On Mon, 13 Oct 2008 23:40:44 -0700, Clive wrote:

Hello,

I have an indirectly (?) heated CH/DHW system. There is a boiler,
cylinder (hot water tank), pump and two ACL Lifestyle motorised
valves.

1. I drained down the system at the drain tap. When I tried to re-
close the system the tap kept on leaking. I took out the whole of the
inside of the drain plug and replaced the flat, circular rubber washer
having removed the old one. The drain tap still leaks, even though I
have tightened it. Any other ideas on how to tackle that?

Bits of the disintegrated old washer still stuck in the valve preventing
the new washer seating properly? Rubber washer over-tightened when system
hot and squeezing off its seat? (Usually ****es out if you do this.)
Failing that replace the DOC.

2. I replaced a couple of radiators and the CH does not heat. The DHW
is fine. The radiators and pump are bled. I can feel scorching hot
water from the boiler as it enters the pump. When DHW is set to on,
the 22mm pipe below the valve on the DHW cylinder side of the circuit
gets hot. The water pipe downstream of the valve on the CH side does
not get hot even when the boiler is generating hot water and system
set to "on" for CH. I guess this is a valve problem. Anything I can do
to check the operation of this valve? Is this an easy part to replace?

There's a lever on the valve to open it manually - try that. Otherwise it
suggests an air-lock somewhere preventing hot water circulating around the
rads. Is there an air bleed valve on a vertical leg of pipework somewhere
you've missed, or an automatic air bleed valve that's got its dust cap
screwed down or is not automatically bleeding? (Try loosening its screwed
cap to see if that lets air out.)


3. One of the radiator valves leaks slightly. The valve has a push fit
on the supply and two threaded parts on the body of the valve. One
thread screws into the body of the radiator and the second thread
connects the body of the valve to the section that screws into the
radiator. It is this middle thread that connects the valve to the pipe
going into the body of the radiator that leaks. I took the valve apart
and saw the thread was fairly "shallow". Also the conection between
the two parts was like a "shallow bowl". I cleaned the surfaces and
wound a fair amount of PTFE tape around the thread. I reassembled the
valve. I hand tightened, then tightened with a wrench as far as I
dare. There is still a very slow leak - say one drip every 30 (?)
minutes. The way I would describe the leak is that is the water is
coming "up and over" the nut rather than "down and around" the nut.

It's a compression fitting, with an olive (like a plain wedding ring) on
the tubular section of the 'tail' that screws into the rad. The olive can
be set at a range of positions along the tubular bit. Have you got it
right at the end, almost off the tube? It should be far enough along that
there's some of the tube sticking into the mating part of the valve body.
(Have a look at how any other compression fitting works so you know how
it's supposed to be.)



--
YAPH http://yaph.co.uk

Things don't like being anthropomorphised.