# New hot water cylinder?



## aircobra19 (18 Aug 2008)

What sort of cost is involved in fitting a new hot water cylinder. I've heard theres a new type (pressurised) and then old type. Whats the difference.


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## blade39 (19 Aug 2008)

Im in the same boat just got a quote of several hundred plus labour. There is a tiny leak at screw but plumber says that its factory fitted and whole tank needs taken apart. I thought simple solder but you cant solder these tanks or use plumbers tape.


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## DavyJones (19 Aug 2008)

standard cylinder is 30" high and 18" wide, it costs about €150,immersion €40, fittings/pipe approx €30. labour €250 (it takes a few hours and some may charge for the day, others on percentage of day) plus 13.5%. 

A pressurised cylinder is one that is under pressure by means of mains or storage tank via pump that pumps through cylinder (giving high pressure hot water at outlet), the cold water would be of equal pressure as they would both be fed from same source I.E mains or pump. This cylinders have to be made from stainless steel or similar to cope with stress. These cylinders are expensive, they last much longer, if fed off mains than no need for storage tank in attic.

An unpressurised cylinder is what most people have (copper). the cylinder is only under the pressure that is excerted by the height of the storage tank in relation to the cylinder (higher thwe storage tank= greater the pressure). However a pump can always be fitted after the copper cylinder to pressurise plumbing system I.E the pump pulls water from the cylinder as opposed to forcing water through it.


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## ClubMan (19 Aug 2008)

My mother had her old water tank/immersion replaced with a factory lagged one, some of the piping plumbing this into the water and _OFCH _systems replaced/redone, and the attic tank replaced with a new plastic one for €500 recently.


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## aircobra19 (19 Aug 2008)

That seems a good price Clubman. I'm getting quotes of between 650, 800. Though I am getting some pipes moved around to create more space in the hotpress.


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## aircobra19 (19 Aug 2008)

DavyJones said:


> ... cylinders are expensive, they last much longer, if fed off mains than no need for storage tank in attic....


 
Why no storage tank?


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## ClubMan (19 Aug 2008)

aircobra19 said:


> That seems a good price Clubman. I'm getting quotes of between 650, 800. Though I am getting some pipes moved around to create more space in the hotpress.


He originally quoted about €650 but when he (eventually - long time later and only after she chased *HIM*!) returned to get paid she haggled a bit and he knocked the price down.


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## Towger (19 Aug 2008)

aircobra19 said:


> Why no storage tank?


 
In most other countries their mains supply is at a much higher pressure than here. So no need for a tank in the attic.


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## aircobra19 (19 Aug 2008)

In those other countries or in Ireland?


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## Towger (19 Aug 2008)

aircobra19 said:


> In those other countries or in Ireland?


 
Most other countries don't have tanks in the attic, as standard, in houses.
Most countries = Those which were not part of the British Empire!


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## aircobra19 (19 Aug 2008)

Maybe I'm not asking the right question.

I mean, why in Ireland do you not need a storage tank for that type of pressurised cylinder.


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## davidoco (19 Aug 2008)

aircobra19 said:


> Maybe I'm not asking the right question.
> 
> I mean, why in Ireland do you not need a storage tank for that type of pressurised cylinder.


 
Because the water pressure coming into the house from the public mains (easily checked at your cold tap in the kitchen) is too low to provide the pressure for the hot water cylinder. 

Some folks (I'd say <10% of pop) live in a area with high pressure or if you have your own well you can use the well pump to deliver higher pressure.

Remember also that your storage tank provides some backup in the event of the water being cut off in your area for flushing toilets etc for a day or so.

Good diagrams here [broken link removed]


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## ClubMan (19 Aug 2008)

davidoco said:


> Because the water pressure coming into the house from the public mains (easily checked at your cold tap in the kitchen) is too low to provide the pressure for the hot water cylinder.


In which case they presumably *WILL *need a water tank!?


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## aircobra19 (19 Aug 2008)

Reading between the lines...

Perhaps it should read, May not need a storage tank IF you have high pressure water supply. As some areas in Ireland have high pressure mains and some from a well pump. Most have a low pressure and need a tank. 

I ask because it would seem like a good way of reclaiming some attic space. If you consider it going to cost 500-700 just to fit the same old cylinder vs 2500 ish to replace the lot with a new pressurised system. Does the rest of the system, bolier, toliets, rads need to be changed for a high pressure system?


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## Towger (19 Aug 2008)

Was I that unclear?

Another question: Assuming your mains pressure is low (as is most of Ireland). Is is kosher to use a Tank in the Attic and a Pump to supply high pressure water (22/28mm pipes) to a Combi Boiler (assuming small house, one bathroom etc). Thus doing away with hot water cylinder. From memory, instructions for Combi Boilers want mains only supply. 

AirCobra. You still need a tank as to supply the pump, as AFAIK it is illegal to connect a pump to the mains supply.


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## aircobra19 (19 Aug 2008)

Towger said:


> ...AirCobra. You still need a tank as to supply the pump, as AFAIK it is illegal to connect a pump to the mains supply.


 
If you always need a tank, the what was all that about not needing a tank. Or is it illegal in Ireland, and not elsewhere, or just that you only need a pump in Ireland.


