Low water level - HHHHHEEEEELLLLLLPPPPP!

[kernowman]

Replaced the pump tonight with a brand new one and it sounds no different to the old - lots of dry sounding noises and great gulps of air/water, suggesting a low water level. This also is supported by never getting water from the upstairs rads while bleeding.

There is plenty of water in the header tank up in the loft. Where exactly in the system does this tank top the water level up?

If the feed pipe from the header tank is blocked, is there an easy way to unblock it?

 

[JohnD]

If you draw a bucket of water off downstrairs, does the header tank replace it? If not, then you're probably right in suspecting a supply pipe blockage. I had that with old hardened sludge. Had to cut out and replace the blocked pipe (it was at a downward bend). Chemical cleaners can't shift it if there's no water flow through th e blockage.

You might consider filling it through the expansion pipe. You may possibly detect the blockage with a temperature difference either side of it.

Or you could open joints until you find one with no flow.

The feed probably arrives in the airing cupbord and will be a 15mm pipe

 

[andsam]

A magnet will stick to the blockage.

 

[kernowman]

I think plumbers are wonderful people to work in such awful confined spaces. Knowing that, why aren't such considerations accounted for during the installation!

After contorting myself into all sorts of positions I think I have traced the route of the feed pipe, which as usual goes BEHIND the hot water tank right in the corner, then follows tight to the wall on the side and joins the main flow underneath it in a parallel path of about 2 inches around the same again above the floor - what a pig! Not a compression fitting in sight from the tank to the feed so can't crack open a joint to establish flow/no flow.

No room to swing a saw or pipe cutter, so the ONLY way to work on it is to remove the entire tank What should be a simple job is turning into a blooming saga. Before I go down that road I'm going to use mains pressure down the feed to try and clear the blockage

 

[meldrew's_mate]

I think plumbers are wonderful people to work in such awful confined spaces. Knowing that, why aren't such considerations accounted for during the installation!

You write the spec. for Building Standards to incorporate, then don't moan when you can't have your airing cupboard here, or it needs to be such &such a size "for accessibility" and there's no room left for your en-suite shower!

Glad to see you're getting to the bottom of it, buy a 15mm isolation ball valve to cut into the cold feed pipe near to the junction. When it happens again you can simply plug the tank & poke-out the blockage with a wire coat hanger or similar.

 

[kernowman]

If only life was that perfect

Drained off half the system today and the water level in the header tank dropped not one single millimetre, confirming it is a blocked feed pipe.

Going to try a double strength mixture of descaler/grunge cleaner for a week or two and hope it may shift it (doubtful) before I decide how to tackle the blocked feed pipe.

Thanks for all your help guys, it is appreciated!!!!

 

[JohnD]

In my case the hardened sediment was where the 15mm cold feed joined the 28mm main pipe in the airing cupboard, I'm told this is where it usually happens. HTH