Pipes too narrow for a combi?

[NickStone]

Thanks for your help, Chris. I'll see how it goes.

 

[Agile]

Although its quite easy to work out the predicted pipe loss with a different gas flow rate I expect only a very few CORGi people will be able to do it.

Chris also mentioned that the pipe sizing can be out by a factor of TWO.

By coincidence thats exactly what another forum regular found yesterday when he checked a newly fitted 42 kW boiler.

I have this idea in my mind that the pressure loss in a pipe may not be linear at high flow rates. Any fluid engineers out there?

Tony

 

[NickStone]

Although its quite easy to work out the predicted pipe loss with a different gas flow rate I expect only a very few CORGi people will be able to do it.

Tony

Thanks, Tony. And probably along with the few people who can do it, there might be also be some who just think they can do it. Someone like me might not be able to detect the difference. I might just decide to play safe.

 

[Agile]

By coincidence I met the proprietor of C & R Plumbing yesterday at the Viessmann boiler company.

He is based in Bath and certainly should know how to do it ! If he doesn't then he will know where to ask!

To be fair he should either be paid to do the test or given the opportunity to quote for the replacement boiler.

Tony

 

[NickStone]

By coincidence I met the proprietor of C & R Plumbing yesterday at the Viessmann boiler company.

He is based in Bath and certainly should know how to do it ! If he doesn't then he will know where to ask.

Tony

Thanks again, Tony . (Er, his website says they're in Leicester )

 

[NickStone]

OK Folks, my plumbing and heating guy came out to look at the property today. He didn't measure any pressures and when I mentioned my concerns to him re the combi he said that the reason BG wouldn't fit one is because their boilers rely on positive pressure. The one he recommended was a Baxi Potterton, which he claims, sucks the gas out through the pipe. This sounded very convincing to me, but of course, I know nothing about gas. What do you experts think? As always, many thanks.

 

[ChrisR]

A nice line of bullsh*t.
We know exactly what he means, and it isn't without a shred of truth.
But the fact remains that if there's more than a 1 mbar drop between the outlet of the meter and the inlet of your appliance when it's running flat out, with everything else, then it's breach of the regulations, and could be dangerous.

Scenario - gas hob on, turned right down to minimum. Then the boiler comes on and the pressure in the pipe drops by a third. Hob goes out. Gas in kitchen. Pong and No dinner.
Gas rises, 5% in air is explosive.
Get cross, decide to go out for takeway so turn light out. Bang goes kitchen.

 

[Dan Robinson]

Nick - that was a complete load of twaddle. Get someone round that knows what he's talking about...


I have had a near identical situation to what Chris describes in the last flat I rented. Mother law was staying over and cooking. I got home from incredibly dusty day at work and had long long shower. Missus came back from shops and notice the smell of gas. I came out of shower to be greeted with much flapping and squarking.

Where mum comes from they do not have gas ovens only hobs - so didn't know what was going on.

The ironic thing was the landlord's new what I did for a living; but still tried to BS me about the whole thing.

 

[NickStone]

Chris and Dan, thanks for replying. You guys are great. I really don't like the idea of gas explosions, so I'm ditching the combi idea for good. This guy was Corgi registered and all- it's so hard to know who to trust. To be fair to him, he did check how many other gas appliances I have (just the hob), but it sounds like that's enough to cause problems.

 

[Agile]

Thanks again, Tony . (Er, his website says they're in Leicester )

Sorry about that, I confused who was from Bath. That was Clive Lowe at C&R !

Its Mike Herrin from Bath. BUT he seems to be invisible on any listing/search medium without resorting to our debt collectors.

I have sent a Private Message to him as thats the only contact method I have for him.

Perhaps you might be able to find him locally? On Monday I could trace him through CORGI.

Tony

 

[gas4you]

OK Folks, my plumbing and heating guy came out to look at the property today. He didn't measure any pressures and when I mentioned my concerns to him re the combi he said that the reason BG wouldn't fit one is because their boilers rely on positive pressure. The one he recommended was a Baxi Potterton, which he claims, sucks the gas out through the pipe. This sounded very convincing to me, but of course, I know nothing about gas. What do you experts think? As always, many thanks.

What a load of carp If the gas isn't there to 'suck' how can it suck it in. The only sucking in being done here is that of you by your proposed installer. Dump him fast. Sums him up if he is proposing a Baxi/Potterton anyway.

All new combis need the same inlet pressure to work, they are all set up to work on a 20mbar inlet pressure, whatever make.

 

[NickStone]

Tony, thanks. That's really kind, but please don't put yourself out any more. You've given me lots of help already. I can contact Corgi myself to enquire about Mike Herrin.

 

[NickStone]

What a load of carp If the gas isn't there to 'suck' how can it suck it in. The only sucking in being done here is that of you by your proposed installer. Dump him fast. Sums him up if he is proposing a Baxi/Potterton anyway.

All new combis need the same inlet pressure to work, they are all set up to work on a 20mbar inlet pressure, whatever make.

Thanks, Dave. Pity, he seemed such a nice bloke.

 

[Dan Robinson]

Not if he was trying to flog you a combi.

Don't dump the idea straight away - if you're in a flat you migth be grateful for the space.

Just get a few people round get them to run thorugh the various aoptions. You alway have this forum to ask questions - we're pretty impartial due to the geographic spread... Although you have to dicern who is a pro and who is a well meaning amateur.

 

[NickStone]

Not if he was trying to flog you a combi.

Don't dump the idea straight away - if you're in a flat you migth be grateful for the space.

Just get a few people round get them to run thorugh the various aoptions. You alway have this forum to ask questions - we're pretty impartial due to the geographic spread... Although you have to dicern who is a pro and who is a well meaning amateur.

Well, I did want the space, Dan, and I wouldn't actually have minded too much if the combi didn't work great. The flat is small, with just the one bathroom so no conflict there. Safety, though, is something else, and everyone seems to think that might be a problem. This guy claimed to be 'Benchmark' and Trustmark'registered as well as Corgi, but I'd never forgive myself if something I'd had installed led to someone else (ie the next owner of my flat) being hurt. I'm going to do what you suggest - get another couple of names from Corgi and ask them to come out. Thanks .