Should I pressure test relatively small plumbing job

[smallsteve]

I am a DIYer that is looking to address piping under my en-suite floor, whilst I am undertaking a major re-ferb of the room.
With reference to the picture, you can see that I have a number of JG connections under the floor and they will ultimately be tiled over. To complicate things further, access from below will be difficult as they are directly over a brick wall. You can get to the area, just, by cutting into the ceiling and removing coving; might work, but also might not!
I have the option of simply replacing the (20-year old) connectors on a like-for-like basis, or switching to copper and replacing the 22mm feed and return, plus all connectors. Opinions?
My main question though relates to whether i really ought to acquire a pressure tester and test the finished job, or whether it’s a tad overkill in this instance? I guess one option would be to simply rely on typical system pressure from the combi and keep my eye on it for a period of time? I watched a video on YT earlier of a well-known plumber and that’s what he did, which surprised me a bit. I get that this is a subjective question by the way!
Other things that i’m not 100% on are firstly that i read that JG recommend isolating rads, sanitaries and boilers when testing the pipework, but surely rads and tap connections also need to be checked for soundness? If i exclude the rads then i am only testing a couple of pieces of pipe and a few fittings! Finally, i note that plastic pipe should be tested with varying load for a period of time and a basic tester (e.g. RP30), is not going to be capable of that. Am i therefore wasting my time even considering this?
in a nutshell, i want to do the job properly, but not make unnecessary work for myself. I consider myself to be a competent DIYer and have all plumbing tool ar my disposal, bar the pressure tester.
TIA and apologies for the rambling post.

 

[steadyon]

1. There are two reasons for pressure testing with plastic pipe:
1a. To ensure there are no leaks (same as for copper).
1b. To make sure the grip rings which hold the pipes into the fittings have "bitten" into the pipes correctly.
2. The recommended pressures for testing (plastic) vary by manufacturer. However, 10 bar for 30 to 60 minutes is common. A 10 bar pressure is enough to permanently damage other fittings, like taps, boilers, valves etc. This is the reason such other items should be isolated. You are quite right, this does not permit the whole system to be tested, but does normally allow all items which will become inaccessible to be tested while it is still (relatively) easy to put things right.
3. I personally try and avoid plastic pipe, and prefer soldered copper. Whenever possible I still test to 1.5 times working pressure (which for a combi based system I take as 5 bar) for at least 30 minutes. 5 bar is the maximum working pressure of most plumbing items.
4. I can't see why a Rothenberger RP30 can't be used for the tests you envisage. It will go well beyond 10 bar. The RP50 is perhaps easier to use, and you could probably hire one.

 

[Ben-gee]

How many times are we going around these houses?
Eventually you have to stop asking and actually do it!
As numerous other threads , you’ve been advised to switch to copper in this area.....

 

[smallsteve]

1. There are two reasons for pressure testing with plastic pipe:
1a. To ensure there are no leaks (same as for copper).
1b. To make sure the grip rings which hold the pipes into the fittings have "bitten" into the pipes correctly.
2. The recommended pressures for testing (plastic) vary by manufacturer. However, 10 bar for 30 to 60 minutes is common. A 10 bar pressure is enough to permanently damage other fittings, like taps, boilers, valves etc. This is the reason such other items should be isolated. You are quite right, this does not permit the whole system to be tested, but does normally allow all items which will become inaccessible to be tested while it is still (relatively) easy to put things right.
3. I personally try and avoid plastic pipe, and prefer soldered copper. Whenever possible I still test to 1.5 times working pressure (which for a combi based system I take as 5 bar) for at least 30 minutes. 5 bar is the maximum working pressure of most plumbing items.
4. I can't see why a Rothenberger RP30 can't be used for the tests you envisage. It will go well beyond 10 bar. The RP50 is perhaps easier to use, and you could probably hire one.

Thanks @steadyon for taking the time / trouble to respond.

So in essence the test would only be the flow and return pipes and 4 x tees, unless i take it further and include piping to the rads. This would mean bypassing each of them locally, which may well introduce new problems that aren’t currently there! The pipework to the rads only sticks out of the wall enough, to get the connector on. Any issues and i’ll have to cut into the wall. :-/
The RP30 restiction I was referring to was the varying load that is required over a period of 15 minutes (?) as per the British standard. There is then a static period thereafter. JG add further requirements, as per what you state. I imagined that the varying load would be done by one of those pressure testers that has a built-in pump, but that is pure speculation on my part.
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How many times are we going around these houses?
Eventually you have to stop asking and actually do it!
As numerous other threads , you’ve been advised to switch to copper in this area...

