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Post by fastflowfred on Nov 10, 2020 15:16:23 GMT
Hi guys can I please pick your brains ?
Long time, no plumbing here, so be gentle ...
I have to change the kitchen tap & so have to stop / drain the hot and cold feeds obviously.
It's an f&e system btw
Cold seems easy enough (stop cock off below the sink and there's a drain off just above to catch what's in the pipe above) ... I think / hope ; )
Hot though ... that's the current flexi that has failed and is leaking itself just after the compresssion joint on the pipework and thus initiating the whole job and decision to swap a tired / drippy tap ...
Do I have to:
1. drain down the whole hot water cylinder which means finding and turning off the gate valve that comes out the cws tank in the loft (so it doesn't continue to fill)? Or would it be better to fix the ball cock temporarily in the loft tank itself so it doesn't keep filling?
or
2. (I might be up a gum tree here but) is there some way to lock the three port valve off the cylinder so it doesn't drain or is that valve just to do with the CH? If so, and that's a goer, is that where you 'lock' the lever onto one of the three positions - I presume on 'CH' and is that A or B on the valve?
or
3. Is there ano / better way that doesn't require draining the hw cylinder plse?
n.b. I can't see / find any other isolation / lock / gate valve on what seems to be in / on any of the hw pipework either in the airing cupboard or under the sink.
Also
4. Am I correct in thinking that when i fit the new tap, the hw pipe needs a non-return valve in the pipework before each of the tap flexis please?
5. Neither the hot or cold pipework under the sink supplying the tap have isolation valves in line. Obviously, they would be better fitted for next time but am I correct in thinking that they need to be fitted for regs etc? And should they be in / on the pipework, not on the flexis themselves ?
Thanks in advance ; )
I can upload some shots if that helps.
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Post by DIYDafty on Nov 10, 2020 16:05:22 GMT
Right, I'm just a DIYer so I might well get some of this wrong so DO NOT act on my advice!
Firstly, if you isolate the HW cylinder by closeing a valve between the CW tank and itself you won't end up draining it. (To drain it you'd normally open drain off valve at the bottom of cylinder or pump the water out but I don't think you want to do any of that.)
Next, your 3 way valve is on the heating side and so not relevant to your work - forget about it for this job (IMO of course).
To isolate hot do what you suggest (valve on the feed from CW tank to HW cylinder) but if its a gate valve that has seized you might have to drain the CW through the cyliunder - wasting your hot water but not draining it out. You might be able to bung the CW tank if you havre bungs - I'm not sure about that. Look also for a valve on the output of the HW cyliunder.
If it was me I'd close any gate valves (from CW tank to cylinder or on output of cylinder) if I could to prevent the HW tank losing its HW water but either way I'd tie up the ball valve in the CW tank and open up all the taps until the water stopped coming through. Then replace.
As I said it could be all rubbish so wait for a kind plumber to come along....
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Post by crowsfoot on Nov 10, 2020 17:09:10 GMT
DDs not far of the mark Fred in what he say's.
I'd just turn off the mains water and run the hot taps until the water stops, you won't empty the cylinder just the cold water storage tank above.
You don't need any non return valves or even isolation valves on your system. although Iso's are handy for future maintenance.
Top tip is to totally empty the things out of the sink and get the shelf out if you can...It'll give yourself a bit of elbow room.
By all means feel free to upload a few photos of the job with those we can advise better and maybe spot a pitfall you need to avoid.
