Best calorifier

[Strettonman]

I am just about to hit the ‘buy’ button for a 55ltr twin coil surecal calorifier and just thought I should double check it’s all it’s cracked up to be. The reviews seem pretty good but what’s the opinion of the forum members ? 

[cuthound]

Surecal calorifiers are generally reckoned to be one of the best.

 

However that are made from stainless steel, which hardens and cracks if the calorifier is repeatedly pressurised and released, which can happen if the PRV becomes faulty. 

 

Best to install an expansion vessel to prevent this.

 

If it is second hand, make sure it has not cracked. If it has it will leak.

Edited May 5, 2019 by cuthound
Spillung

[Strettonman]

I was planning go for copper coils and buy new. I was also going to fit an expansion tank as well. 

I presume stainless steel lasts longer but I gather there are a few issues. 

Any thoughts ?

[alan_fincher]

1 hour ago, cuthound said:

Surecal calorifiers are generally reckoned to be one of the best.

 

However that are made from stainless steel, which hardens and cracks if the calorifier is repeatedly pressurised and released, which can happen if the PRV becomes faulty. 

 

Best to install an expansion vessel to prevent this.

 

If it is second hand, make sure it has not cracked. If it has it will leak.

 

Is that meant to read "they are made from stainless steel"?

If so, I don't think that is couurect us it?  The standard Surejust/Surecal offering is generally a copper cylinder.

[WotEver]

10 minutes ago, alan_fincher said:

The standard Surejust/Surecal offering is generally a copper cylinder.

Yup, that’s what it says here, “100% copper”...

http://www.surejust.co.uk/55-litre-vertical-twin-coil-surecal-calorifier

[MtB]

2 hours ago, cuthound said:

Surecal calorifiers are generally reckoned to be one of the best.

 

However that are made from stainless steel, which hardens and cracks if the calorifier is repeatedly pressurised and released, which can happen if the PRV becomes faulty. 

 

 

My experience is the opposite. Copper cylinders work harden and split, stainless steel ones don't. 

 

This is why copper is pretty much unheard of in household mains pressure cylinders now, and stainless steel is always used. 

 

[Tony Brooks]

Also if you have an Alde 3xxx gas boiler they say copper plumbing will corrode their aluminium heat exchanger.

[BruceinSanity]

The SureCal warranty is conditional on an expansion vessel being fitted, presumably for the reasons discussed.

[blackrose]

When I was at a boat show once I saw some very expensive calorifiers. I think they were made of stainless but can't remember. When I asked why they were so pricey I was told that they were proper marine calorifiers and the ones we use on canal boats were basically cheap modified domestic cylinders.

[Tony Brooks]

25 minutes ago, blackrose said:

When I was at a boat show once I saw some very expensive calorifiers. I think they were made of stainless but can't remember. When I asked why they were so pricey I was told that they were proper marine calorifiers and the ones we use on canal boats were basically cheap modified domestic cylinders.

Modified in what way should have been the question. Yes, the copper is normally thicker than on a non-mains pressure domestic cylinder but the rest is likely to be the same as any indirect cylinder. They might claim that they have "crimped" the coils to give faster heat transfer but you can get "fast recovery" domestic cylinders. Sounds to me like trying to justify a huge marine markup.

[Strettonman]

I am now questioning copper over stainless steel coils. Price difference is less than 10% but assumed copper was the norm and only fitted stainless steel if you had a gas boiler with aluminium heat exchanger. 

I am starting off with heating from engine and stove as we are not planning to live aboard. If in the future we get hooked and take off for a year we might switch the stove coil to a boiler. 

I guess for future proofing paying £50 now to go for SS might be worth it as long as there are no downsides. The ‘cracking’ issue is unclear whether SS is better or worse but are there other issues I should take into account ? 

[Strettonman]

Also I can’t find a standard twin coil with 22mm for the stove feed. I gather this is best for gravity systems to minimise flow restrictions. It’s only a 40ft boat so do I made do with 15mm coils or do I need to shell out on a custom built calorifier ? 

[MtB]

1 hour ago, Strettonman said:

The ‘cracking’ issue is unclear whether SS is better or worse

 

It is NOT 'unclear'. Stainless cracking is virtually unheard of. I've certainly never seen one cracked. I've seen dozens if not hundreds of split copper cylinders though.

 

 

[dor]

I've got a SS calorifier and it has been fine for 12 years.  I used a SS one as I have a 3010 boiler, which has worked faultlessly without any intervention (i.e. no servicing required) for those 12 years.

[Guest]

15 hours ago, Strettonman said:

I am just about to hit the ‘buy’ button for a 55ltr twin coil surecal calorifier and just thought I should double check it’s all it’s cracked up to be. The reviews seem pretty good but what’s the opinion of the forum members ? 

Our  Surecal is 15 years old and has seen about 75% liveaboard use. From what I saw when changing the immersion heater, I am pretty certain it is of copper construction. We use it for heat recovery from the engine cooling system and occasionally the immersion. We have the normal PRV as well as an expansion vessel in the hot system, which I understand makes for an easier life for the calorifier. I would be tempted by a stainless one if I had to replace it, though must say I know of a few stainless water tanks that have given up the ghost, and they aren't usually pressurised in any way.

Edited May 6, 2019 by Guest

[cuthound]

1 hour ago, Mike the Boilerman said:

 

It is NOT 'unclear'. Stainless cracking is virtually unheard of. I've certainly never seen one cracked. I've seen dozens if not hundreds of split copper cylinders though.

 

 

 

Just before I bought my boat, the calorifier had cracked and been replaced. I don't know whether the original was copper or stainless steel, but the replacement is stainless steel.

 

I assumed that the replacement would be the same as the original.

[blackrose]

1 hour ago, dor said:

I've got a SS calorifier and it has been fine for 12 years.  I used a SS one as I have a 3010 boiler, which has worked faultlessly without any intervention (i.e. no servicing required) for those 12 years.

I've got a copper calorifier that's been ok for 15 years, but on the other hand I had a friend with the same one that split after only a year. 

[Guest]

38 minutes ago, blackrose said:

I've got a copper calorifier that's been ok for 15 years, but on the other hand I had a friend with the same one that split after only a year. 

It does seem to be something of a lottery. 
Out of curiosity, did either you or your friend's set up have an expansion vessel on the hot water side?
Cheers.