Can I use 1/4 turn ball valves in place of gate valves for my CH/HW system. My previous experiences with gate valves suggest that seepage past (when in the closed position) is a problem. I would like to be able to turn-off the feeds to each bathroom for hot and cold water. Ball valves look quicker to use, but I don't know if there is any reason I should avoid them for this purpose.
Fash
I've used full bore ball valves all over the place in our CH. I think they're great. It's really handy to be able to isolate bits of the system, without any loss of flow.
They are ideal for this. Last time I did some work on my heating and HW systems, all the gate valves were consigned to the skip and replaced with lever ball valves.
Also, they are a good solution as isolating valves for taps where you need full bore flow.
.andy
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Can they also be used as a mains stop c*ck?
Yes. Use 1/4 turn full bore lever valves for everything, except for isolating low flow appliances such as washing machines and basin taps, which can use cheap reduced bore isolating valves.
Christian.
One more question, do motorized valves produce a full shut off, such that if I use a motorized zone valve on the flow and a ball valve on the return I can isolate a section of the CH circuit?
Fash
They do a reasonably good shut off but not enough to act as an isolation if you want to do plumbing work.
.andy
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I wouldn't rely on it. However, the brand I used appeared to be as good as a gate valve in shutoff, when I blew down one end. I would definitely fit specific isolating valves if I needed such isolation, though.
Christian.
For a stop c*ck make sure it is a good quality stainless steel valve.
Water companies are now fitting them as standard, or a charge as a retrofit. The quality has to be good, hence the stainless valves.
I did believe it.
I don't know about full bore valves but I've come across seized iso valves due to a build up of scale and would recomend giving them a turn every now and then to keep them free.
Dave
The main reason for not using a ball valve in a circuit is that shutting a flow off quickly can produce water hammer. Isolator valves are normally only used when there is little or no flow, so it is not a problem for that application. Depending on the circuit layout, it may or may not be a problem when used to cut off circuits that could be carrying a flow. The answer is probably to try a ball valve and, if it produces water hammer, replace it with something that closes slowly, like a gate valve.
Colin Bignell
On Thu, 6 May 2004 00:15:32 +0100, in uk.d-i-y "nightjar" strung together this:
Or, close the valve slowly.
That is not an acceptable solution, even if it is possible to close a quarter-turn valve slowly enough. It is a basic principle that one day either you will forget or someone else will operate the valve, which could blow a pipe fitting off somewhere.
Colin Bignell
What, the water companies are fitting motorised CH valves as stopcocks?
Christian.
On Thu, 6 May 2004 08:13:17 +0100, in uk.d-i-y "nightjar" strung together this:
Fairynuff, just a thought. I manage it but not everyone has to.
Can't really see water hammer being a problem in a CH circuit, as I would be unlikely to want to turn off a zone if there was a demand on it at the time, so when you operate them in this application there should be no flow, and anyway the pressure on a CH flow is not very high is it?
Fash
That is why I suggested a suck it and see approach after making the point originally. However, in other applications, it can happen and then I would want to have a solution that relied upon the equipment design, rather than on operating procedures. Procedures as the only way of avoiding problems is always the last and least desirable option for any safety system.
Colin Bignell
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