Hot water cylinders

[chris_r]

I am planning a bathroom refit this year and would like to upgrade my present calorifier to something that will give a greater capacity of hot water. The Surecal range offers products up to about 90 litres vertical and a bit more horizontal ... and all at a substantial price. Browsing through eBay (as one does !) I can find reasonable sizes (125 litres) Unvented Indirect Hot Water Cylinders fairly regularly and at non eye watering prices.

 

Can these be used with safety in a marine environment or am I barking up the wrong tree here ?

 

Sage words of wisdom and advice welcome

[alan_fincher]

A marine calorifier is built to withstand a substantially greater pressure than a normal domestic hot water cylinder.

 

As even the real thing seems to split open sometimes, I'm guessing that using the thing not intended for the job is even more likely to!

[Marky_Mark]

they are very thin and would puncture quite easily if not well protected. they also need to be kept upright, No idea if they will work for what you want tho

[chris_r]

A marine calorifier is built to withstand a substantially greater pressure than a normal domestic hot water cylinder.

 

As even the real thing seems to split open sometimes, I'm guessing that using the thing not intended for the job is even more likely to!

 

I have picked up on previous threads about the dangers of using "domestic" hot water cylinders. It seems the type of cylinder I am looking at is pressure tested up to 12 bar ... these cylinders were permitted into domestic situations post a 1989 change in regulations.

[bottle]

I have not checked but do not the Surecal come with all the fittings, non return valve, pressure relief valve and a safety temperature control.

 

Do the ones on e-bay?

 

Make sure you compare like for like.

[chris_r]

I have not checked but do not the Surecal come with all the fittings, non return valve, pressure relief valve and a safety temperature control.

 

Do the ones on e-bay?

 

Yups ... good point about Surecal. The stuff I have seen on eBay will have various fittings as well as an expansion tank and immersion sticks. Take your point though.

 

Really just want to understand if these unvented domestic cylinders can be used a boaty system.

Make sure you compare like for like.

Edited March 18, 2011 by chris_r

[ditchcrawler]

I have picked up on previous threads about the dangers of using "domestic" hot water cylinders. It seems the type of cylinder I am looking at is pressure tested up to 12 bar ... these cylinders were permitted into domestic situations post a 1989 change in regulations.

The best I could find on ebay is 10 mt head. I don't think I have ever seen one rated at 12 bar

[Keeping Up]

The best I could find on ebay is 10 mt head. I don't think I have ever seen one rated at 12 bar

 

 

IIRC that's only about 1 bar

[chris_r]

This is the sort of thing I have been looking at

 

ebay linky

 

There is a click through on this item to the manufacturers datasheet

[bottle]

It only has one coil, calorifiers usually have two one fromthe engine and one from the 'central heating'.

 

It also says max temperature 70°C ( this may be the max of the immersion heater) if using the engine to heat, it varies, mine runs at 80°C.

 

Whether this has any bearing, I do not know

 

Note to others the link is for a 'mains' pressure hot water tank.

Edited March 18, 2011 by bottle

[ditchcrawler]

It only has one coil, calorifiers usually have two one fromthe engine and one from the 'central heating'.

 

It also says max temperature 70°C ( this may be the max of the immersion heater) if using the engine to heat, it varies, mine runs at 80°C.

 

Whether this has any bearing, I do not know

 

Note to others the link is for a 'mains' pressure hot water tank.

Must admit I was looking at traditional cylinders, it could be worth a punt at the right price.

[MtB]

 

Can these be used with safety in a marine environment or am I barking up the wrong tree here ?

 

Sage words of wisdom and advice welcome

 

The answer to your questions in my opinion are 'yes' and 'no' respectively.

 

Domestic unvented hot water cylinders perform the same function as marine calorifiers in that they are designed to operate at the range of pressure generally delivered by marine domestic water pumps. They seem to me to be far more suitable than copper calorifiers as, being made from stainless steel, they are not prone to the metal fatigue fractures that copper high pressure cylinders and calorifiers are well known for.

 

The down side is their physical size. If you have a widebeam I'd say they are very suitable. Not so easy if you have a narrowboat though as they must be installed upright and cannot be fitted under the bed. Unless you are happy with a very high bed :-)

 

Mike

[ChrisPy]

seems to me that new unvented indirect domestic hot water cylinders are no cheaper than boat calorifiers, unless you find a cheapy on ebay (second hand? possibly when the cylinder is rendered redundant by fitting a combi boiler).

[chris_r]

The answer to your questions in my opinion are 'yes' and 'no' respectively.

 

Domestic unvented hot water cylinders perform the same function as marine calorifiers in that they are designed to operate at the range of pressure generally delivered by marine domestic water pumps. They seem to me to be far more suitable than copper calorifiers as, being made from stainless steel, they are not prone to the metal fatigue fractures that copper high pressure cylinders and calorifiers are well known for.

 

The down side is their physical size. If you have a widebeam I'd say they are very suitable. Not so easy if you have a narrowboat though as they must be installed upright and cannot be fitted under the bed. Unless you are happy with a very high bed :-)

 

Mike

 

 

Mike, thanks for the fulsome answer. The biggest 90 litre Surecal calorifier is 820mm high and 505mm wide. The ebay example I posted is 150 litres capacity and 1155mm high but still only 505mm wide.

 

To my mind it just seems the opportunity to pick up a pre-owned domestic unvented hot water tank is far greater than find a marine calorifier of similar capacity ... and it also seems there are some good deals which can be found from the domestic market

 

I'm off to get my tape measure out and see what I can squeeze in. If I do find I am short of space then maybe i can just swap my engine for a nice single cylinder and get some more room in the bathroom

 

seems to me that new unvented indirect domestic hot water cylinders are no cheaper than boat calorifiers, unless you find a cheapy on ebay (second hand? possibly when the cylinder is rendered redundant by fitting a combi boiler).

 

Exactly my thinking

[RobinJ]

They seem to me to be far more suitable than copper calorifiers as, being made from stainless steel, they are not prone to the metal fatigue fractures that copper high pressure cylinders and calorifiers are well known for.

Are you sure?

It mentions enamelled steel not stainless, I would have thought if stainless they would be very expensive?

 

The marine calorifiers are designed for purpose, come with plenty of insulation and are rated at a higher pressure than domestic copper cylinders (~20psi). However we had a small copper cylinder fitted to our cruiser which was very effective. If you have the space and ability to handle the expansion, then provided they are insulated properly a normal domestic cylinder is an option.