Jumpy Guy
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| posted on 31/3/07 at 08:07 PM |
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Any plumbers in the house - query!!
i have a water storage tank in my airing cupboard, with an immersion heater..
the imersion heater has stopped working, so i have a new one, ready to fit.
midway through loosening the old immersion heater at the top of the tanks, it suddley occured to me- is this tank pressurised?
do i need to turn the mains water off before i continue?
theres an incoming pipe with a tap feedining the tank, should i turn this off?
drain tank?
or, can i just loosen and take out the old heater element??
any answers appreciated before i flood the house!!
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BenB
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| posted on 31/3/07 at 08:13 PM |
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Some tanks are pressurised, some aren't....
The easy way of finding out is to isolate the tank by spinning the stopcock going into the tank, run it a bit to drain it below the element level
then take out the element. If it begins to leak lots of water it's pressurised....
Even the pressurised ones aren't that pressurised (ie the element isn't going to blow out of your hands as you unscrew it)...
If it begins to hose you just screw it back in and unpressurise it a bit more by draining.... If it's pressurised then you might need to
re-pressurise it afterwards.
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Jumpy Guy
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| posted on 31/3/07 at 08:27 PM |
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hmmm . ok - i have four pipes into the tank-
one striaght into the top, which has no tap
one which goes into the bottom, which has a tap
and two next to the middle of the tank, one of which has a tap
what do these all do ???
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mistergrumpy
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| posted on 31/3/07 at 08:46 PM |
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Pipe on the top is outlet for your hot water, pipe in bottom is inlet for your hot water. T'other two are connected to each other by a spiral
pipe called a sidewinder. Your central heating water runs through this pipe and this then warms the water in the rest of the cylinder or t'other
way round i.e. the water warms the spiral, but anyhow, thats it. May be best to just turn your mains off, run the hot water till its below the
immersion heater level, replace it then turn mains back on and cylinder will fill itself back up.
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Neil P
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| posted on 31/3/07 at 08:58 PM |
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Step away from the tools!
The cylinder is fed from a cold water storage tank in your loft. If the cold water feed ( the single pipe to the bottom of the tank) has a valve on
it, then shut it off. This will stop any fresh water entering the cylinder. Open your hot water taps to drain off whats left in them. Your cylinder
will still be full of water, opening the taps will only drain down to the top cylinder connector. If there is no drain off on the cylinder then you
will need to undo the top connector, stick in a hose pipe and syphon the water out until it is below the level of the immersion heater. It's a
good idea just to break the seal on the immersion prior to draining off as the water pressure helps to stop the cylinder deforming if the immersion is
tight.
Good luck
Neil
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Jumpy Guy
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| posted on 31/3/07 at 09:14 PM |
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gets even more interesting!!
the reason im changing the imersion is that its our only source of hor water- our central heating boiler doesnt heat the water.. been like this since
iu bought the house 18 months ago...
but mistergrumpy says the two pipes in the middle of the tank are connected to my central heating system.... so...
does that mean my central heating is connetected to the tank, but not working??
btw.. ive given up on changing the immersion heater- the first burst of water convinced me it was pressurised!!
[Edited on 31/3/07 by Jumpy Guy]
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JoelP
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| posted on 31/3/07 at 09:31 PM |
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i would guess that your rads are being heated from the immersion heater, via the two pipes in the side. Whenever i get stuck on plumbing like this i
ring my pal whos a full timer.
Does that mean you have no hot water at all now?! Time for an upgrade methinks!
[Edited on 31/3/07 by JoelP]
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Jumpy Guy
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| posted on 31/3/07 at 09:56 PM |
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thanks for that!!
situation now- no imersion heater = no hot water!!
central heat still working though Joel...
hmmm.. call a plumber on monday, i think!!
anyone recommmend one in Marlow/wycombe/windsor/Reading area?
[Edited on 31/3/07 by Jumpy Guy]
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MikeRJ
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| posted on 31/3/07 at 09:58 PM |
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quote:
Originally posted by Jumpy Guy
but mistergrumpy says the two pipes in the middle of the tank are connected to my central heating system.... so...
does that mean my central heating is connetected to the tank, but not working??
