Jump to content

Hot water system ...


Featured Posts

His all, new to the forum and in the process of buying a n'boat, the boat in question will need a complete refit, I work as a small scale builder/odd jobber so have skills and friends with skills. I have a couple of questions for you guys regarding hot water systems..

 

So I know the calorifier takes heat from the engine coolant system, I am also intending to feed hot water from the stove back boiler system that heats radiators. What I want to know is.... can I then fit the instant gas water heater on the hot water outlet of the calorifier and have some sort of thermostatic switch that means the gas heater only fire's up when the water is below a set temp. I hate waste and would not be happy having the gas heater running while the water is plenty hot enough from the calorifiers, it would bug the he'll out of me. I guess the easiest option is to just switch the gas heater off when I know there is already hot water but I'm a tad forgetful so would end up forgetting to turn it on and off hence the idea of the thermostatic control....

 

The other question I have is calorifiers, damn they are hexpensivo. I am like most on a tight budget. I understand why you can't really use a domestic cylinder apart from size due to the pressure and the modern ss domestic tanks are no better price wise. Now I've done a fair bit of tinkering and fetteling in my time making chimeras from gas cylinders as well as inventing versions of things I can't afford to fit my needs etc. I also understand the process of purging the cylinders of gas and fumes etc. 

Could I. .. drill a hole the side/top of the gas cylinder for an emersion heater fitting and then 6 x normal 15mm holes and then have a long narrow pair of coils that will fit in the 2.5'' hole and connect to 'proper fittings' on the 15mm holes and then the cold in and hot out as normal and then use an emersion heater blanking plate to close the cylinder. I would obviously fit a pressure relief valve on the hot out feed so no issues with over pressurisation. Obviously the gas cylinder is rated at a far higher pressure rating and a 12kg cylinder would be a perfect size. (The cylinder is from a company that no longer exists so no ownership issues).

Do you guys that know see any other issues with this idea, I would obviously insulate the cylinder and while open I would coat the inside of the cylinder with a suitable paint/coating.

 

Thanks for any replies.

 

Steve.

Link to comment
Share on other sites

Not strictly true, you can do it but it will be dangerous with a high potential for scalding and possibly gas water heater damage so in effect the answer is no, don't do it. I also suspect the BSS may have something to say about it. If you are fitting to comply with the Recreational Craft Directive the relevant ISOs will prohibit it.

The only reason you can not use a domestic indirect cylinder is because of the pressure delivered as standard by the water pump. When I was on the hire fleet we did use indirect cylinders for the vertical installations but we always fitted a separate adjustable pressure switch and operated them well within their pressure rating. If you go down this route please also use an expansion vessel and a suitably rated PRV to minimise the pressure rise when the water is heated with closed taps.

Do you really want rusty water issuing from the hot taps? As far as I know gas bottles are not coated internally to prevent rust when in contact with water.

If you do operate at a lower pressure you would do well to stick with 15mm inlet, the modern 10mm tails or less mixer type taps may reduce the flow too much at say 10 to 15 PSI

Edited by Tony Brooks
More info
Link to comment
Share on other sites

One other thing to reduce waste and scalding. When the calorifier is fully at engine temperature it will probably be hotter than you need, so I would suggest a thermostatic mixer valve (about £20 from memory) to produce "warm" water at the required temp.

I use warm water in the bathroom and hot water in the galley (eg to fill the kettle).

Link to comment
Share on other sites

5 minutes ago, Scholar Gypsy said:

One other thing to reduce waste and scalding. When the calorifier is fully at engine temperature it will probably be hotter than you need, so I would suggest a thermostatic mixer valve (about £20 from memory) to produce "warm" water at the required temp.

I use warm water in the bathroom and hot water in the galley (eg to fill the kettle).

This is a very good idea, but make sure you read the spec of the mixer very carefully. When i first installed one, i found that i couldn't get any hot water when the engine was fully warmed up; i eventually found out that the mixer incorporated a safety device that shut down the mixing facility if the hot water input reached 80 degrees

Link to comment
Share on other sites

Thanks guys. 

I did wonder if the inline gas water heater would work, it's a shame really as it would make a complete 'in one' system. I was hoping there would have been a sensor/switch that would control the gas heater as the water passed through it sort of thing. I think the idea of a splitter valve sounds like my best bet. I don't fancy being dead again so it has to be safe....

As for the gas cylinder idea, no I did think about the rusty water which I would have found a suitable tanking type paint, pour it in, duct tape the holes and slosh the paint around until good coverage, drain and let dry and then repeat so a good internal coating. Interesting about using a presource relief valve on a domestic cylinder. I'm just looking for the best solution for the lowest cost but not skimping on safety or comfort.

Thanks for the replies, I'm sure I will have plenty of strange questions in the next few months. 

Steve.

Edited by Steve-H71
Link to comment
Share on other sites

26 minutes ago, Steve-H71 said:

Thanks for the replies, I'm sure I will have plenty of strange questions in the next few months. 

I think you will struggle to think of any questions that have not been asked before.

 

Most folks are 'boating on a budget' and some because they cannot afford to live anywhere else - I think that eventually you will find, as most others do, that actually the most economic way is the 'normal way', although it may not appear so at 1st sight.

 

The number of times I have looked at doing a job / making a widget and thought I can do it better / cheaper than that and have ended up buying components, disposing of them, buying more and eventually ending up with something that does not work as well as the 'proper' part would do, and costs more.

You will have years of work ahead of you in completely fitting out an old boat, don't make it harder on yourself than you need to.

  • Greenie 1
Link to comment
Share on other sites

So right you are Alan.  It's knowing which idea's are worth trying to find that alternative.  

