Water from a vent pipe
- Thread starter Teggs
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Softus said:
Rubbish
The water will be pressurised by the mains and take the least line of resistance.
The vent if you hadn't noticed is connected to the hot pipe at the top of the cylinder, the mains water will therefore bypass the cylinder and cold feed and go straight up the vent.
if the OP turns the mains water off when its overflowing he will notice it stops, prooving my point.
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Hm, well, let me see, how can I put this, hm. You're wrong.doitall said:
In the view of the fact that this is a useful illustration of the point about which you're utterly wrong, sarcastic is a particularly inadvisable thing for you to be at this juncture.
Will it indeed? Will it actually stop doitall? Or, by virtue of your new theory of pressure (the one that redefines the laws of physics), will it instead "take the least line of resistance", and flow from the cistern, through the DHW cylinder, and back up the vent.
If you'd been somewhat more tolerant towards me when you believed that I'd made a mistake, which, BTW, I hadn't, I'd feel a tad more benevolent towards you doitall. Inetad, I'm beside myself with excitement knowing that one day the realisation will hit you that you're utterly wrong. And the longer it takes you to realise it, the harder it will hit.
Or am I wrong? Have you discovered a useful new form of perpetual motion?
Cheers guys,
I hope I haven't caused an argument.
As it happens I've just had a new shower room fitted, I was wondering if this was related (sorry I should have mentioned it before). This consists of a shower mixer valve and also a basin mixer tap.
While I have seen water come from the vent pipe I could not necessarily say that it was enough to fill the tank to the level of the overflow.
I have noticed that the water in the cold water storage tank is warm if that helps you in any way.
Terry
I hope I haven't caused an argument.
As it happens I've just had a new shower room fitted, I was wondering if this was related (sorry I should have mentioned it before). This consists of a shower mixer valve and also a basin mixer tap.
While I have seen water come from the vent pipe I could not necessarily say that it was enough to fill the tank to the level of the overflow.
I have noticed that the water in the cold water storage tank is warm if that helps you in any way.
Terry
Softus isn't right. when the water is running out the vent, turn the mains water off, it will stop, you then need to find out what fittings have a mains cold, check the new shower first.
in the picture if the valve is faulty and letting by the mains water will travel back up the hot pipe and over the vent
in the picture if the valve is faulty and letting by the mains water will travel back up the hot pipe and over the vent
hey, doitall. I have a feeling I shouldn't get into one of Softus' arguments, but... you've missed out the cold supply from the cistern to the cylinder.
Because this is lower than the vent pipe, if you think of the water trying to get out of the cylinder and back to the cistern, it will have to rise less high one way than the other.
As you say, it will take the line of least resistance, and will rise up the pipe that goes less high.
Otherwise the water level in the vent pipe would be higher than the water level in the cistern... which doesn't make sense
Because this is lower than the vent pipe, if you think of the water trying to get out of the cylinder and back to the cistern, it will have to rise less high one way than the other.
As you say, it will take the line of least resistance, and will rise up the pipe that goes less high.
Otherwise the water level in the vent pipe would be higher than the water level in the cistern... which doesn't make sense
Teggs said:
We like arguments, later we all take sides and call each other names
Back to the problem, is the new basin taps connected to the mains water.
If so when the vent overflows turn the isolating valve off. You may be able to simulate the problem by opening and closing the tap, ( tap open vent runs, tap off vent ok).
It helps a lot actually - there is no doubt now.Teggs said:
Mains water is passing from cold to hot supplies within a mixer valve in your house - this is likely to be a shower valve (not a kitchen or bath mixer) because of the way they work.
The test for the theory, as doitall correctly pointed out, is to shut off the cold mains to the house while the overflowing problems is happening, then verify that the overflowing has stopped.
Water, however, isn't passing from the vent. I'll put any money on this being condensation from the heated water in the cold storage cistern. If you have a lid on it then the underside of this will also be abnormally wet.
The problem is caused by the incorrect installation of a shower valve with unbalanced supplies. Whilst the shower valve might well be faulty, too much is being asked of it, and you need to fit a pressure balancing valve to any and all showers that are being fed with unbalanced supplies.
The only other options are (a) fit an isolating valve to the shower cold supply, and turn it off after every shower, or (b) convert the whole house to pressured hot water. Maybe someone else can think of some more options.
JohnD said:hey, doitall. I have a feeling I shouldn't get into one of Softus' arguments, but... you've missed out the cold supply from the cistern to the cylinder.
Because this is lower than the vent pipe, if you think of the water trying to get out of the cylinder and back to the cistern, it will have to rise less high one way than the other.
As you say, it will take the line of least resistance, and will rise up the pipe that goes less high.
Otherwise the water level in the vent pipe would be higher than the water level in the cistern... which doesn't make sense
John D.
Softus is wrong, perhaps I'm not explaining this very well
The cold feed or the cylinder has nothing to do with the problem.
Mains pressure is backing up the hot pipe as a result of a faulty fitting
The only reason I rubbed it in, on this occasion, was that this innocouous comment:gasmanuk said:
was followed by these little gems:
Rubbish
As I said earlier, I'm easily capable of being wrong myself, and would have had no problem with doitall being wrong (about water coming from the vent) if he'd just been straightforward and courteous about it. I agreed with him entirely on the accumulator topic, but for some reason he's decided that I'm not a plumber, and has decided to be particularly unpleasant about telling me that I'm not, so he deserves everything that comes his way.
So, moving on, we still have this little problem:
You're explaining it very well actually, it's just that you're wrong.The berk said:
I've love to hear your theory about why the CSS has warm water in it then!
This is the part that you're right about:
Quite so - I never disputed that, but it isn't coming out of the vent!
Mains water is reaching the DHW cylinder (at the top, i.e. the hot outlet), displacing the hot water within, and forcing it back up the cold feed (from the base of the cylinder) into the CSS.
For anyone who's still wondering why it does that, it's all down to pressure - the head of water in the vent is the same as that of in the cistern, so the water level will rise in both. It won't come out of the vent simply because it overflows from the cistern first.
The reason I didn't suggest check valves is that I've tried doing that before, twice, and it didn't work. Check valves are quite good at stopping syphoning at small of even vast rates, but it seems that the ones I buy couldn't stop a relatively small trickle at the difference between mains and tank pressure.doitall said:
However, doitall has suggested a valid thing, and it would be a very cheap solution it if worked.
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