gas appliances

[Dave A]

i will install everything then leave it for a week then call a qualified gas installer and ask him to sign it over...he will tell me what is wrong give me a quote to do the repairs...get what is required and do the changes then call him back.

From what I've seen flowing through my biz on the gas testing side, I recommend against that. I get the sense that it costs more to fix a badly done installation than to put it in properly in the first place.

And yes, I've been staggered at what prices run at for gas installation work compared to electrical work. I expect it's because there are surprisingly few suitably qualified gas installation guys out there prepared to work on domestic gas installations. I know it's been a real scramble for us to find the right guys.

I don't know about how refrigeration stacks up against gas ito standards or hazards, but there is a SANS code that has to be met with gas installations.

When it comes to gas leaks, you don't need to "sniff it out." There's a simple pressure test where you charge the system up to ?* and lock it off for ten minutes. If the pressure doesn't drop - no leaks.

*Can't remember off-hand, but it's not that high. When I get back to work I can check up for you if anyone's interested.

[AndyD]

When it comes to gas leaks, you don't need to "sniff it out." There's a simple pressure test where you charge the system up to ?* and lock it off for ten minutes. If the pressure doesn't drop - no leaks.

This is a standard 'drop test' and it's not an accurate test. With a large installation there could be hundreds of litres of gas in the pipework and even a small pressure drop over a few minutes could mean a very large leak.

With refrigeration a deep vacuum is pulled on the entire system and a similar test is done over time but when using a vacuum a small leak will be detectable far faster than using the pressurisation method. You can't use a vacuum with a gas installation because the pipework wall thickness is insufficient and the pipe will collapse.

Refrigeration engineers are often qualified to work with LPG if they are R600a or R290a certified. Lpg is used as a refrigerant in some domestic fridges nowadays.

[Dave A]

This is a standard 'drop test' and it's not an accurate test. With a large installation there could be hundreds of litres of gas in the pipework and even a small pressure drop over a few minutes could mean a very large leak.

Agreed, although it does perfectly well on the typical domestic installation.

I guess there's a reason why there are different levels of qualification in the gas game too.