Help with replumbing leaking heating system

[Wexbike]

I have a pdaily loss of pressure in a closed circuit system as noticed on the gauge at the filling point 2 bar to 0. After exhausting all the usual options it appears there’s a leak unground with no visual sign anywhere.I’ll have to re plumb the heating. The boiler feed and return pipes are about 20 metres away. I’ve googled pipe depths…insulation required and pipe type, I guess it’s 22 mm pex is the type I’ll use. I’ve googled pipe depths…insulation required etc what is the actual type of insulation and and trench depths recommended.
Also As it stands there’s no bypass valve from flow to return only a prv at the boiler. On a closed system is the pressure tank always on the flow side.
Does it matter if the rad feeds are connected as it comes in from outside before the immersion tank flow and return.
It a simple arrangement with 6 rads downstairs. And two upstairs in series.
I’ve fixed leaks an installed pipes before but I need some guidance to give me confidence.
Thanks, sorry about the long question.

 

[Maryplumb]

Before you assume your system is leaking get a gas engineer to check the boiler. They will also advise you about the bypass etc. There are rules about pipework near the boiler so don't attempt this without the necessary knowledge. There are also rules about which branches to tee in first to a heating system.

 

[SimonG]

As above, you need confirmation it's the system and not the boiler.

Sounds like sealed heating system, vented hot water tank? Could be cylinder coil pin holed.

Also sounds as though you are out of your depth as far as the repipe goes, your plan could cause lack of control to heating/hot water system, reverse circulation, breaching part L building regs.

Get somebody in to check out the system, if it does need a re pipe then you can always dig trenches etc to reduce costs etc.

 

[Wexbike]

Thank you for that. It’s an oil burner should be ok to work on. I’ve plumbed pipes to repair leaks before. It’s finding the leak is my problem. Because of that I may have to re plumb the whole system putting a new set off feed and return pipes outside.
Thank you again

 

[Wexbike]

As above, you need confirmation it's the system and not the boiler.

Sounds like sealed heating system, vented hot water tank? Could be cylinder coil pin holed.

Also sounds as though you are out of your depth as far as the repipe goes, your plan could cause lack of control to heating/hot water system, reverse circulation, breaching part L building regs.

Get somebody in to check out the system, if it does need a re pipe then you can always dig trenches etc to reduce costs etc.

Much appreciated I’ll probably run with that plan.

 

[buenoplumbingca]

When you presume your system is leaking, have your boiler inspected by a gas professional. They will also provide you with information regarding the bypass and other options. There are laws against repiping in San Jose, so don't try it unless you're sure you know what you're doing. There are additional regulations for which branches of a heating system should be teed in first.