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Post by fastflowfred on Nov 10, 2020 23:00:33 GMT
Right, I'm just a DIYer so I might well get some of this wrong so DO NOT act on my advice! Firstly, if you isolate the HW cylinder by closeing a valve between the CW tank and itself you won't end up draining it. (To drain it you'd normally open drain off valve at the bottom of cylinder or pump the water out but I don't think you want to do any of that.) Next, your 3 way valve is on the heating side and so not relevant to your work - forget about it for this job (IMO of course). To isolate hot do what you suggest (valve on the feed from CW tank to HW cylinder) but if its a gate valve that has seized you might have to drain the CW through the cyliunder - wasting your hot water but not draining it out. You might be able to bung the CW tank if you havre bungs - I'm not sure about that. Look also for a valve on the output of the HW cyliunder. If it was me I'd close any gate valves (from CW tank to cylinder or on output of cylinder) if I could to prevent the HW tank losing its HW water but either way I'd tie up the ball valve in the CW tank and open up all the taps until the water stopped coming through. Then replace. As I said it could be all rubbish so wait for a kind plumber to come along.... Thanks Dafty, appreciate that. What was i thinking about the 3 port valve? Blimey :0 OK, so was sort of on the right lines ... I have found a gate valve off the cw cistern dropping to the base of the cylinder, with an additional run to the front of the cupboard and a drain cock at the end. I guess that must be 'it' and i need to close that. You mention it seizing but how do you know? Do they just refuse to budge? And can they be 'persuaded' with a little brute force and / or WD40 perhaps? Ideally, i could 'bung' (can you get such things?) the cw cistern and it would do the same thing? Failing that, and second best, are you saying tie off the ball cock in the cw cistern so that even if the gate valve / bung (if i can get one) doesn't work, then opening the taps will 'only' drain that tankful? (I say only as it will in fact drain x2 tankfuls as I put in ano 25g cistern to run the power shower - which makes me think i really should have put a isolator on it back then, but hey ho.) * goes off to google 'bungs' * - could be interesting ?  Thanks again. |
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Post by fastflowfred on Nov 10, 2020 23:22:56 GMT
DDs not far of the mark Fred in what he say's. I'd just turn off the mains water and run the hot taps until the water stops, you won't empty the cylinder just the cold water storage tank above. You don't need any non return valves or even isolation valves on your system. although Iso's are handy for future maintenance. Top tip is to totally empty the things out of the sink and get the shelf out if you can...It'll give yourself a bit of elbow room. By all means feel free to upload a few photos of the job with those we can advise better and maybe spot a pitfall you need to avoid. Thanks also crowsfoot , reading your reply, I realsie that, turning off the main stop cock (which I'll do anyway) is the same as tieing up the ball cock in the cw cistern, right? But am I right in thinking that this empties the remaining cylinder hot water and all the cw cistern water ? Sorry, I don't quite get what ypu mean when you say: " it won't empty the cylinder, just the cw storage tank above " ? Slightly confused, but how can it not empty the cylinder also as the water in the cw storage tank(s - see post above) has to pass through the cylinder, doesn't it to drain? Yes "iso's" will come in handy no doubt in the future, so I'll put them on. I was convinced i read / saw that a one way / non-return valve on the hot was recommended while I'm at it, to stop any water going back up the pipe into the cylinder, then the cw tank and overflowing (if the tap was ever faulty)? Obviously not. After much wrestling, I got the shelf out and my elbows will now be everywhere, thanks. Might take the traps off too - will see. Any advice on bungs (!) and stuck gate valves might come in handy also... Will just have a play to see if i can get the photos off the phone for reference of the under the sink bit & post if so... |
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Post by cylinderfella on Nov 10, 2020 23:23:25 GMT
The guys above are right. Also, watch out for the gate valve (one of the worst inventions), when it's closed fully the water might keep running as gate valves don't close properly after many years. Rip it out and swap for a full bore lever valve if there's space. Turn off the mains and turn on hot a cold at the tap to drain out both supplies just to do the kitchen tap though. If you can isolate the hot supply from the cylinder you'll save a load of water and time.  |
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Post by fastflowfred on Nov 10, 2020 23:26:18 GMT
 Ah, that didn't work ... |
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Post by fastflowfred on Nov 10, 2020 23:38:31 GMT
The guys above are right. Also, watch out for the gate valve (one of the worst inventions), when it's closed fully the water might keep running as gate valves don't close properly after many years. Rip it out and swap for a full bore lever valve if there's space. Turn off the mains and turn on hot a cold at the tap to drain out both supplies just to do the kitchen tap though. If you can isolate the hot supply from the cylinder you'll save a load of water and time. Thanks. I'm fearing the worst now on the gate valve  As above, I think I'll know if it's seized solid but how will I know if it's not closing fully - will I just shut off the cw at the mains and wait and wait and wait ... and if the taps are still dripping (or ot empties the cw cistern?) then it's busted? Can they be 'persuaded' to work generally or does it just break them? And if so, I guess it's a job (a new / replacement lever valve*) that I might as well do while it's all empty? * would that be a blue lever or a red one strictly speaking btw please? I'd love to isolate the cylinder but can't see an iso or shut off valve anywhere to hand - anywhere else to look please? (As mentioned above about the twin cw tanks, that's a lot of water I could do with not wasting ideally.) Thanks. |
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Post by crowsfoot on Nov 11, 2020 7:17:42 GMT
Hi Fred, The word is "displacement", which is how the top cold water storage tank empties the storage cylinder's hot water yet remains full.
