Cylinder size

whitelightrider · 17-03-2008 6:58pm #1

Right guys quick question. Just speaking to the plumber and he is installing a 300 litre cyclinder. I mentioned the 500 litre but he said it was overkill. Should I push for the 500 litre or is the 300 litre ok for a 2200 sq ft house?

CJhaughey · 17-03-2008 7:03pm

How many occupants? how many in a few years?

I would go with 400l as a middle ground, are you fitting solar at any point in the future? would it be worthwhile to fit a dual coil cylinder?

whitelightrider · 17-03-2008 7:19pm

CJhaughey wrote: »

How many occupants? how many in a few years?

I would go with 400l as a middle ground, are you fitting solar at any point in the future? would it be worthwhile to fit a dual coil cylinder?

Id say at most there would be 5 in the house eventually. We are looking at fitting solar panels straight away so either a dual or triple coil cylinder might be needed.

AckwelFoley · 17-03-2008 7:22pm

whitelightrider wrote: »

Id say at most there would be 5 in the house eventually. We are looking at fitting solar panels straight away so either a dual or triple coil cylinder might be needed.

Sei suggest 50L per occupant.

300 is plenty imo.I would strongly advise getting a triple coil, Its invaluable to have a spare coil in any event of a future heating source.

If there is the oppertunity, some cyls have the capicity for dual immersion, id add that too.

A triple coil will set u back about 1600 euro and a dual anything in and around 1100, but ts worth it paying the extra few euro. Shop around

De_man · 18-03-2008 12:04am

i'd go with Snyper on this one,

i've installed a triple coil cylinder with dual immersion in my place, got the lads doing the solar panels to order the cylinder for me for an extra couple of euro

a pint of plain is yer only man

18-03-2008 9:44am

A standard HW cylinder is 120L so 300L is plenty for a 5 person house, remember that if you go too big then your just paying to heat extra water that wont get used

Gurgle · 18-03-2008 2:35pm

whitelightrider wrote: »

or is the 300 litre ok for a 2200 sq ft house?

Why, where and how did the idea get around that the size of cylinder should be chosen based on the size of the house?

AckwelFoley · 18-03-2008 4:30pm

Gurgle wrote: »

Why, where and how did the idea get around that the size of cylinder should be chosen based on the size of the house?

Its based on occupant numbers, ones reqirements for howater, however that said - a 2200 house is unlikely to house 15 people!

If he said 4000 sq ft, we could also assume there are at least 6 bedrooms...

It is always important to take into consideration the possible occupancy of a house. If a 4000 sq ft house is inhabited by only 2 people, you need to take into account the possibility of the house being sold on, and in that event the house could need alot more hot water if a big family move in

But assumptions are dangerous.. so lets not assume..

bertie1 · 18-03-2008 9:31pm

We have a 3000sq ft house & 450 ltr dual coil water tank . I have been in a three bedroom house 1100sqft with a 300ltr tank & it regularly drained down & then airlocked the system when the pumped showers were working

davidoco · 18-03-2008 11:27pm

bertie1 wrote: »

We have a 3000sq ft house & 450 ltr dual coil water tank . I have been in a three bedroom house 1100sqft with a 300ltr tank & it regularly drained down & then airlocked the system when the pumped showers were working

If you’ve got a 300ltr cylinder and your pulling out 15 or 20 litres per minute on a power shower, your standard 200 ltr cold water storage tank is not going to replace it quick enough leading to the air lock. The water coming into that house is not able to replenish the cold water storage tank quickly enough.

Self builders with their own wells can up the pressure on the cold water storage/install a bigger or another tank or just go pressurised therefore cutting out the cold water storage feeding the hot water.
Out of interest I have a 200 litre cylinder heated up to 70 degress and only about half is used to fill a 1800 x 800 bath for an adult (because of mixing) with more than enough for a shower afterwards. I actual had to change the feed from the cold tank to the thermostatic mixing from ¾ qualplex to ¾ copper to get more cold down to the taps.
IMO anything bigger than 300 ltr for domestic situations should be used as a buffer vessel with the hot water coming off that using a heat exchanger.

davidoco · 18-03-2008 11:37pm

Anybody with a big cylinder should have a look at this Resol display http://www.resol.de/en/english.shtml look under measurement instruments and see the Heat indication display CALVIO it costs about €200.

smooth operater · 19-03-2008 1:03pm

I thought the tank should be sized on the amount of solar?

So, op, how much solar are you using?

Mellor · 19-03-2008 1:30pm

smooth operater wrote: »

I thought the tank should be sized on the amount of solar?

So, op, how much solar are you using?

Even with zero solar, you stil need a hot water tank

smooth operater · 19-03-2008 1:36pm

Mellor wrote: »

Even with zero solar, you stil need a hot water tank

Yes im very much fully aware of that

But as pointed out, the usual is a 120litre tank.

He then noted that he was using solar. 120litre tank wouldn't be big enough if he was using 5m2 of solar. Going by the size of the tank the plumber has suggested, im guesing between 4-5m2 of solar is going to be used.

AckwelFoley · 19-03-2008 6:49pm

davidoco wrote: »

If you’ve got a 300ltr cylinder and your pulling out 15 or 20 litres per minute on a power shower, your standard 200 ltr cold water storage tank is not going to replace it quick enough leading to the air lock. The water coming into that house is not able to replenish the cold water storage tank quickly enough.

Self builders with their own wells can up the pressure on the cold water storage/install a bigger or another tank or just go pressurised therefore cutting out the cold water storage feeding the hot water.
Out of interest I have a 200 litre cylinder heated up to 70 degress and only about half is used to fill a 1800 x 800 bath for an adult (because of mixing) with more than enough for a shower afterwards. I actual had to change the feed from the cold tank to the thermostatic mixing from ¾ qualplex to ¾ copper to get more cold down to the taps.
IMO anything bigger than 300 ltr for domestic situations should be used as a buffer vessel with the hot water coming off that using a heat exchanger.

Good info imo

Mellor · 19-03-2008 9:03pm

smooth operater wrote: »

Yes im very much fully aware of that

But as pointed out, the usual is a 120litre tank.

He then noted that he was using solar. 120litre tank wouldn't be big enough if he was using 5m2 of solar. Going by the size of the tank the plumber has suggested, im guesing between 4-5m2 of solar is going to be used.

Sorry, I'm sure you were aware, wasn't trying to suggest otherwise. Just pointing it out for a layperson, they lurk about everywhere

Its true in a way that if you have such an amount of solar, you will need a tank to cope.
But if done correctly it is sized on the number of people, and then solar is also sized from the number of people, this means that you have optimised levels of solar and a tank to cope.

smooth operater · 20-03-2008 12:01pm

Mellor wrote: »

Sorry, I'm sure you were aware, wasn't trying to suggest otherwise. Just pointing it out for a layperson, they lurk about everywhere

Its true in a way that if you have such an amount of solar, you will need a tank to cope.
But if done correctly it is sized on the number of people, and then solar is also sized from the number of people, this means that you have optimised levels of solar and a tank to cope.

I see, im still riding the learning curve

Cylinder size

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