I have this tank in the roof space. Not sure if it's plastic or
fibre-glass, because it's texture in parts is very uneven, not what I
imagine a moulded PVC tank would usually be like.
There's an obsolete 15mm outlet that used to supply a shower unit. For
some reason, maybe to maximise the pressure, the hole for this outlet
is very close to the bottom edge of the tank, leaving little room for
any flanged fittings that might be used to seal the hole. The current
union with the tank is a male threaded fitting that's just screwed
into the wall of the tank after being wrapped in PTFE tape. I could
try renewing this with fresh tape but I'd prefer to make a more solid
repair. Can anyone suggest an effective method?
Thanks,
--
Bill Haines

In article ,
Bill Haines writes:
I have this tank in the roof space. Not sure if it's plastic or
fibre-glass, because it's texture in parts is very uneven, not what I
imagine a moulded PVC tank would usually be like.
There's an obsolete 15mm outlet that used to supply a shower unit. For
some reason, maybe to maximise the pressure, the hole for this outlet
is very close to the bottom edge of the tank, leaving little room for

It's close to the bottom, so if the tank runs empty, the hot
water cuts off first so you don't get burned in the shower.
Doesn't make any difference to the pressure.

any flanged fittings that might be used to seal the hole. The current
union with the tank is a male threaded fitting that's just screwed
into the wall of the tank after being wrapped in PTFE tape. I could
try renewing this with fresh tape but I'd prefer to make a more solid
repair. Can anyone suggest an effective method?

Difficult. If there's really no room for a flange, then you
are restricted to sealing it on the cut edge of the hole.
I wonder if you can get tubeless tyre repairs that big (the
conical rubber things they pull though punctures to reseal
tyres)? There's a French method of fixing suspended ceiling
lights which works by having a short length of very thick-
walled rubber tube which you push into a close fitting hole
in the ceiling, and then compress lengthwise with a screw
and washers on each side so it swells and grips the hole.
Something along these lines might work, with some sealant to
seal around the screwholes in the washers. Make sure any
sealant you use is suitable for water tanks (i.e. not a
silicone sealant with fungicide).

--
Andrew Gabriel

On Sun, 27 Aug 2006 09:58:35 +0100 someone who may be Bill Haines
wrote this:-

There's an obsolete 15mm outlet that used to supply a shower unit. For
some reason, maybe to maximise the pressure,

The reason is safety of people using the shower.

the hole for this outlet
is very close to the bottom edge of the tank, leaving little room for
any flanged fittings that might be used to seal the hole.

How little room? Is the problem that the flange would strike the
bottom of the tank, or that the radius of the tank wall at the
corner would prevent the flange fitting flush to the wall?


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Bill Haines wrote:
I have this tank in the roof space. Not sure if it's plastic or
fibre-glass, because it's texture in parts is very uneven,
not what I
imagine a moulded PVC tank would usually be like.

If the tank is Black it is probabably a rotationally moulded
Polyethelene (or Polypropelene)Tank. If it is GRP it will probably be
grey and very hard.


There's an obsolete 15mm outlet that used to supply a shower unit. For
some reason, maybe to maximise the pressure, the hole for this outlet
is very close to the bottom edge of the tank, leaving little room for
any flanged fittings that might be used to seal the hole. The current
union with the tank is a male threaded fitting that's just screwed
into the wall of the tank after being wrapped in PTFE tape.

This leads me to believe that it is a Polyeth or Polyprop tank as you
couldnt do this with GRP.

I could
try renewing this with fresh tape but I'd prefer to make a more solid
repair. Can anyone suggest an effective method?
Thanks,
--
Bill Haines

I should leave well alone or replace the tank. It is a bodge that is
holding. As an ex tech consultant to a tank manufacturer I have seen
hundreds of such bodges. The mind boggles at some of the corners that
are cut when fitting such tanks.

On Sun, 27 Aug 2006 10:59:44 +0100, David Hansen
wrote:

On Sun, 27 Aug 2006 09:58:35 +0100 someone who may be Bill Haines
wrote this:-

There's an obsolete 15mm outlet that used to supply a shower unit. For
some reason, maybe to maximise the pressure,

The reason is safety of people using the shower.

the hole for this outlet
is very close to the bottom edge of the tank, leaving little room for
any flanged fittings that might be used to seal the hole.

How little room? Is the problem that the flange would strike the
bottom of the tank, or that the radius of the tank wall at the
corner would prevent the flange fitting flush to the wall?

A little of both I think. I got the proper fitting and cut some off
one edge to compensate. Now it's sealed. Thanks to both you and A G
for the revelation about the reason for the location of the outlet and
other useful tips.
--
Bill Haines

Bill Haines wrote:
I have this tank in the roof space. Not sure if it's plastic or
fibre-glass, because it's texture in parts is very uneven, not what I
imagine a moulded PVC tank would usually be like.
There's an obsolete 15mm outlet that used to supply a shower unit. For
some reason, maybe to maximise the pressure, the hole for this outlet
is very close to the bottom edge of the tank, leaving little room for
any flanged fittings that might be used to seal the hole. The current
union with the tank is a male threaded fitting that's just screwed
into the wall of the tank after being wrapped in PTFE tape. I could
try renewing this with fresh tape but I'd prefer to make a more solid
repair. Can anyone suggest an effective method?
Thanks,
--
Bill Haines

If its an obsolete outlet why not just drain the tank and clean the
hole, let it dry and fill that threaded hole with a bung of araldite.
that will stop any water coming through there.
If you try to repair it you might not succeed.
Incidentally putting the hole low in the tank is done to maximise the
water storage. Many plumbers put the outlets well up the wall of the
tank and you have a much more limited capacity than you imagine if
there was a mains failure.
If you had a poor main feed a decent capacity tank is vital especially
if there are others drawing on it at the same time.

wrote:


If its an obsolete outlet why not just drain the tank and clean the
hole, let it dry and fill that threaded hole with a bung of araldite.
that will stop any water coming through there.

Do not try and try to fill the hole with Araldite if it is a black poly
tank. It wont adhere.