PRV to maintain sealed system pressure

[Doctor Drivel]

I was talking to an engineer a few days back. He has small leak on his CH system and the pressure would drop in 1.5 weeks locking out the boiler on low pressure. This always happened when he was away on a job for three weeks and the wife couldn't re-charge. He has tried to find the leak on the system a small weep somewhere, or a few of them.

He just can't find it/them after looking for months. So he fitted a PRV on the filling loop with double check valve before it, so two double check valves and left it open. He set it to 1.25 bar and he says it just stays at 1.25 bar, topping itself up when need be. I told him it was illegal, but he says the regs can find the leak then, because he can't.

Anyone ever seen this before?

 

[Gasguru]

In the past several companies sold a combined filling loop and presure reducing valve (and maybe some still do) primarilly to save time initially filling the system (saves running to the boiler to top it up).

All however are illegal unless a type CA reduced pressure zone valve is fitted to prevent backflow.

As for the leak - he should just get it fixed - constant top ups will kill the system.

 

[Doctor Drivel]

In the past several companies sold a combined filling loop and presure reducing valve (and maybe some still do) primarilly to save time initially filling the system (saves running to the boiler to top it up).

All however are illegal unless a type CA reduced pressure zone valve is fitted to prevent backflow.

I am aware of these. He fitted and extra check valve, making two to prevent backflow. It is a cheap way of making an auto filling system though, even if you make up your own temporary one.

As for the leak - he should just get it fixed - constant top ups will kill the system.

I told him that, but he has tried in vane to locate the leak. He is in a soft water area so the water is not so aggressive. He will top with X-100 every two years, so he says.

 

[Gasguru]

Check valves (any type) are not approved to prevent backflow of a category 3 fluid to a catagory 1 fluid and is illegal.

For an engineer he's a ****. Thats a significant leak on the system. There are still minerals in soft water that will deposit in the heat exchanger.

As a last resort Fernox leak sealers do appear to work quite well although I've only used them a very slight leaks where pipework is imposible to get to.

Wind pressure to 2.5 Bar, locate, and fix it.

 

[Agile]

Its not hardness in the top up water that causes the main problem.

The main problem is as a result of a continual flow of water saturated with oxygen which oxidises the iron in the radiators.

Its very foolish for anyone who should understand technicalities to waht to do anything like that.

Perhaps he is not such a good "engineer" ?

Tony

 

[Doctor Drivel]

Perhaps he is not such a good "engineer" ?

One with not much time on his hands, that I do know. He said next time he will fit an F&E tank