On 10 Aug, 22:29, lister wrote:
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

The gate valves are usually about 4 or 5 turns fully open to fully
shut. It's quite likely they are corroded up and can't be fully
opened/closed. Also the valve seats are quite likely corroded too &
the valve won't shut off tight.

You may have air in the sytem. Assuming you have a traditional tank
in the loft system. In the kitchen get a short piece of hose pipe and
join up the hot and cold taps. You may need assistance to hold the
hoses in place.
Turn on the hot tap and then the cold tap. High pressure mains water
will go into the hot sytem and displace any air. lesve it run for a
minute or so. Turn off the cold tap first and then the hot or you may
get a bit wet.