Propane regulator needle won't zero

The regulator pictured was bought new last year and has only been used a handful of times. It is for use on disposable Bernzomatic style gas bottles.

The problem is that the needle won't return to zero, and wildly erratic readings now result when it is used.

Does anyone know whether there is a cure for this sort of problem, and if so what?

Thanks.

Dis-assemble gauge and repair if possible or get a new gauge.

The most common cause is simply the needle fouling the dial or the glass, easily fixed if the bezel will come off.

The thin-walled bezel is welded to the body of the gauge, hence, if disassembly takes place, re-assembly won't, at least not with the same bezel and body. The lens is plastic.

Posted by Paul Lousick on 05/01/2023 23:57:01:

I or get a new gauge.

They're no longer available from the supplier I bought it from nor from any other supplier in the UK I'm aware of.

The needle isn't fouling anything visible to me.

Unscrew from regulator body and check thread May be 1/8" gas/bsp or 1/4" replace with 0-50psi gauge redilly available in many places. Noel.

Maybe a bit of FOD has got into the gauge, which is preventing it returning to zero?

I notice it says not to oil it, but could you remove the gauge and alternately apply pressure and vacuum to try to dislodge whatever is causing the jam? Something like a large plastic syringe might do it, with the appropriate tubing and adaptors..

Noel, I've unscrewed the gauge from the regulator. The thread appears to be M9x1.0 - definitely not BSP 1/8" or 1/4" at any rate.

Is there a suitably threaded gauge to fit that out there?

John, I'll have a go at blowing and sucking now that the two parts are separated.

Thanks to all so far.

Overcoming my initial pessimism, I've done some slow but determined prying and managed to get the bezel and lens off. I'll disassemble the guts of the gauge when I next have an hour or two spare. At the moment, if I return the needle to zero with my finger it just springs back to its original position at around 0.5 bar.

Maybe (Likely?) NPT - 27tpi?

What pressure are those Bernzomatic bottles at ? Quick search on the net says 228psi. Is the gauge on the bottle side or delivery side. If the gauge has been over pressured, then the Bowden tube may have been deformed.

easily done !!

If the Bourdon tube is still intact you will need to pull the needle off the spindle and replace it to zero. I still have a Budenburg pointer lifter lying about the workshop from my Tiffying days.

If you reset the pointer to zero how are you going to know whether the gauge is reading the pressure accurately without checking the range on a deadweight tester, I wouldn’t trust the gauge without being able to verify that it is reading accurately. Dave W

That's bad news. My limited experience is broken gauges of the basic kind are hard to fix. They're not designed with maintenance in mind, so anything other than a simple problem like the needle fouling the glass, is likely to be difficult to fix. You certainly don't want to do anything that might cause it to leak gas. Worth looking inside, but I fear it will have to be replaced.

Shouldn't be difficult once the thread is identified, unless the existing gauge is a weird shape. It looks ordinary though.

Dave

Just not worth tinkering with. Replacement gauges are cheap and plentiful. I am sure making an adapter would be simple enough for a model engineer.

Andrew

Hi, not what you want to here, but faulty regulators, whether it's the gauges or the regulators no matter how old they are, should be replaced, and if it has gone wrong within in the first year through no fault of your own, the supplier should replace it under guarantee. All portable gas regulators etc. have a life of five years, whether that's in use or sitting on a shelf in a box.

Regards Nick.

Just to round this thread off, I got the needle and the dial plate off, and found a spring inside had become displaced from a toothed half-wheel. After a few trial efforts I worked out where the spring was supposed to sit to get the needle resting comfortably back at zero.

I've been using the regulator without problems for a few weeks now, and I'm confident it's reading the way it was designed to. It gives very stable readings and there is certainly no evidence of any leakage in the system anywhere.

I'm not saying this is a permanent fix, nor advising anyone to follow suit if they encounter a similar problem with their own regulator, but given the way my regulator is now behaving and the fact that it has never been over-pressurized I don't think its safety is necessarily any more compromised now than it was as a result of the way it was originally assembled in the factory.

My motivation for saving it was, as I've already said, the fact that this kind of regulator is no longer for sale anywhere in the UK; if someone one knows differently, I'd be pleased to know where.

I would just point out that the gauge pictured would not have been allowed to be used for pressure testing or on gas equipment where I worked. You were not allowed to use gauges with a hard stop at zero as you could not tell if the gauge was reading zero when depressurised, it may still have pressure in it even when reading zero. Also the hard stop could knock the pointer needle around on its spindle resulting in inaccurate readings. If you get a replacement aim to avoid such gauges for something used with flammable gasses.

Martin C

Thanks for the advice, Martin [and to everyone else who's contributed].

It's proved difficult finding a replacement gauge as the thread on mine is M9x1.0.

If anyone knows where I can get one I'll certainly follow that up.

could you make an adaptor