Hot water with unpressurised CH system..?

[AWJS01]

Hello,

I'm going to have to replace the filling loop on my Sime 90 combi boiler, or at least the non-return valve that connects to the CH return pipe.

The heating is currently at 0 bar - can I still use the hot water in the meantime, or am I missing something with regard to the 'sealed' CH idea?

On the subject of filling loops - do the regulations now specify the 'R24' version, and what's the difference between this and the older type?

Thanks!

Alan.

 

[oilman]

Heating and hot water have no physical connection, so the system pressure is not relevant.

The new filling loops have a stop valve at each end, but the double check valve is on the mains side now and not on the appliance side. This is because loonies were using the filling loop connection as a convenient water connection for other purposes. The problem with the new ones is you have to remember to shut both valves before you disconnect the loop ot water gushes from both connections.

 

[AWJS01]

...for the quick reply. I'll go wash the dishes then!

Alan.

 

[BelgraveHeating]

Some combi's when the pressure falls to a certain level will not fire up on either hot water or heating (it is a safety function).
However Oilman is right most will still fire up.

 

[AWJS01]

So the filling loop I have at the moment has a (slightly leaky) ball valve at the mains end and the (very leaky) non-return valve (is this the 'double-check' valve your refer to?) at the boiler end.

When I disconnct the filling loop I get the central heating water pouring out via the non-return valve at the boiler end. I can't turn this off, and I can't get a proper water-tight connection with a stop-end as I'm having to screw it on with water squirting out.

Does this make sense? I'm a little bit surprised that the non-return/double-check valve doesn't work any more - should I be?!

Cheers,

Alan.