Tank connectors - apply sealant to washers?

[scubapete]

Hi,

In the middle of hooking up a new cold water cistern. The kit came with a tank connector with a rubber washer for the inside and plastic washer for the outside.

The instructions say just assemble it and screw it up. It looks a bit dodgy though - is it best practise to dose a load of silicone sealant on the washer and tank connector before hooking it up in a similar fashion to a bath waste?

Of course, that means not filling the tank for 24 hours while it sets..

Thanks in advance.

 

[hi-spec plumbing heating]

no need for silicone.

 

[scubapete]

Cheers.

Is there a rule of thumb for tightening connectors? i.e. hand tight, then quarter or half turn?

I though I had compression fittings sussed with a few from wickes, nice and easy to make one whole turn. Then I bought some from my local plumbers merchant and j***s, I could only manage to get half to three quarters of a turn and the thing was pinging like crazy.

 

[hi-spec plumbing heating]

>hand tight, then quarter or half turn?

quarter to half should be ok.

>I though I had compression fittings sussed

use some jointing compound.

 

[scubapete]

Or speedfit...

 

[hi-spec plumbing heating]

your choice
i prefer hep 2o over speedfit.

 

[scubapete]

I'm thinking of it from a diyer angle. It's very nerve-wracking putting all this stuff together for the first time and worrying about whether its under or over tightened etc.

The worry with joints is will there be a leak, right?

Now, assume you make a joint, put the water back on and check for leaks over the next few days as you use the shower/bath/etc and there are none.

Is there essentially any difference between compression and speedfit/hep20/polypumb etc in this situation?

From reading other posts on this controversial issue it seems that with push-fit there is always a (minimal?) risk of catastrophic joint failure (it pops off) or the o-ring perishes over time.

In comparison, will compression fittings be sound forever (effectively)?

 

[hi-spec plumbing heating]

compression are better in the long run as all parts are metal and not plastic with rubber seals.

a plastic fitting can blow off as with a compression fitting if you get a slight weep give it a slight tighten.

i always say never tighten to much as you can always give it a nip up after
but if you over tighten you crush the olive then you'll have to start agin.

 

[scubapete]

Great tip, sounds like the best way to approach compression fittings - do it up half a turn, turn on water and then tighten to stop dripping. There's no way you can over tighten and you can see with your own eyes that it's waterproof.

 

[Symptoms]

Call me old fashioned but ... in loft spaces (& I'm assuming the cold tank is going in your loft) we always like to use soldered fitting where possible. Why? There's always a chance that in a severe winter the water in any pipework up there may freeze, expand and push apart the fitting (push-fits AND compressions); the real scary one of course is the rising main. Not a problem whist still frozen but just wait for the thaw - mains pressure water squirting everywhere, collapsing ceilings, ruined furniture & fittings, etc. etc. In my time I've come across about 5 of the above situations - all caused by pushed apart compression fittings. So, always try to avoid joins, fashion bends with a bender and if the installation in the loft can't be run like this use minimum number of fittings (solder).

 

[scubapete]

Isn't this what insulation is for? Would making sure that all pipes are properly lagged and covered minimise this risk?

There's also a catch-22 in that I've bought an aqualisa axis digital shower pump and this strongly advocates a loft insulation. But they provide push-fit connections for the inlets and outlets AND stipulate that the unit must not be covered with insulation. Talk about mixed messages.

 

[Symptoms]

Insulation? The 5 disasters all had insulation installed - loft insulation over pipes, all pipes covered, but Jack Frost still got in. 3 of the 5 left the CH on, the other 2 hadn't.

For what it's worth, when I go away at Xmas for a week I turn it all off, including the one in the street; I don't want to be presented with a disaster when coming home.

 

[scubapete]

I turn it off at the street also.

When my brother stayed for a week whilst moving house, I went away for a long weekend and he couldn't figure out how to turn off the mixer tap so ran downstairs and shut off the main stopcock. Of course this loosened the gland and it slowly drip-dripped and he returned from work to a soaking kitchen carpet.

Been paranoid about it every since.

 

[Symptoms]

Been paranoid about it every since.

Best way to be with water, Pete.

 

[hi-spec plumbing heating]

Been paranoid about it every since.

people only get paranoid about it when they don't understand how the system works or how to deal with a problem.