Pipes too narrow for a combi?

[Dan Robinson]

Nohing beats recommendations. Names you get from CORGI are merely a directory service - not a sign of quality.

Benchmark registered

thats a good one

 

[gas4you]

Try to work out approx the route the gas pipe would take, tell us the length and add 0.5m for each anticipated bend and also tell the pipe size off your meter and also if any other gas appliances are being used in your flat. We could do some average calculations for you.

 

[NickStone]

Try to work out approx the route the gas pipe would take, tell us the length and add 0.5m for each anticipated bend and also tell the pipe size off your meter and also if any other gas appliances are being used in your flat. We could do some average calculations for you.

Thanks, Dave. That is so kind. I've had to measure the pipe with a steel rule because I don't have calipers but the diameter at meter seems to be 22mm. At my boiler, it's 14mm, but the change happens somewhere under my floor so I'm not sure exactly how long each bit is. Worse case scenario, allowing for bends, is 23.5m of 22mm plus 11.5m of 14mm. Best case scenario would be 31.5m of 22mm plus 3.5 of 14mm. I have 5 rads plus a bathroom towel rad. The only other gas appliance is a hob. (Just writing this down, I can practically see your head shaking a negative. Well, it's best I know. Many, many thanks.

 

[Dan Robinson]

How many bends?

Over compensate if you can...

 

[NickStone]

How many bends?

Over compensate if you can...

About eight, altogether and I have added .5 of a metre for each, as Dave said.

 

[gas4you]

Unfortunately doesn't bode good for a combi

Worst case scenario you posted would be about 12m of the 23.5m of 22mm being changed to 35mm, then 28mm up to about 9m from the boiler. The rest in 22mm up to gas tail on boiler. This is based on a 31Kw boiler using 3.3m3/hr. Larger boiler would be worse

 

[NickStone]

Unfortunately doesn't bode good for a combi

Thanks, Dave. Really appreciate your input. Pity you're in Norfolk and not in Somerset .

 

[Dan Robinson]

We might be getting some 22kW combi's coming to market soon, but even then I think you are going to have trouble.

There are some very small high recovery cylinder available..

 

[NickStone]

We might be getting some 22kW combi's coming to market soon, but even then I think you are going to have trouble.

Yes, I think I'll play it safe and just get an ordinary one. I realised yesterday, too, that my mixer shower might not be right for the combi either. Many thanks for your help.

 

[gas4you]

Still needs to be worked out correctly though, a 12 Kw heat only boiler will use around 1.2m3/hr gas, so sounds a lot more probable that it will be ok.

If you still had minor problems with the pressure drop across the pipe work, your installer could call NG out with a pressure problem and ask them to set it to the maximum working pressure allowed. Although this would still not technically meet regs it would probably give a safe inlet pressure for the appliances to work on.

 

[NickStone]

I guess one option would be simply to leave the old boiler alone until it finally breaks. It's an Ideal Concord WRS and as far as I can tell has never been serviced because the cover can't be removed (because of its position on the wall.) (Scrub, that, I just got the cover off and boy is this thing corroded, full of rust and all.) In future, I think I'll steer clear of flats. At least with houses, you can have new pipes routed in without all this bother. Thanks to you guys on the forum, I now know a lot more about boilers than I ever thought necessary and all I can say is, I admire all your skills.

 

[gas4you]

Is there any way that a new gas pipe could be run externally up to your flat? What would happen if a leak developed in your existing pipe work?

 

[NickStone]

Is there any way that a new gas pipe could be run externally up to your flat? What would happen if a leak developed in your existing pipe work?

Unfortunately, it's a listed building and permission would never be granted. British Gas were going to run a new wider pipe inside my flat to replace the really narrow one. I think that might be my best option.

 

[Agile]

Unfortunately, it's a listed building and permission would never be granted. British Gas were going to run a new wider pipe inside my flat to replace the really narrow one. I think that might be my best option.

BG dont have any monopoly on installing gas pipes. Any CORGI can do that ( usually cheaper ).

You need a competent CORGI to assess the existing gas supply and advise what improvements can be gained by upsizing pipes where possible.

This is a problem we deal with all the time.

Mike lives in Wimsley if that helps.

Tony

 

[NickStone]

Thanks, Tony. Good advice. I'll ring around tomorrow. Winsley(?) is out near Bradford on Avon so it's a definite possibility. I tell you, I am so grateful to all you guys for taking the time to help me out with this. I'll let you know how I get on.