Water test (pressure) new CH pipework

[slimj]

Hi,

I have just fitted new pipe work for a new CH system. The system is all connected back to a combi boiler. I have not fitted the rads yet as I want to decorate etc. first but all the stabbings are in with stop ends on.

I want to pressure test the pipe work before I get the gas engineers to connect the boiler up etc. I have an air kit but I don't want to use this as it is bad practice (and dangerous) as far as I know.

My aim initially was to connect the flow / return at the end and lowest point in the house with a isolation valve and drain off, and then fill the system with the filling loop.

The query I have is that the system will be full of air? Will the boiler have an air admittance valve and even if it does, surely air will remain in other areas of the system. Should I fit AAV to some of the rad stabbings first at the highest point or am I just overthinking it?

Just trying to safely test that is all. Would be happy going for air but it doesn't sound safe given the PSI and I trust what others say on the matter. Would be happy with water as I can see any leaks and now is the time for them.

Cheers all.

slimj

 

[Agile]

Since most leaks will be at connections to rads, I don't seem much point in any testing until they are fitted.

Tony

 

[slimj]

Cheers Tony and I agree.

Issue is that I am waiting to finish putting new floors down (glued and screwed) and getting plasterers in.

If I know the pipework under the floor's are all sound I will feel more confident getting work finished and then just test each rad as a fit. Drain, fit, fill etc.

Anyway I can test the pipes at this stage?

 

[Agile]

Why do people like to do work in the wrong order?

Boiler and pipework completed.

Plasterers do walls.

LAST, fancy floor is laid.


Your lovely new floor is likely to be spoilt by mess from plasterers. Plastering is a messy business.

 

[slimj]

Mainly because the plasterers would struggle to plaster ceilings balancing on a load of new I joists. Yes I could board 4 rooms temporarily but that also feels more like the wrong order and more time/expense. I have no issues following around scraping up some plaster. The stage I am at wrong order or not is trying to test the pipework so I can lay the last of the floor.

 

[MJGas]

Why do people like to do work in the wrong order?

Boiler and pipework completed.

Plasterers do walls.

LAST, fancy floor is laid.


Your lovely new floor is likely to be spoilt by mess from plasterers. Plastering is a messy business.

Fancy floor? Sounds like he's just screwing and gluing chipboard down.

 

[oldbuffer]

Why not:

1. Replace stop ends on flow and return to highest radiator with manual air bleed valves.
2. Connect mains as you suggest but buy and fit a pressure gauge as well unless you can use the one in the boiler.
3. Make sure you don't let the pressure go over (say) 2.5bar, or you risk operating the pressure release valve in the boiler, which may not re-seat.
4. Check pressure after 15 minutes, return to 2.5 bar if necessary.
5. Make sure pressure holds at 2.5 bar for 1 hour.

If you want to do it properly:

a. Hire a pressure pump (e.g. Rothenberger RP50)
b. Take the boiler out of the circuit as you don't want excess pressure in it. Disconnect flow and return and temporarily join them.
c. Take anything else that can't take more than 4.5 bar out of the circuit
c. Fill system with water using the mains (unless you fancy doing a LOT of pumping)
d. Pressurise to 4.5 bar (1 1/2 times maximum operating pressure on a combi)
e. Check pressure after 15 minutes and re-pressurise to 4.5 bar if necessary.
f. Make sure pressure holds at 4.5 bar for 1 hour.
g. Drain, disconnect pressure pump, re-connect boiler.

 

[slimj]

Fancy floor? Sounds like he's just screwing and gluing chipboard down.

I am! I thought that was obvious. I don't know anyone who would lay a new floor covering and then get plasterers in but NVM.

Why not:

1. Replace stop ends on flow and return to highest radiator with manual air bleed valves.
2. Connect mains as you suggest but buy and fit a pressure gauge as well unless you can use the one in the boiler.
3. Make sure you don't let the pressure go over (say) 2.5bar, or you risk operating the pressure release valve in the boiler, which may not re-seat.
4. Check pressure after 15 minutes, return to 2.5 bar if necessary.
5. Make sure pressure holds at 2.5 bar for 1 hour.

If you want to do it properly:

a. Hire a pressure pump (e.g. Rothenberger RP50)
b. Take the boiler out of the circuit as you don't want excess pressure in it. Disconnect flow and return and temporarily join them.
c. Take anything else that can't take more than 4.5 bar out of the circuit
c. Fill system with water using the mains (unless you fancy doing a LOT of pumping)
d. Pressurise to 4.5 bar (1 1/2 times maximum operating pressure on a combi)
e. Check pressure after 15 minutes and re-pressurise to 4.5 bar if necessary.
f. Make sure pressure holds at 4.5 bar for 1 hour.
g. Drain, disconnect pressure pump, re-connect boiler.

Thanks oldbuffer, really appreciate your time. It was the bleed valve part I wasn't sure on. I would follow the proper method but it took some time getting the flow and return all fitted so I am happy with them, so i will go for the 2.5 bar method 1. If that holds for an hour I should be all good