gas regulator

[Gyn_Paul]

I'm installing a 23kW instant gas heater, to feed a shower and a couple of wash basins in part of the house which won't be occupied continuously: seemed to make more sense than yet another chauffe-eau heating up and cooling down without being used.

All gone according to plan in that the hole for the flue is cut, and the flexi metal tube goes through the wall and out, and the water connections all fit without leaking (even though I broke my own rule and filled/tested AFTER 10 pm), and the temp gas connection hooked up (off to get the permanent 14mm pipe tomorrow).

However, (sorry Michael Gove) it won't light even with water running through it at full bore. So stop and check everything... retry... no change.

So I'm sitting on the floor idly cradling the gas bottle.... thinking.... and I happened to press the little button on the underside of the regulator and  - wooff ! life! flames! hot water ! just so long as I keep my finger on the button.

So I took the regulator off the bottle, and searched out the fitting instructions on the bedside table and compared the data. Seems the boiler draws .84kg/hr of propane, and the propane regulator's max debit is 1.4kg/hr, so well within its design spec.

Is this just a faulty one?  Is there a butch-er version on the market? I thought the ones with the 1/2" out, as opposed to a nipple were the butch ones.

Oddly, it was working fine feeding a very old ELM Leblanc water heater of much the same size .

Bemused. going to bed. maybe it'll fix itself in the night.

p

[Chancer]

You probably know and understand how they work so this may be wasted but could help others.

The newer safety type regulators have to have sense some back pressure to continue to function, that is to say the restriction of a gas jet rather than an open pipe.

It sounds like your new heater is passing enough gas for the regulator to shut down, you could try throttling the pipe but I have no idea what that might do to the burner itself and it could cause it to emit carbon monoxide so do be carefull, only try it to see if it is indeed the problem.

Could it be a nearly empty bottle perhaps? That would result in a lower pressure at high discharge.

[Gyn_Paul]

Well I fiddled about with the regulator and got no further, then tried it with a 1.4kg Butane one (yes I know the pressure, and so therefore the air mixture, is all wrong) and it worked, so from that I conclude the original propane regulator is faulty: not-so-cheap Italian rubbish.

Next I went to the shopping sheds and bought one of the safety spring-loaded regulators/stop taps which one fixes to the wall. These are plumbed in with copper pipe and have a 15/21 (1/2") male thread on each end.  So to go with it, I bought an extremely expensive no-time-limit 1 metre hose with a 150/20 bottle thread on one end and 15/21 ordinary female on the other.

Imagine my surprise - neigh, joy and delight  - and therefore my bubbling good humour when, at the end of a 120km round trip, I discover that the so-called 150/20 bottle thread only fits the output of a tank regulator (not an anti-clockwise thread). 

Has anyone ever seen a bottle thread to 15/21 hose of a decent length? The only ones I've come across are about 30 cms or so to connect from tall, thin bottles to a change-over thingy. What I need is about a metre long.

And - what is the bottle thread actually called??? anyone know?

p