Good that you've given yourself some extra room and yes taking the sink trap off is fairly easy and will give you some more much needed room.
Emptying the storage tanks will waste a lot of water, however, this is the least of the evils that can be involved when you start turning old gate valves.
There's quite a lot of restriction in isolation valves and on a gravity system like yours it may reduce the new taps hot water flow to a trickle so make sure it's a full bore isolation valve if you are going to fit one.
An airlock could be the only problem you may get with fully draining down the CWST and refilling it.
Good luck.
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Post by battle1066 on Nov 11, 2020 8:47:12 GMT
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Post by battle1066 on Nov 11, 2020 8:58:30 GMT
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Post by tomplum on Nov 11, 2020 9:54:42 GMT
Hello fastflowfred, Welcome to he brewcabin, All of the advice given up to now is correct and I hope it helps you, When you finally get the pipes empty of water putting ballofix isolating valves is good for next time because, todays modern taps will not last as long as the old ones, www.toolstation.com/isolating-valve-cp/p36879edit, whoops sorry Battle, I see you already advised valves as well, yes the ones with handles are better but, more expensive, I'm a tightwad me,,,  and don't be afraid to use push fit, they work good and much easier to use for DIYers.  |
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Post by fastflowfred on Nov 11, 2020 11:53:00 GMT
Thanks. So, if I bung the cwst in the loft, can I just turn on the hot tap (any?) to drain any excess, and will that essentially stop any 'flow' - allowing me to work kn downstairs? I take it they just insert, and screw in making the seal? And should that way, give me the best chance of avoiding any airlock subsequently? |
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Post by fastflowfred on Nov 11, 2020 12:00:54 GMT
Hi Fred, The word is "displacement", which is how the top cold water storage tank empties the storage cylinder's hot water yet remains full. Good that you've given yourself some extra room and yes taking the sink trap off is fairly easy and will give you some more much needed room. Emptying the storage tanks will waste a lot of water, however, this is the least of the evils that can be involved when you start turning old gate valves. There's quite a lot of restriction in isolation valves and on a gravity system like yours it may reduce the new taps hot water flow to a trickle so make sure it's a full bore isolation valve if you are going to fit one. An airlock could be the only problem you may get with fully draining down the CWST and refilling it. Good luck. Thanks again. I might try the bung route ... hopefully saving water and avoiding airlock(s). Take the flowrate point & so will also look at full bore iso's as recommended ... Not sure the ones linked by Tom are the full bores (?) but think these are: www.toolstation.com/full-bore-isolating-valve-cp/p11495That way, I can also avoid the swap out of the gate valve to a lever as recommended above (if needed). Are they a 'straight swap' btw, i.e. in terms of height to fit in the (same) space vacated by the gate valve - not sure I'm quite up to soldering in new sections at the back of the airing cupboard yet : ( |
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Post by fastflowfred on Nov 11, 2020 12:08:42 GMT
As per my reply to crowsfoot , do you know of these are a striaght swap with the gate valve (I think i have a pretty standard one) vis a vis height within the pipework? I guess if the lever valves are larger, it is OK - I can trim the pipe - but if they are smaller, I'd be worried to be trying to patch in (soldering) a new pipe section at the back of the airing cupboard. |
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