The main thrust of this question is regarding the pressure testing, which i haven’t asked about before. If i start the job without knowing how to complete it, i am quickly going to come unstuck.
Had decided to go down the path of testing, but then spotted the comment about isolating various components that then threw the decision into doubt / confusion. There was also the pro-video i watched this morning that threw further doubt on the need to test, hence the post.

 

[oz-plumber]

Easiest way is to isolate the boiler with the boiler valves.
Test the rest of the system to 5 Bar.
Bung a test bucket in to a radiator plug or bleeder and test for 30 minutes.

5 bar is not that great of pressure.
If any part of the system fails - it was going to anyway.
Just make sure you isolate the boiler because you may cause damage - they are only rated to 3 bar and you will blow out the pressure relief valve

I should add, I pressure test everything that is altered or added to.
Not only can you charge more for your time on the job, but it does give you peace of mind that there are no leaks.

I've had some disastrous leaks on jobs in the past, but thankfully for me, they have been caused by others.
Nails or screws in pipe are the worst. They hold for some time and then let go.
I haven't had a fitting let go - a few have during testing - but that's why we test!!!!

 

[smallsteve]

Easiest way is to isolate the boiler with the boiler valves.
Test the rest of the system to 5 Bar.
Bung a test bucket in to a radiator plug or bleeder and test for 30 minutes.

5 bar is not that great of pressure.
If any part of the system fails - it was going to anyway.
Just make sure you isolate the boiler because you may cause damage - they are only rated to 3 bar and you will blow out the pressure relief valve

Cheers @oz-plumber!

So just to labour the point, by ‘test bucket‘ you mean the pressure test kit itself? Isolate boiler only and leave all rads / sanitaries / everything else connected? Then connect to any rad on the system (or suitable pipe / anything) and static test to 5-bar’ish for 30-mins? TIA

 

[oz-plumber]

If it were me doing the works:
Heating system - 5 bar - rads and pipework - boiler isolated.
Water supply - 10 Bar - boiler isolated ( cylinder too, depending on what type )

 

[smallsteve]

If it were me doing the works:
Heating system - 5 bar - rads and pipework - boiler isolated.
Water supply - 10 Bar - boiler isolated ( cylinder too, depending on what type )

Would the sanitaries be able to cope with 10-bar, on the assumption that you are suggesting they are left connected? JG quote 10-bar, but they state to isolate as mentioned previously.

 

[oz-plumber]

If you're worried, isolate or turn off taps under mixer taps and isolate cisterns from stop tap, but I wouldn't bother.

I have been involved with testing of water pressures, for say when a washing machine / dishwasher solenoid valve slams shut. For a minimum of 4 seconds, the water pressure in the entire water system to a household increases about 6 times.

5 bar becomes 30 bar instantly for a very short period of time and so on depending on your incoming water pressure.

General reason for water hammer.

We have a regulation of installing 500 kPa pressure reducing valves on properties, but there are many proporties that have no valve installed and there pressures could be beyond 1000 kPa.

So testing sanitary fixtures at 1000 kPa / 10 Bar for a period of time will and should do no damage.
If it does, the product will fail sooner rather than later

 

[smallsteve]

If you're worried, isolate or turn off taps under mixer taps and isolate cisterns from stop tap, but I wouldn't bother.

I have been involved with testing of water pressures, for say when a washing machine / dishwasher solenoid valve slams shut. For a minimum of 4 seconds, the water pressure in the entire water system to a household increases about 6 times.

5 bar becomes 30 bar instantly for a very short period of time and so on depending on your incoming water pressure.

General reason for water hammer.

We have a regulation of installing 500 kPa pressure reducing valves on properties, but there are many proporties that have no valve installed and there pressures could be beyond 1000 kPa.

So testing sanitary fixtures at 1000 kPa / 10 Bar for a period of time will and should do no damage.
If it does, the product will fail sooner rather than later

Thanks for clarifying that. Just wanted to be completely clear on my understanding of your recommendation.

With my engineer‘s hat on, although I am not a plumber as is blindingly obvious, I like your suggested method of testing i.e. leaving most components connected. I am not absolutely confident that the whole system is currently watertight, never mind after i’ve been buggering around with it! Ever since I have moved into this property (some years back) I have had to deal with many issues, albeit on a smaller scale. I recently had to top up the boiler pressure and there was a bit of staining on the walls downstairs. But, I suspect this was the shower that had definitely been leaking for some time. Having said that, there may be more than one leak!

Reckon my best bet is to test the system as you suggest, but before I make any changes. In this way I am starting from a solid base and if any problems manifest thereafter, I know where to look!

Cheers buddy