d-i-y boiler test

Certainly it should be hydraulic (ie water) tested and not air tested, for safety reasons. A burst with water releases the pressure rapidly as a small volume escapes, however air would potentially be a bomb. Fill with water, arrange a small hand feed pump to pressurise and have a good quality gauge attached.

Google will show the way!

AWEM

Thanks Andrew, I've googled but I can't find any detail of the type of pump used for the job, that's why I was asking here. I have a 1/2" bore manual feed pump but I was assuming that something more substantial would be required to achieve the testing pressure.

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bomb.

Normal boiler feed pump should be ok, after all it has to overcome steam pressure in use by some sensible margin.

AWEM

Several of the traction engine guys use a plumbing testing kit you can get them from machine Mart

And as said don't test it on air.

Jason

There's a combined pump and reservoir available in the Screwfix catalogue - that's exactly the same as my boiler inspector uses for the job.

1.5 times normal working pressure is the standard required. That said, if you're in doubt about the boiler I wouldn't chance steaming it right up to WP without a thorough examination, you really need to borrow a thickness tester to do the job, combined with the Mk 1 eyeball.

It is possible to improvise a pressure source using a standard pressure washer, you take the output and feed it through a variable valve. Take a 'T' off it before the valve and connect to the boiler. These pressure washers work at about 1000psi or so, so great care is required, if you subject the boiler to pressure of that magnitude you'll distort the thing for good!

Julian.

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....argh .... NO .... don't go anywhere near it with a Pressure Washer ... orders of magnitude too high a pressure. Manual feed pump will do the job quite adequately.

AWEM

There are some complex laws about that, but I don't know what they say. Local club is prolly the answer, I don't think you still have to put on aprons and do funny walks with a bun strapped on your knee these days.

I've used a grease gun sometimes for pressure testing, but that only goes up to 10,000 psi. :(

-- Peter

Plenty of people do, I've been involved with steam for a decade. Re-read my post carefully, you 'T' off a supply to the boiler before a tap or valve that dumps the output from the PW. - you slowly restrict the flow from this valve until you get the pressure that you need and no more (this is the bit that I suspect has gone over your head?) - use common sense, a good 'ear' for the job and it'll do very nicely - and probably doable for next to nothing.

Julian.

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Well I hope you're not a future Darwin award winner - totally unnecessary risk When something blocks your valve the whole neighbourhood will hear your demise.

This a a small model boiler. The o/p needs a very low volume pump that will generate perhaps 200 psi max under easily controlled conditions. The manual boiler feed pump fulfills those requirements nicely. If reguarly testing model boilers then a hand pump of the type used for pre-commissioning c/h plumbing is handy:

But for a one off then use the feed pump!

AWEM

Oh for gawd's sake take a reality pill, WTF is going to block the valve. I suppose Severn Trent Water are standing by to introduce a tanker full of ''Bars Leaks'' into the mains when they read this thread. And as for anyone's demise - perhaps you could revisit the purpose of using a liquid, rather than air, for test purposes and refrain from hyperbole.

Yes, we all know that, it's not a rocket science project here, my suggestion is a way of saving £120 for something that'll get used probably once.

Julian.

Thanks all for the ideas, I'll try with the manual feed pump, I only need 90psi (1.5 x working pressure of 60psi). Another question if I may: obviously I will remove and blank off the safety valve, what about the sight glass? Should I remove it and use blanking plugs, or should I also test that the sight glass itself is good for 1.5 times working pressure?

Test it with the sight glass in place. It'll stand the pressure with no problems at all.

regards

Mark Rand RTFM

--A half inch bore manual feedpump is *huge*! Be careful when using it on a boiler (properly) filled with water: that gauge needle will move very quickly and you don't want to damage the gauge itself.

Despite what others have said about air testing, it is possible to do safely. The danger with air is that it's like a spring with a huge amount of stored energy. If the boiler fails, it can explode. Fill i he boiler completely with water and then only use the air line to presurise it. 90psi should be achievable with a normal air compressor.

John