I tried replacing an old-style ballcock valve with a quiet fluidmaster
side fitting float valve to reduce refill noise. Can someone please
explain how a reliable seal can be obtained? I fitted a 1/2 inch quad
plex pipe into the valve with a fibre washer. I then hand-tightened
according to the instructions (as hard as I could to be on the safe
side). This seemed to work until I turned the mains on fully and tested
the valve on/off a few times and the service pipe just popped out of
the valve fitting. I'm pretty sure I had the plastic nut correctly
threaded all the way onto the plastic thread on the valve.
I understand how standard compression fittings work, i.e. the insert
fits into the pipe allowing you to tighten the metal ring onto the pipe
without the pipe caving in, then the metal ring forms a tight seal
between the nut and the connector. With just a fibre washer in place of
the ring I just don't understand how this can work with 100% reliably
with no chance of the service pipe popping out of the fitting.

I saw no reference to high or low pressure in the installation
instructions but it is supposed to be able to work in an attic storage
tank, which I presume will almost always be at mains pressure. The
instructions didn't have any reference to any other rings or anything
so I have no idea what I did wrong. Obviously I don't want to flood my
house so I won't try a stunt like this unless I'm certain it's
completely safe!

Thanks in advance for any assistance.
Chris.

In article om,
"Chris" writes:
I tried replacing an old-style ballcock valve with a quiet fluidmaster
side fitting float valve to reduce refill noise. Can someone please
explain how a reliable seal can be obtained? I fitted a 1/2 inch quad
plex pipe into the valve with a fibre washer. I then hand-tightened
according to the instructions (as hard as I could to be on the safe
side). This seemed to work until I turned the mains on fully and tested
the valve on/off a few times and the service pipe just popped out of
the valve fitting. I'm pretty sure I had the plastic nut correctly
threaded all the way onto the plastic thread on the valve.
I understand how standard compression fittings work, i.e. the insert
fits into the pipe allowing you to tighten the metal ring onto the pipe
without the pipe caving in, then the metal ring forms a tight seal
between the nut and the connector. With just a fibre washer in place of
the ring I just don't understand how this can work with 100% reliably
with no chance of the service pipe popping out of the fitting.

I'm having difficulty picturing what you're doing, but it sounds
like you are somehow trying to connect up the pipe directly
without using a 1/2" tap connector. Maybe you discarded the tap
connector with the old ball-valve? The fibre washer is to seal
against a tap connector. Here's an example tap connector with a
pipework compression fitting: http://www.screwfix.com and search
for item 18526

--
Andrew Gabriel

Hi Andrew,
Thanks for the reply. To clarify my post I'll refer to the diagram
http://84.203.164.145/fluidmaster.jpg

The supply line is my quadplex mains feed.
The 'tap connector' is a 1/2" compression nut.This is my mistake, it
looks like a compression nut in the diagram but the picture of the tap
connector you referred to looks very different.
The 'washer' is a fibre washer.

The 'Shank' fits through the tank wall and I was sitting the service
pipe directly into it and tightening the compression nut onto it with
the fibre washer inside.

In hindsight I can see that this couldn't possibly work reliably under
mains pressure but the installation instructions are really crap, the
diagram is very misleading IMHO. I guess they are assuming the
installer is a qualified plumber which is dangerous for something
marketed as a DIY product.

Thanks a lot for the advice,

Cheers,
Chris.


I'm having difficulty picturing what you're doing, but it sounds
like you are somehow trying to connect up the pipe directly
without using a 1/2" tap connector. Maybe you discarded the tap
connector with the old ball-valve? The fibre washer is to seal
against a tap connector. Here's an example tap connector with a
pipework compression fitting: http://www.screwfix.com and search
for item 18526

--
Andrew Gabriel

On 2006-12-07 19:24:03 +0000, "Chris" said:

Hi Andrew,
Thanks for the reply. To clarify my post I'll refer to the diagram
http://84.203.164.145/fluidmaster.jpg

The supply line is my quadplex mains feed.
The 'tap connector' is a 1/2" compression nut.This is my mistake, it
looks like a compression nut in the diagram but the picture of the tap
connector you referred to looks very different.
The 'washer' is a fibre washer.

The 'Shank' fits through the tank wall and I was sitting the service
pipe directly into it and tightening the compression nut onto it with
the fibre washer inside.

In hindsight I can see that this couldn't possibly work reliably under
mains pressure but the installation instructions are really crap, the
diagram is very misleading IMHO. I guess they are assuming the
installer is a qualified plumber which is dangerous for something
marketed as a DIY product.

Thanks a lot for the advice,

Cheers,
Chris.


On other tip (once you have the correct tap connector) is to leave
the locknut of the valve loose while you locate and screw the nut of the tap
connector onto the shank of the valve. Plastic threads on these valves
are not very substantial and it's very easy to put the nut on cross threaded if
the pipe is not in perfect position and alignment. The result is
stripping of the thread
and then the valve is destined for the bin.
Having it loose to begin with allows you to align the pipe and shank
and screw on the
tap connector nut - finger tight.
Then tighten the locknut and finally the tap connector nut.