CWSC in loft - advice

[rocketmanbkk]

Hi Friends

I got asked to view a job where the CWSC in the loft was leaking.

When I got up there in was immediately evident that there was a major leak as I could see a huge drip!

The CWSC, where the FOV enters had a stream of water running down the tank and the cold water feed compression joint (is this a tap connection fitting to the FOV?) was also loose.

Well, lucky for me I was with another person but as I was his 'boy' i missed what he did really (practically to view) as I was with the customer.

He said the FOV connection needed replacing and there was no isolation/service valve on the cold feed (15mm.

Now then, he had no new fittings so just made as good as he could with ptfe and silicon for the night.

He was going back today but I couldn't go.

So my questions on this is, if you turn off the cold water from the main (under sink) and then cut the 15mm pipe in the loft to fit the isolation/service valve, will water gush out when it's cut? I say no but as a newbie it's a massive confidence thing!

Also, when changing the FOV, do you use any silicone inside and outside the tank for the plastic nuts etc? What's the best way to make sure no leaks when it's put together? And lastly, is it a tap connector from the 15mm pipe to the FOV?

Hope all is well with you all.

Best regards

Rocket (trying to gain confidence!!)

 

[dontknowitall]

Not a stupid question! On my course a few years ago, I asked the same about cutting a pipe near the stop tap. After the "class" 3 others came up to me and said how relieved they were that I'd asked as they didn't have the guts!!

Anyway. If the water is turned off, apart from a dribble, not much water will come out. Most will stay in the pipe because water cannot travel uphill unless it's under pressure. Only proviso is that when you turn the stop tap off it's sensible before you cut into a pipe to open other taps to ensure the water has stopped as stop taps don't always work.

Better to use a service valve - similar to an isolation valve.

 

[rocketmanbkk]

Thanks Dontknowitall.

When i was younger I used to get embarassed to ask questiuons too, now, my hand will go up!

 

[SafeGasInstall]

when you turn water off but have not drain the water out ,if you cut into the pipe water will gush all over the place as it is under pressure ,however will not be for long unless stopcock is not been closed fully ,
so i sugest turn water off open kitchen sink tap run upstairs and push down the float valve if any water is coming out this means water is not off , and the tap under the sink is not closing the supply to the hall house ! Then go to the street and look for the main stopcock and repeat the above ,
if the main is not closing fully you can open kitchen sink tap and garden tap and go to loft and do the repair ,should any water still enter the house will be drain out from kitchen sink and garden tap wile you do repair in the loft ,cut in to pipe quick and stick new 15mm stopcock and turn the new stopcock off as they DO NOT COME FULLY CLOSED ,then run down and open all the supply and check for leaks ! if not sure do not try as could easily miss something and get the place full of water !

 

[PlumbBobBob]

when you turn off the stopcock open the kitchen cold tap then when you go up into the loft or wherever the pipe to cut is, open the fov by pushing down the ball arm so that the water in the pipe is released out of the kitchen tap. when you cut the pipe to put the valve in no water will escape.

 

[PlumbBobBob]

rats you beat me to it stan

 

[SafeGasInstall]

Sorry Stevie 🙂

 

[PlumbBobBob]

no probs stan good to see we're on the same wavelength lol

 

[stevetheplumber]

fov ? another acronym

 

[rocketmanbkk]

heres another question since you all sem to be having a well earned cuppa!

When you turn the main water off from the stop tap to drain the system, it is better to drain from the storage tank or just turn the downstarirs taps on? Also when refilling, is it practice to get up in the loft to make sure teh FPV is working and when the system is full it shuts off?

Everydays tips welcomed. (plumbing related only!)

 

[dontknowitall]

Not sure what you mean and, hoping not to make you sound an idiot (NOT my intention!!), I'm not sure you entirely understand the water works in a house.

Usually - but not always - the stop tap provides the entry of water to the house. A pipe will go to the kitchen sink to provide potable water. This pipe is also tee'd to go up to the loft to supply water to the cwsc. That is all there is to the stop tap supply.

The cwsc supplies the F&E cistern for the heating. It supplies the hot water cylinder. It supplies all other cold taps and wcs in the house.

So draining the storage tank is a totally separate issue from draining the pipe from the stop tap to the storage tank.

Hope this clears up some confusion.

 

[MRDrip]

The cwsc supplies the F&E cistern for the heating.

Now I'm a bit confused about how this works ?

 

[Howsie]

fov ? another acronym

Float Operated Valve.

 

[desrob]

if the gold fish bowl breaks you can put your fish there,only as a emergency though,return to newly purchased gold fish bowl.

 

[SafeGasInstall]

Float Operated Valve.

did not know this one

 

[stevetheplumber]

Now I'm a bit confused about how this works ?

youve lived up to your name there m8
(dontknowitall)

 

[dontknowitall]

Now I'm a bit confused about how this works ?

Perhaps because the heating's a sealed system?

 

[stevetheplumber]

did not know this one

me niether more college speak

 

[stevetheplumber]

with this thread in mind im wondering if we should have a few line diagrams as a sticky showing the three or four basic systems of heating , hot and cold water supply
maybe with a heading inviting posters to identifiy which system they have before posting

 

[dontknowitall]

youve lived up to your name there m8
(dontknowitall)

Oh, golly!!

Now I'm becoming confused!!!

In my house (and loads of others I go to) there are two cisterns in the loft. The main cwsc and the F&E cistern. Many times there is a feed from the cwcs to the f&E. This is a right pain when the F&E ball valve needs changing and does not have an isolation or gate valve because you have to drain the cwsc first.