Normaly this would be connected to your boiler via a 3 port motorised valve ( e.g. like
these). This either directs water flow from the boiler through
the radiators in the house or the heat exchanger inside your tank.
Does the tank have a thermostat strapped to the side of it? It's fairly common for the 3 port valve to stop working due to getting silted up
etc. so it could just be stuck to the radiator position.
[Edited on 31/3/07 by MikeRJ]
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Jumpy Guy
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| posted on 31/3/07 at 10:07 PM |
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havent seen one of the motorised valves - would it normally be next to the tank in the airing cupboard, or in the attic?
the immersion heater has a built in thermsostat.
interestingly, our central heater boiler controller has a timer for hot water, which has never worked since we got here....
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nitram38
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| posted on 31/3/07 at 10:11 PM |
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Are you sure it is the immersion heater that is at fault?
There is a pull out thermostat that controls the immersion element. These can be faulty and also can be replaced without draining down. They are in a
sleeve.
It is normally under the immersion cap and looks like a block with wires and a small adjuster so that you can set your own temp.
You can use a continuity test to see if it is a closed circuit when cold.
Pity you don't live nearer.
I am an Electrician and I get to change immersion elements sometimes. I even have the proper spanner in my car.
The immersion is in the hot water side of the tank so you must stop the feed into it, plus drain it down.
It is not that difficult.
Here is a pic of the thermostat being pulled out:
Here is a link of how to do it
[Edited on 31/3/2007 by nitram38]
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Blackbird Rush
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| posted on 31/3/07 at 10:35 PM |
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quote:
Originally posted by Jumpy Guy
anyone recommmend one in Marlow/wycombe/windsor/Reading area?
[Edited on 31/3/07 by Jumpy Guy]
Yup....U2U sent
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Peteff
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| posted on 31/3/07 at 10:43 PM |
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does that mean my central heating is connetected to the tank, but not working??
If it's a gravity system the two pipes feeding into the tank may have an airlock. Crack the joint on the top one and let it flow a bit of water
then tighten it back up, it has a red fibre washer so don't overdo it. It should have a breather pipe going up from it to the header tank in the
loft.
Simplistic diagram
 
Rescued attachment tank.jpg
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Jumpy Guy
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| posted on 1/4/07 at 10:11 AM |
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thanks for hte diagram pete, but i have one question-
you say open the top valve and let it flow water, but isnt it meant to flow water from the central heating all the time? isnt that how its meant to
heat the water( which admittedly doesnt work)
bear in mind i know NOWT about plumbing...
cheers
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Peteff
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| posted on 1/4/07 at 11:48 AM |
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It is supposed to heat by convection, the pipe going straight up is a vent pipe to vent air in the system and will be bent over at the top above your
heating header tank in the loft. Another way to do it would be to get into the loft, stick the end of the vent pipe in your mouth and suck. The water
will rise then find its own level again.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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MikeRJ
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| posted on 1/4/07 at 12:40 PM |
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quote:
Originally posted by Peteff
It is supposed to heat by convection,
We had the remants of an old back boiler in our fireplace whch heated the hot water tank directly using thermosyphon, but it had huge great pipes.
I'm not a plumber but I'd have thought a gas or oil driven boiler would require a pump to get enough flow? Perhaps not.
Mr Jumpy, the 3 port vale is often next to the tank, but could also be placed nearer to the boiler, and some boilers have the valve built in so you
might still have one.
Usually you would have a thermostat strapped around the tank to switch the boiler on when water temperature falls, but I have seen systems installed
without them that just heats the water for a pre-set time per day and relies on the thermostat in the boiler.
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Peteff
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| posted on 1/4/07 at 02:06 PM |
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Ours is pumped heating, gravity hot water. It's an old system but is still efficient so I'm working on the principle that if it's
not broke, don't replace it. It uses 22mm pipe to the coil in the hot water tank and heats it to the temperature set on the boiler thermostat.
Even when the pump is not on the upstairs radiators get warm so don't underestimate the power of convection.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Jumpy Guy
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| posted on 1/4/07 at 03:14 PM |
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some further investigation-
there doesnt seem to be amy thermostat on the tank, except the one on the imersion heater....
neither of the middle pipes on the tank ever get hot, even when the central heating is on.
so, does that mean that the three port valve never switches over to this loop?
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