Check valve Question

[ijc]

Can any of you guys tell me what the little nut on a check valve is for?

eg.

I was having trouble with the filling loop for my combi whereby the tap wouldn't close easily thus allowing pressure to rise in the central heating.

Without thinking I tried turning the nut on the check valve clockwise in the hope it would shut off the flow. (Eventually I persuaded the tap in the filling loop to shut OK anyway....)

I hope I haven't done something that will affect the function of the check valve. Don't want dirty water in my taps!!!

Grateful for your thoughts.

Ian

 

[Gasguru]

Its a test point to check if the one of the check valves is operating correctly ie not allowing reverse flow. It should be left fully tightened.

The loop should be disconnected (and the fittings capped off) to comply with water regulations but be carefull since many filling loops are of poor quality and are incorrectly fitted and if the check valves don't work properly you could get very wet by doing this.

 

[ijc]

Nice one, cheers. I tightened it a bit so seems like good news.

I can vouch for the fact that some filling loops are poorly made. The plastic lever on the tap came off in my hand the first time I used it, and like I mentioned, you need the feel of a surgeon to find the position where it shuts off completely.

As ever, thanks for your help and advice.

Ian