I'm of the been divorced and need an affordable home although I've loved boats since a small child (now a big child as she told me.....)

The problem with the world today is everything is made to a price so it makes the most profit regardless, although not that old I remember when the cost of an item was relative to the cost of making it, sadly greed took over with a certain Mrs T.

For example I really want a composting toilet. I like the air head and nature's head type with the compost rotating system etc. Why the he'll does it cost 700 odd quid !!! I am building my own with 12v fan and removable compost box with rotator bars etc. The parts and materials cost me 150 quid. I will post the build pics once it's finished....

My biggest  issue with calorifiers are their cost, are they lined with gold, do they run on magic fairy dust. No its just a tank. So why so expensive.

Rant over.

Thanks for the replies. 

Steve.

 

  • Greenie 2
Link to comment
Share on other sites

2 hours ago, Alan de Enfield said:

I think you will struggle to think of any questions that have not been asked before.

 

Oh I dunno. I've not seen the one about a gas bottle as a calorifier before!

 

1 hour ago, Steve-H71 said:

For example I really want a composting toilet.

 

Really? Why??

 

1 hour ago, Steve-H71 said:

I like the air head and nature's head type with the compost rotating system etc. Why the he'll does it cost 700 odd quid !!! I am building my own with 12v fan and removable compost box with rotator bars etc. The parts and materials cost me 150 quid.

 

Once you've built it, would you sell it for significantly less than £700 and feel you've made a good and worthwhile commercial profit?

If not, there's your answer!

 

1 hour ago, Steve-H71 said:

My biggest  issue with calorifiers are their cost, are they lined with gold, do they run on magic fairy dust. No its just a tank. So why so expensive.

Rant over.

 

The same effect is at play here. They cost a lot because it is time consuming and expensive to form copper thick enough to withstand the pressure a boat system runs at. Along with the tiny volumes of production compared to domestic unvented cylinders (Which typically cost £750-ish), and the fact they take up loads of room to store in warehouses.

 

Welcome to the forum by the way!

Link to comment
Share on other sites

Slightly off the point but I've often wondered why stainless steel hasn't made an appearance as an alternative for HW storage.  On boats most folk are quite happy with it as a cold water tank, and presumably it can be made to cope with pressurised systems.   Maybe it just isn't any cheaper in that application?

Gas bottles are ok to make small solid fuel heaters but not hot water storage, there's nothing you can do to the inside to prevent corrosion. 

Link to comment
Share on other sites

I get the point's you made mike. I don't however see the problem with the gas cylinder. If it has an internal coating to inhibit rust and contamination then there is no reason it can't be used. Is it not tested at a far higher pressure than any hot water cylinder. If it has the correct plumbing fittings and pressure relief valve then it would be safe enough and would only cost the price of the fitting's. I don't suggest everyone rushes out chopping holes in gas cylinder's, if not done properly it can obviously be slightly dangerous.... but it would/will work.

I like and respect constructive criticism as it helps us see things from different perspective's. I understand your point though  mike regarding commercial profit. Its just sad that everything in this world has to come down to profit.

Link to comment
Share on other sites

Whoops pressed the wrong key. Anyway as I was trying to say Neil2 and assuming you weren`t just referring to the boating world have a look at ACV Smart. I`ve installed one in my house and although it only currently takes heat from the oil boiler I plan to add solar as well. It already has the immersion facility but I`ve never used it. They are expensive but a great investment as far as I`m concerned.

Link to comment
Share on other sites

31 minutes ago, Neil2 said:

Slightly off the point but I've often wondered why stainless steel hasn't made an appearance as an alternative for HW storage.  On boats most folk are quite happy with it as a cold water tank, and presumably it can be made to cope with pressurised systems.   Maybe it just isn't any cheaper in that application?

Gas bottles are ok to make small solid fuel heaters but not hot water storage, there's nothing you can do to the inside to prevent corrosion. 

Stainless steel is widely used - our 'Cat' has one.

Extract from the manual : -

MODELS BXS 25 / BXS 40
TANK CAPACITY
Liters 25 / 40
US gallon 6.6 / 10.56
Tank material AISI 316 Stainless steel
Thermal insulator Polyurethane foam
External cladding material AISI 304 Stainless steel
Tank pressure during testing 800 kPa (1)
Maximum working pressure 600 kPa (1)
Electric element voltage rating (2) 220 Vac ± 10% - (110 Vac ± 10%)
Electric element power 500 W [Model 05] - 600 W [Model 06] (4)  - 1200 W [Model 12]
Outputs diameter 1/2”
Weight Kg 10,5 / 13,9 Pounds 24.1 / 30.6

 

p-1655-BoilerBX25.jpg

Link to comment
Share on other sites

On 17/03/2017 at 20:28, Steve-H71 said:

I get the point's you made mike. I don't however see the problem with the gas cylinder. If it has an internal coating to inhibit rust and contamination then there is no reason it can't be used.

 

But it DOESN'T have an internal coating to 'inhibit' rust. But even if it did, 'inhibiting' rust isn't good enough. It needs 100% preventing, with no room for doubt.

 

 

On 17/03/2017 at 20:28, Steve-H71 said:

 Is it not tested at a far higher pressure than any hot water cylinder.

 

No it isn't. They are each tested to about the same IIRC. Have a google...

 

 

Link to comment
Share on other sites

3 minutes ago, Mike the Boilerman said:

Yet another one not reading the thread before sticking their oar in.

Yet another plumber without manners. Oh well . 

3 minutes ago, Mike the Boilerman said:

Yet another one not reading the thread before sticking their oar in.

 

  • Greenie 3
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.