Sludge from water tank in loft has blocked pipe?

[dorset54]

About 2 weeks ago, I discovered a hairline crack about 1/4 way up water tank in loft (causing a wet ceiling).
A plumber has been out to measure up to replace tank, but is busy until next week.
I have, so far, been "managing" the crack in the loft tank by maintaining the water level so that it doesn't seep out of the crack.
I haven't let the water level fall below the top of the outlet pipes.
Except for when I did some laundry (6 days ago) and had to leave the mains tap (under the kitchen sink) running, the water level in the loft tank has not risen much above the crack, just to ensure there is sufficient to replace the amount of water in the hot water cylinder after a bath has been run.
I have been scared of letting it get too low, being fearful of the consequences of an airlock in the pipes.
However, when the level in the loft tank is low, the incoming water does rather stir up the sludge in the bottom of the loft tank.
This morning, the bathroom basin tap stopped running.
There is no water from the cold tap on the bath and the toilet cistern doesn't fill.
So I have no water supply to or from either cold tap in the bathroom and the toilet cistern.
I guess the sludge in the bottom of the loft tank has got into the outlet pipe to the cold system and blocked it?
This has put me in a state of despair and fear.
Added to this are fears that sludge has entered the pipe from the loft tank to the hot water cylinder.
I'm thinking that, to switch on the gas boiler, to heat the water, if the hot water cylinder is not full, would be a major disaster.
Do you know if there is any way I can unblock the loft tank outlet pipe?
Do you think I dare run the risk of running a bath from the hot water cylinder to see if there is still a water supply from the loft to the hot water cylinder?
How dangerous is an empty hot water cylinder?

 

[Nige F]

Unlikely that the sludge - sediment from the water main - would have blocked a pipe withoerut showing its self in the bathroom as soup from the tap - you got an airlock Hot water cylinder doesn`t empy it remains full of water until more flows in and displaces existing - it ALWAYS is full .

 

[JohnD]

the hot water cylinder will not become empty just because you run the taps with no supply to it. The taps are fed from the TOP of the cylinder so they stop working when it is still full.

it is rather unusual for a pipe to a cylinder to block up with sediment, your cold tank must have been really bad and full of scale, or maybe rust, or bits on insulation detritus. What colour was the stuff in it?

if it is sediment, it can probably be blown back out by putting a hose between the kitchen cold tap (mains pressure) and a hot tap, so the cold water squirts up the pipe in the opposite direction to usual. This method will also dislodge an airlock, which as Nige says is more likely.

You can remove sediment from a cold tank by running the water out, then scooping it out with a dustpan and brush, followed by sponging it clean. The tank ought to have a lid on it (as well as an insulating jacket) to keep dirt and wildlife out of it. If your old tank is cracked, easiest thing is to fit a new plastic tank with lid and jacket.

 

[Nige F]

Go On John , Hants .is nearer to Dorset than Sussex. I`d offer myself for a nice little job like that

 

[JohnD]

A plumber has been out to measure up to replace tank, but is busy until next week.

 

[dorset54]

Unlikely that the sludge - sediment from the water main - would have blocked a pipe withoerut showing its self in the bathroom as soup from the tap - you got an airlock

The water has been clear.
I was thinking air couldn't have got into the pipe, because I hadn't allowed the water level to drop below the top of the outlet. Though I guess water is displaced by incoming water splashing around, when the level is so low.

Hot water cylinder doesn`t empy it remains full of water until more flows in and displaces existing - it ALWAYS is full .

Thank you so so much!!!!! I had got really upset, thinking I had to stand at the sink with a flannel and just have a wipe down. Now I've bathed and washed my hair, I feel much more human.

the hot water cylinder will not become empty just because you run the taps with no supply to it. The taps are fed from the TOP of the cylinder so they stop working when it is still full.

Thank you so so much!!!!!!! Please see above.

it is rather unusual for a pipe to a cylinder to block up with sediment, your cold tank must have been really bad and full of scale, or maybe rust, or bits on insulation detritus. What colour was the stuff in it?

There's a very thin coating of fine sand, sediment (or rust?) on the bottom. It's a bit stirred up now I've had my hand in there. And there are thin white slithers of limescale?

if it is sediment, it can probably be blown back out by putting a hose between the kitchen cold tap (mains pressure) and a hot tap, so the cold water squirts up the pipe in the opposite direction to usual. This method will also dislodge an airlock, which as Nige says is more likely.

Perhaps it is an airlock? Trouble is that the kitchen has a mixer tap.

You can remove sediment from a cold tank by running the water out, then scooping it out with a dustpan and brush, followed by sponging it clean. The tank ought to have a lid on it (as well as an insulating jacket) to keep dirt and wildlife out of it. If your old tank is cracked, easiest thing is to fit a new plastic tank with lid and jacket.

But I thought that I would create an airlock, if I completely emptied the tank? The tank has a lid. I removed the jacket to find the hairline crack, which is more like 3/8 up from the bottom than 1/4.

I forgot to mention that a tiny flow of water comes out of the bathroom cold taps intermittently.
Thanks again, both of you.

 

[JohnD]

if you leave the tap on, and it is dribbling, then it will probably clear the airlock in time. Or sometimes they clear themslves.

is the bathroom cold tal at mains pressure or from the tank?

 

[dorset54]

if you leave the tap on, and it is dribbling, then it will probably clear the airlock in time. Or sometimes they clear themslves.

is the bathroom cold tal at mains pressure or from the tank?

Thank you. I'll give it a try. It is from the tank.

EDIT: The cold tap on the bath trickles, but there's chuff-all from the basintap or into the toilet cistern. But the reassurance to bath is greatly appreciated.

 

[looneyfitter]

Could also be loose lagging sludge that has entered the tcws pipework (hot and cold feed) and partially blocking it. Ask your plumber to connect the two valves at your washing machine together and cap the expansion (ensure this is un capped). Turn the wash mashine taps on and if he gets water filling back into the tank than you will have cleared any airlocks and hopefully blew any crap back out.

Also tell him to do the same to the bath tap CWS (may need to use a hose from the MCWS) to blow anything out that may have entered the cold.

Also make sure he converts your tanked CWS to MCWS. You will then have Potable water for drinking at the basins.