Mains Cold Water Pressure

[AdrianUK]

Around what pressure should the mains cold water be? I'm seeing around 2 bar at the nearest point that I can measure to the incoming stop cock but the problem is that the cold water cistern fills very slowly & the central heating header tank wont fill at all!

We live in an old Victorian three storey house - the central heating header is in the loft & the cold water cistern is high up in the room below it. I would estimate that the cold water cistern is around 36 feet off the ground & the central heating header about 40 feet.

From memory, 2 bar should support a column of water of about 20m high.... so the upper tank should fill OK.

Any suggestions?

Adrian

 

[HERTS P&D]

Dirt in toilet float valves- remove and clean out dirt.

Supply to expansion tank has stopcock/isolation valve which is closed or faulty float valve.

Andy

 

[AdrianUK]

Thanks for your suggestions:

Replaced ball valves yesterday, also checked rising main for restrictions - none found.

Flow rate on kitchen cold tap is fine so dont suspect restriction of main stop cock.

By 'cistern' I mean the main cold water tank which feeds the hot water cylinder. I started to get interested the other day when daughter managed to empty the tank while having a shower - this has never happened before ..... I sure it used to fill with a much higher flow ....

 

[HERTS P&D]

Have you had any work done on the plumbing that someone might have left a stopcock partly open?

Andy

 

[AdrianUK]

Nope. Only three stop taps in the path (stop tap in street, main tap in rising main in garage & one just below the cold water tank) and all are fully open (dismantled the one below cold water tank - no restriction or blockage found).

Did a pressure test on the pipework this afternoon (fitted gauge to garden tap & turned off supply in street) lost no pressure after 10min (I was wondering if the water pipe had burst under the drive).....

 

[HERTS P&D]

Did you fit a new float valve to your cold water tank in the loft?

Andy

 

[AdrianUK]

Andy,

Thanks for your suggestions so far.

Yes, I did change the ball valve in the loft. I stripped both of the old ones down, expecting to find them seized or blocked. Although both had a good encrusting of limescale on them, the plungers were free to move & followed the arm with no problems. I didnt find anything in the nozzles either.

I guess the thing to try is to fit the pressure gauage to the pipe in the loft & see what the static pressure is with no water being used.

Adrian