At my wits end

[Derrick Brown]

Completely isolated, not connected, open ends at the joints going to them (I used push fit elbows to connect them, removed them put cap ends on the pipe work feeding them from the boiler

So yes completely isolated

I have read the paper work on ferric, it says it doesn’t clog heat exchangers, in fact they recommend it for combo boilers

 

[terryplumb]

Completely isolated, not connected, open ends at the joints going to them (I used push fit elbows to connect them, removed them put cap ends on the pipe work feeding them from the boiler

So yes completely isolated

Ok ,all good there.

 

[Derrick Brown]

I have also checked the valves, in case they were weeping, wrapped them in a paper towel (seems that will show any water leaking from em)

Now common sense tells me, if water is leaking, it should show somewhere

 

[MeldrewsMate]

Hire a hydraulic test pump (ask if you want to go this route, others are more capable than me of showing you a picture of a suitable pump), isolate the boiler at both flow and return, isolate its gas and electrical supplies.
Bleed all rads of air.
Connect the pump to one of the conservatory feed pipes (it seems a convenient place to connect).
Pump up to 5 bar. Does the pressure hold for more than a minute?
Pump up to 8 bar. If the pressure holds greater than 30 minutes then your pipework and rads are sound.
If it drops, inspect all accessible joints AND THE FRONT AND BACKS OF ALL RADIATORS. At those pressures any cracks and pinholes in radiators and pipes will show up, and it only needs a little fluid loss in a sealed hydraulic system to show a perceptible pressure drop.

Was the pipework to the conservatory properly wrapped to protect it from chemical attack, and to allow for expansion? It is surprising how quickly cement can rot unprotected copper.

 

[Derrick Brown]

Right going to have to answer this bit by bit

The pipe work in the conservatory is John Guest plastic with push fit fittings (the ones that twist and lock) it was wrapped in insulation, I wanted the heat in the rads, not under the floor, but that is completely isolated

I have used a hydraulic pressure tester when I was working, they aren’t so good on heating systems, as far as I know the mains water pressure is sufficient for test for leaks, (going back a few years I could get 1.5 bar)

My boiler can measure the pressure up to 3 bar

If I fill it to that then it comes out of the safety valve

I am not sure what my rads are rated at, but 8 bar seems very high, I’m not even sure the pipe work or boiler would take that

 

[endecotp]

On a system with a 3 bar PRV, I believe you’re supposed to test at 4.5 bar. That may be just the pipework with the radiators disconnected.

I bought a cheapo manual hydraulic pressure tester from eBay. It’s absolutely fine for occasional use. and easier than trying to hire one.

 

[Derrick Brown]

Okay, I’ll have a shufty on eBay, just thought I should add I have thermostatic valves all round, except the bathroom towel rail

can’t do much until Monday now

If possible I’d like anyone’s views on the Fernox, has anyone used it ?

 

[MeldrewsMate]

If I fill it to that then it comes out of the safety valve

I am not sure what my rads are rated at, but 8 bar seems very high, I’m not even sure the pipe work or boiler would take that

That's true, which is why I wrote this....

... isolate the boiler at both flow and return, isolate its gas and electrical supplies.

Isolate the boiler from the system, then you are pressurising just the pipework and rads.
NOTE: the pressure gauge on the boiler will not be of any use in this test, there will be a pressure gauge on the hydraulic test pump.

 

[stuwa88]

Hey Pal, what I would do is stick a pressure gauge on the pipe you cut and capped to the conserv radiator. Then pressurise the system via the boiler and close the flow and return to the boiler and you now have the boiler and radiator pipe work separate and with their own gauge. That should help narrow it down for you (hopefully both don’t drop haha!) If it drops on the pipe work side then I would isolate radiators 1 at a time via the valves and repeat the test with them all to see if the leak is on the rads or the pipes if it’s the pipe work then I’m afraid you might have to go crawling about under the floor.. as for the boiler side it sounds quite tricky because you say you have checked a lot of the things I would say such as: blow off, heat exchanger, condensate, expansion vessel.. I would be interested to hear how this is resolved!

 

[stuwa88]

I forgot to mention.. this is the type of gauge I was meaning - maybe connect it with a washing machine valve (without check valve)
https://www.screwfix.com/p/rothenberger-water-pressure-test-gauge-10bar/53626

 

[stuwa88]

Did you check your drain for the system isn’t dripping?

 

[Derrick Brown]

Now that is an idea with the gauge

I have had floor boards up traced pipe work, checked all the drops, tried shutting off all the valves (see if it dropped in the pipe work)

I was hoping there might be a pin holein a rad, or the pipe work in the conservatory (I can dig that out easy enough, it’s not that deep, just a shallow skin with laminate flooring over the top (that will be harder get up)

If I could just find a damp patch or a puddle of water, it would really help

 

[Derrick Brown]

Found it at last

Drain cock outside, letting by

Not sure if it’s the rubber washer inside that needs replacing but going to have to drain the system to check or replace it

Would have never noticed, there was just a damp patch beneath it (it has been raining a lot so just never noticed it)

oh well these things are sent to try us