jimi
Well-Known Member
I've just had a holding tank made and I'm thinking it might be a good idea to pressure test it before fitting. What's the best way to do so?
Pressure testing a holding tank
- Thread starter jimi
- Start date
macd
Well-Known Member
I'd be surprised if the manufacturer of what's presumably a bespoke tank hadn't tested it already. You might check with them.
pvb
Well-Known Member
Yes, it's pretty well standard practice to test before despatch.
lw395
Well-Known Member
Fill it with water.
With a hose connected to one port.
Raise the hose so the water level in the hose is however many feet above the tank.
Bear in mind, 33ft or so is one bar, is 15 psi. That is a lot of pounds force trying to distort or remove the lid, if it's a lot of sq inches.
So 1ft of head, 0.5 psi will probably be enough to find any tiny leaks.
Or pump a little bit of air pressure in and wash it with soapy water, lookinf for bubbles.
Air is harder to calibrate, and slow leaks are hard to tell apart from changes in air pressure/temperature.
Maybe do the air test first to find obvious problems?
With a hose connected to one port.
Raise the hose so the water level in the hose is however many feet above the tank.
Bear in mind, 33ft or so is one bar, is 15 psi. That is a lot of pounds force trying to distort or remove the lid, if it's a lot of sq inches.
So 1ft of head, 0.5 psi will probably be enough to find any tiny leaks.
Or pump a little bit of air pressure in and wash it with soapy water, lookinf for bubbles.
Air is harder to calibrate, and slow leaks are hard to tell apart from changes in air pressure/temperature.
Maybe do the air test first to find obvious problems?
pvb
Well-Known Member
Worth remembering that holding tanks are not supposed to work under any pressure, so best not to pump it up very much.
Last edited:
Tranona
Well-Known Member
If it is a Tek Tank then it will definitely have been pressure tested. I watched mine being done when I collected it.
Jabs
Well-Known Member
Don't agree. They can resist little pressure and are not designed to do so.
If the top is, say, 20 by 20 inches, that is 400 sq inches at half a psi that is two hundred pounds force on the top of the tank??
I don't think so!
Tony.
prv
Well-Known Member
I think pvb meant the same as you, but missed out a "not" in the first clause of his sentence. Otherwise the second clause makes no sense.
Pete
Jabs
Well-Known Member
pvb
Well-Known Member
Yes, sorry, missed out "not"! Now edited.
GrahamM376
Well-Known Member
The holding tank in a mate's Bav blocked one time so he blocked the breather pipe and pumped a few too many times, tank cracked and s*** everywhere. Took months for the smell to go:disgust:
jiris
Well-Known Member
Can't resist posting this warning: while pumping the water out (if you have to use pump), make sure the tank is vented and the pump won't be creating vacuum inside. If you omit this, the bloody thing will collapse...
How do I know? I happened to be present when this happened to a gigantic stainless steel tank for heavy water while commissioning the Czech nuclear power station in Temelin
. No, it wasn't funny...BabaYaga
Well-Known Member
An easy way to get a modest air pressure into the tank is to block all openings except one and then put a cut bicycle inner tube over the remaining one (the other end of the cut tube obviously knotted).
I have used this method, together with soapy water, hunting a leak from a fuel tank.
peteK
Well-Known Member
I used an electric dinghy pump to pressurise a fuel tank whilst checking for leaks with soapy water,put a ballon over the fuel filler to seal it and get an idea of the pressure.
Tranona
Well-Known Member
Sounds horrible. Was looking only the other day at the tank in my latest Bavaria and it is rotationally moulded rather than fabricated and nowhere near as robust looking as a Tek Tank, but no doubt cost a fraction of the price of the latter.
jimi
Well-Known Member
Excellent idea!
Aja
Well-Known Member
I would say never assume it has been tested. Ask for a certificate of testing. Should at least give you something to hit them over the head with if the tank ever leaks.
Donald
tillergirl
Well-Known Member
Tek Tank label on my tank shows it was pressure tested to 4 psi
crocks
Well-Known Member
No pressure in holding tank, vent should be 1 1/2” vent to small you get smell , if it hold water it will hold your dinner
Daydream believer
Well-Known Member
I had a blockage at the seacock once so to try & clear it I taped up the vent & pumped the jabsco heads hard. That just made the joker valve blow inside out. However, when I released the deck plug to empty the tank at a pump out station I received a jet of effluent about 4 inches high ( mods won't let me say s..... any more, I am on probation for use of bad language :nonchalance: although I did say it & some other words, which are also banned, at the time).
That is about the most pressure one will attain on the tank in actual use. The pump out station hoses just dip in so vacuum is hardly a problem
That is about the most pressure one will attain on the tank in actual use. The pump out station hoses just dip in so vacuum is hardly a problem