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## Towger (19 Aug 2008)

To put is simply (there will be exceptions), you only need a pump (+ tank) in Ireland/UK, for high pressure water. In most other (European) countries the mains pressure (no tank) is much higher. This is why people have problems when they buy cheap (non rip-off) taps etc in France and Germany. They connect them up here and then complain they dont have enough water coming through them. Of course not, they are designed to reduce the pressure, so turning on the tap does not result in water bouncing off the bottom of the sink into your face.


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## aircobra19 (19 Aug 2008)

aircobra19 said:


> ....Does the rest of the system, bolier, toliets, rads need to be changed for a high pressure system?


 
So Yes I guess is the answer.


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## Towger (19 Aug 2008)

It would only effect the taps/toliets, you can reduce the pressure to them easly enough. Unless you went for the 'Combi' option, I asked about. This is where your central heating boiler would also heat the hot water 'on demand', so no cylinder. These require a higher incoming water pressure than most Irish mains supply.


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## DavyJones (19 Aug 2008)

aircobra19 said:


> Reading between the lines...
> 
> Perhaps it should read, May not need a storage tank IF you have high pressure water supply. As some areas in Ireland have high pressure mains and some from a well pump. Most have a low pressure and need a tank.
> 
> I ask because it would seem like a good way of reclaiming some attic space. If you consider it going to cost 500-700 just to fit the same old cylinder vs 2500 ish to replace the lot with a new pressurised system. Does the rest of the system, bolier, toliets, rads need to be changed for a high pressure system?



Whe you think of your home plumbing, it is really two seperate systems I.E plumbing system(hot/cold water) and the heating system. These two systems don't mix but come into connect in the cylinder .I.E the heating water from boiler heats the plumbing hot water indirectly.

to answer your question, you don't need to pressurise heating system if you have a pressurised plumbing system, however if you want to remove all tanks from the attic making the heating system a sealed type will acheive this.

The tank that feds the heating system is the small one.


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## aircobra19 (19 Aug 2008)

Ok thanks, I'm getting the idea now. In terms of pressure some boilers need a certain amount of water pressure to run. Its that because you need to have a certain flow rate of water through the boiler? How often should a closed system need topping up and do you do it when the boiler is running? (While you can read the pressure gauge on the boiler?) I have a manual valve to put water into the heating system.


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## DavyJones (19 Aug 2008)

You have a sealed system. no small tank in attic. Best to read gauge when system is cold as water increases in volume (it expands) when hot. For example if your system is set at 1bar it will increase to 1.5bar when hot and return to 1bar as it cools. You should only top it up once in a blue moon. If you do it a lot, it can mean a leak or a problem with the expansion vessel.


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## aircobra19 (19 Aug 2008)

Whats once in a blue moon, once a year, once every 5 years?


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## DavyJones (19 Aug 2008)

Once a year would be acceptable. How often do you do it?


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## aircobra19 (19 Aug 2008)

I've only done it once about 2 yrs ago. Had someone in sorting out other problems and he noticed the pressure was low. Then realised there was no way of getting any water into the system by the original plumber (house bought from new), so a valve etc for that was added. Need to do it again, now. It was suggested to put an automatic valve on it.  I didn't think it was needed. I generally look at the pressure from time to time anyway. There maybe a small leak in the system. I haven't tracked it down yet.


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## DavyJones (19 Aug 2008)

That is very strange as presumably the first plumber filled the system with water first day. I have found filling loops/Automatic filling valves in very unusual places. Attic, behind cupboards that were not there when system installed etc.

I,m with you on thinking an AFV is unnessary, they canmask leaks . By the sounds of it your system is ok. If there was a small leak, your gauge would have dropped to zero  after time certainly months. If you suspect a small leak now, check any works that have been done recently like the filling loop.


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## aircobra19 (20 Aug 2008)

I know theres one rad weeping a tiny bit. There was another leak which I need to lift a floor board to access, but it seems to stop on its own. Nothing the original plumber has done would surprise me. He was useless.


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## Towger (20 Aug 2008)

The previous owner of my house was and still is a plumber. Some of the bodges in it make me shudder. There is a structural beam upstairs which was cut half way through to install central heating. I spotted it when I had a look under the floor boards, it is now categorised as 'out of site, out of mind'. It holds up the bathroom and back bedroom floors. Problem is, the wife wants the bathroom tiled, but I dont want the additional weight on it! The filling loop is hidden under the floor boards, under the stairs. The hot water cylinder is down stairs (was back boiler), first in the circuit and there _was_ no valve to the coil in it! So I could not balance the system. This meant that two radiators would not heat, in an extension he added. He even made attempts to fix this! I added a valve to the feed to the cylinder, closed it half way and hay presto. Hot radiators. My fix also allowed me to stop the upstairs radiators heating, then the central heating was off and the immersion was set to bath! The system leaked in 3 places (that I know of). One is a Blank from him moving a radiator. I went to tighten it and a half turn later. Sh*t the blank and olive came off the (22mm copper) pipe, along with half the water in the system. The second leek is at an other junction were the pipe does through a wall, so I cant get at it. The third is a faulty stop cock at the pump, I have had a new one for the last two years, but yet to install it. To top it all off, when he moved a couple of the radiators he used standard plastic cold water pipe.


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## DavyJones (20 Aug 2008)

aircobra19 said:


> I know theres one rad weeping a tiny bit. There was another leak which I need to lift a floor board to access, but it seems to stop on its own. Nothing the original plumber has done would surprise me. He was useless.




Best to tighten fitting under the floor, as i said earlier, when water heats it expands. this expansion can seal small leaks but they may return when volume decreases.


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