hiom in before you start other work and let him do any prep work that is required. It aint rocket science, let the guy on site do his thing and ignore advice given on here by unqualified people. Thats why your paying him for his expertise and experience.

 

Very interesting.
I have just last week had a Potterton Flamingo 50 and an Elson Tank removed.
It had run for 35 years.Yes 35. Only repairs 4 thormo couple sensors.

I had it replaced with an Intergas 36/30. With RF room control fitted.
22mm was extended as the Potterton was supplied with 15mm
All existing radiators 8 taken off the wall and flushed out with the garden hose.
All new valves fitted.
A radiator changed for a new bigger one.
And an extra radiator added.
The cleaning agents were added with the big Magnet kit temporarily fitted and
ran for 10 hours.
Then an ADEY magnetic filter permanently fitted.
The boiler removed and the elson tank and an extra tank removed .
And basically all tidied up.
Cost £3000 as near as damn it.
I was quite satisfied with the price.
And they got a full dinner supplied all 3 days. Fish & Chips/Sandwich/Pizzas
It seems that does not happen often lol.

In testing I am very pleased with it.
The 30kw does the CH very fast as against the 19kw Potterton.
Now my experience with DHW for the bath.
I am so pleased I fitted the 36Kw I think less Kw could be disappointing.
In terms of getting the bath filled and hot quickly.
Just my thoughts for what its worth.
I was a plumber foe 15 years 50/60s its all changed somewhat lol.

I would say to Lenniegee get the bigger DHW one.
Just my thoughts.

 

What about hot water requirement for kitchen.

And as to boiler, Valliant.

 

Lennie.

If you are happy with a 28kW combi - and it should be fine for most purposes - then a 3/4" pipe over that length should be ok too. (You can't see, but I've licked my index finger and held it up in the air to calculate that.)

But, you do also have another draw on that same pipe, and the supply must be able to handle both without a significant drop of pressure at either appliance - cooker or boiler.

I totally understand you wanting to crack on with your renovation and get that new floor down. But I fear it may be a gamble.

What would you do if the GasSafe does the calcs and says he ain't happy with 3/4" - he says 22mm is fine but anything even marginally narrower is borderline? And he adds that he won't know for certain until after installation and he runs both appliances at full chat to test? And there's a chance your floor may need to come up?

And you get another GS in for a quote and he says "Hmmm...ummm...welll... och, it'll be fine. I'm pretty sure..."

Really worth all this for the sake of choosing your GS now and asking him to pop in for 5 minutes for a looksee?

You currently have a leccy shower? And that's going to remain that way, is it? Shame, because combi boilers - even 28kW - will give a superb shower.

And for your kitchen sink you are going to boils kettles for your hot water? (Checks calendar - nope, it ain't 1916...)

 

Bad idea I say, if you every decide to sell, you'll put off buyers with no hot water to taps.
You really need to sort out size of pipe first.