Pressure reducing valve as combi top up

[JohnHarrison]

The guy who fitted my Vokera SE said that one installer who operates locally always fits a cheap pressure reducing valve with a double check valve filling loop permanently connected to the water mains and sets the valve to 1 bar. He instructs the user how to bleed the radiators and the valve automatically tops up the pressurised system to 1 bar. He never has call backs because of low pressure saving money and time and it is easier for older people. Is this a legal way to do it? It sounds a great way to maintain the pressure in the system. Every combi system I have seen has the loop flex pipe permanently connected and the user just turns the tap to top up to 1 bar. I believe the flex is supposed to be unconnected or loose after filling. Is that so?

If you have a permanent leak you will know it because of leaks like a normal vented system.

 

[Onetap]

Is this a legal way to do it?

No, it contravenes the Water Regulations.
I don't recall the details off-hand, but the heating system contains a contaminated fluid. The only legal way to connect it to the mains is with a pressurization unit (break tank and pump) or an RPZ pressure reducing valve arrangement. The latter is expensive.

Every combi system I have seen has the loop flex pipe permanently connected and the user just turns the tap to top up to 1 bar. I believe the flex is supposed to be unconnected or lose after filling. Is that so?.

Yes.

If you have a permanent leak you will know it because of leaks like a normal vented system.

You probably wouldn't know. Modern boilers are much less tolerant of leaks and sludge than the old cast-iron things. A hidden leaks is a sure-fire way to kill one off.

 

[JohnHarrison]

Is this a legal way to do it?

No, it contravenes the Water Regulations.
I don't recall the details off-hand, but the heating system contains a contaminated fluid. The only legal way to connect it to the mains is with a pressurization unit (break tank and pump) or an RPZ pressure reducing valve arrangement. The latter is expensive.

Every combi I have seen has the filling loop permanently connected and the user tops up. So most install contravene the laws. I would think the pressure reducing valve is a nice addition to ensure no over pressurisation. The user can then turn it on for a half and hour and not look at the gauge and then off. But that still contravenes the laws, but it is just what everyone else does.

A clever touch from that installer to stop call backs, even if unlawful.

 

[sooey]

All it would take is a leak under the floor and somebody to leave the filling loop open.
Then you've got constant fresh water entering the system, and the gauge won't show it and the boiler will keep going, till it's full of cr*p and dies.
Good idea.

 

[JohnHarrison]

All it would take is a leak under the floor and somebody to leave the filling loop open.
Then you've got constant fresh water entering the system, and the gauge won't show it and the boiler will keep going, till it's full of cr*p and dies.
Good idea.

That would be the same with a top tank in the loft would it not? I am not saying two wrongs make right.

 

[Onetap]

That would be the same with a top tank in the loft would it not? I am not saying two wrongs make right.

Yes, and when the floor-standing cast-iron natural draught boiler got scaled up, it started kettling, you descaled it and started over again.

Boilers have changed somewhat and don't hold as much limescale as they used to.