Use Mains Pressure to Test Vented Hot Water Tank?

[n-hatton]

Might be daft question....

Just done loads of changes to plumbing in property; relocating bath and sink etc. Had drained everything down.

While I can do such stuff, I'm not overly confident. Rather than starting to fill loft storage tanks straight off, wanted to try and pressure test all my solder joints first. Was going to shut valves off to loft tanks and cap off hot water vent in loft, then apply garden hose (which is mains) to the indirect bath and basin pipes to pressure test. Means less water to drain down if if have to redo and solder joint!

Do hot water vented tanks genrally take mains pressure just for this test?


Cheers,
Neil

 

[oilhead]

No

 

[Groovejet]

..no
Take the tank out the equation and test all your pipework.
I use a pressure test pump.

Its a small tank with open top with a pumping handle on it.
You pour water into test pump then pump up to set pressures for certain amount of time. (various instructions on web, for pressures and times etc)

Your basically putting a small amount of water into system under pressure and hold that pressure for a set pre determined time for it to be sound.


If you do it your way with hose pipe, i dont really see the point you might as well use tanks and have means to turn them off quickly if you get problem.

If its a small job, is there any need to use the pump option also???

 

[Blagard]

Tie up the tank ball valve and open the mains stopcock - open cold taps one by one to clear the air and check the cold water pipes for leaks and if good you're halfway there.

Now release the tied up ball valve and start to check to hot water in the same way. If you think its taking to long to check the hot just turn off the mains to stop the tank filling right up. Alternatively, you should be OK to turn off the hot water using the gate valve on the feed to the cylinder but check if it works first!

Edit it just occurred to me the OP might be talking about testing the cylinder not the tank? Even so, no real need to test the cylinder just watch your joints as it fills. Then when the cylinder is full start on the rest of the installation.

 

[n-hatton]

Thanks all. Seems that it's not advisable to have the hot cylinder in line and put mains pressure through it.

I'm not testing cylinder or storage tanks, they are largely unchanged. It's all the indirect cold and hot pipework under floor boards I wanted to test by just using pressure and small amount of water via the hose that I was going to attach to the basin 15mm pipes - bath taps now have service valves that I'd close off. Then just close cold gate valve from loft (which I can still do I assume?) and then hoped for the hot I could shut gate valve from storage tank, but the hot would still be open due to then vent simply open to the loft storage tank. Was planning to push use a push fit cap to seal it for the test.

Mains Pressure would as a consequence pass through the hot cylinder. It was this that I wanted to ensure would take the pressure - sounds like it won't, or at least not advisable.

I'll do as suggested, just let water up to storage tank in small quantities. Wanted to avoid opening pipework to let water out if I do have to redo a joint.

Cheers,Neil