"lister" wrote in message
...
Hi folks,

I had to change a sink today with no isolation valves on the taps, so
I had to shut off the water.

First turned cold off at rising main.

Looked in airing cupboard to be confronted by one tap like valve just
like the rising main, and three red wheel valves (gate valves?).

Couldn't work out which one stopped the hot, so turned em all off, and
ran a lot of hot taps until they slowed to a stop. All hunkey dorey.

After cutting the tap feed pipes, I was half way through fitting some
isolation valves when there was some ominous gurgling in the system
and a second later I got a four foot jet of water out of the hot pipe!
This cycle then kept occurring approx every 30 seconds or so while I
battled to fit the isolator!

After new sink in place I turned everything back on again. The problem
I now have is that the hot feed is spluttering / low pressure from
most hot taps in the house. Sometimes it's normal, sometimes it slows
to a trickle. I assume I have air in the system.

My questions therefore a

1) If I leave the hot taps running will they sort themselves out?

2) Can I have gotten air in the cylinder? It is dangerous to turn the
cylinder on to heat if this is the case? Is there any way to tell?

3) The red gate valves don't seem to turn very far (maybe half a
turn). Is this right or have I knackered em?

Many thanks,
Lister

There should be a vent pipe in the top of the cylinder running up to
overflow to the tank in the loft (assuming we are talking about traditional
house and system: I bow to other writers if not.), so air should work its
way out that way. If your pipes run a particularly circuitous route you may
have more trouble getting the air out. Sometimes there may be enough play
for you to shake the pipes a bit *with all the taps *turned off**, then you
may be lucky and hear the glugs in the tank as the bubbles work their way up
and out. If you try this with the taps on, the bubble will try to travel
down, but probably end up staying still.

The gate valves: http://en.wikipedia.org/wiki/Gate_valve should have
several turns on them and they are very often stuck. They are meant to be
fully open or fully closed. Sounds like yours were only partly open, and
are now covered in crud. If not fully open they can rattle - until crudded
at any rate -, but if turned out hard they get stuck, and commonly the end
snaps off next time you try to close them. They are very prone to getting
stuck and leaking yet very cheap to buy at your local plumbing suppliers.

What you should do is get yourself some new gate valves. Tie up the ball
valve on the loft tank - bungees are good for this - (especially if the
inlet has another stuck gate valve for the cold supply: if you need to
replace that one you will have to turn off the cold supply further back.),
and open all your hot taps until they stop, and leave them open for any
water that is suddenly released when you start replacing the valves. If you
have an old system you may have hassles replacing imperial sizes with
metric, in which case you may find it easier to replace the lengths of pipe
that have the valves in rather than trying to bodge old to new. If you have
managed to change a sink, you should be able to change these valves without
too much trouble - though working in confined cupboards full of pipes can
always present you with them! (Start with the highest valve to minimise any
spills.)

S