which pressure tester should i buy? wet or dry?

[long-pass]

Hi everyone, i am looking to finally buy a pressure tester but cant decide on which sort. i have been using my mates rothenberger rp50 which is good but a bit bulky and its on the expensive side for something i might use a few times a year. should i buy a dry test kit? would i need to buy an air compressor then? i doubt i will use it for more than 8 rad systems but if i buy the smaller rothenberger rp30 will i be pumping it all day? i have never used a dry tester, are there any advantages apart from if there somehow is a leak (which has never happened to me before :uhoh2: ) and only air comes out? any advice would be much appreciated.

Cheers in advance

 

[mountainman]

I've used both types and my personal preference is for an air test. I use a car type tyre compressor to pump up or else a foot pump.

You can make your own kit up for not much money

 

[Roger Welton]

With a air test there is much more energy stored in the pipework as it is compressible, so if a fitting lets go you know about it! It is easier to rig though and if you have a leak not such a pain to 'drain' to remedy.

 

[AWheating]

safer to do a water test, the large rothenberger pump is the best one you can have, the smaller ones take alot longer to use and break alot quicker then there bigger brother.

 

[dontknowitall]

I use a vertical bicycle pump and a Monument dry tester. Cheap, simple and effective.

 

[long-pass]

Thanks for the advice everyone. I am probably gonna go for a dry test kit and use my foot pump. got a plumbfix voucher lying around so might as well use it as they do the rothenberger dry test kit.

 

[cr0ft]

Not sure I would want to be doing dry pressure testing above 1 bar on any pipework with plastic fittings on. As has been said, if a fitting fails expect it to fly off as if it was fired from a gun. For testing to 10 bar which is what Speedfit ask you to do on each install, wet testing is the way to go. As for the RP30, I have one. Takes quite a bit of pumping to get it up to 3 bar or so, then the pressure increases quite quickly. I wouldn't be without it, it allows me to sleep at night and avoids that Friday afternoon syndrome when you've finished and are filling up a large heating system.

 

[dancinplumba]

why not use pressure washer with pressure reducing valve, isolator and pressure gauge instead of a lance ???

 

[long-pass]

Did not even think of that cr0ft so cheers mate. i have stopped using speedfit and have started to use the newish hep20 stuff, which has to be tested upto 18bar! the dry test kit only goes to 4bar as well. decisions decisions

 

[Mike Jackson]

Both is the best bet. Initial low pressure test with air to prevent damage followed by high pressure test with water.

 

[hammers4spanner]

I use me apprentice to blow down hosepipe linked to a DOC with a jubilee ,,,,it doesnt work and is rubbish but its funny watching him go bright red with huff and puff!!

 

[steveafoss]

Both is the best bet. Initial low pressure test with air to prevent damage followed by high pressure test with water.

I do the same for a full install 1 bar air pressure test leave on for 1 hr while doing other stuff, if ok test with water 3 bar.

Steve

 

[MattWeth]

Good thread.

Just starting out on my own, the big Rothenberger wet test machine is stretching it but I'm going to get hold of the RP30 to supplement my air tester.

Edit: although I've just found the RP-50 at half the screwfix price so perhaps not as bad as I thought...

 

[MattWeth]

Did not even think of that cr0ft so cheers mate. i have stopped using speedfit and have started to use the newish hep20 stuff, which has to be tested upto 18bar! the dry test kit only goes to 4bar as well. decisions decisions

18bar?!
I've not seen the hep20 specification but are you sure you're not confusing the rated maximum working pressure of the fitting with test pressure? I wouldn't be pumping up a domestic water system to 18bar - I'd test at the regulation 1.5 times the operating pressure. I'd have thought at 18bar you'd get all sorts of interesting explosions on a domestic system...

 

[cr0ft]

Speedfit specify 10 bar but in reality if you've ever tried testing a domestic heating system to 10 bar you will hear the radiators starting to creak at 9 bars - most radiators are only pressure tested to 10 bars at the factory. I've never tested one to 10 bars for this reason, I figure if the fittings can stay on at 9 bar then there probably isn't anything wrong with them! It goes without saying that 18 bars is a hell of a lot of pressure and I wouldn't expect a radiator to stand up to that sort of pressure to be honest. If that figure is true then the engineers at Hep2O don't have a clue.

 

[cr0ft]

@dancinplumba, that has got to be a wind-up right, the pressure washer idea?

 

[long-pass]

The hep20 testing guidance states that you test the fittings which have grab wedges to 1.5 times the working pressure and the fittings with a grab ring and the slimline fittings to 18bar for 1 hour. obviously disconnecting anything which cant take that pressure i.e everything else. i may have to go back to speedfit. or get an apprentice with a bulletproof vest for the blowouts