Conventional gas boiler on a boat

[Noviceboata]

Hi All,

 

Quiete new to boating and just after some information about heating the boat. Was looking at a boat to buy and the heating system with radiators and hot water will come from a conventional combi boiler(the home type) I have read their is a specialist combi boiler called Alde for boats.

Is there any reason why conventional boilers are not mainstream on boats considering they seem cheeaper that other options including diesel boiler setups? Does the conventional boiler use a lot of gas compared to the Alde? Is a diesel setup more efficient?

[GUMPY]

A Combi boiler will eat it's way very quickly through 13kg cylinders even an Alde will use a lot of gas, mine was using a 13kg in a week when it was my only source of heat.

If the boat is big enough then a domestic oil boiler may be the best way to go but unless you can convert it it will need a constant supply of 230volts.

 

[reg]

Removed my alde, why ?

far to expensive to run on 13kg calor 

Far to many little problems after leaving unused for a while 

Allowed me to remove some on-board gas connections, the less the better in my book.

Battery drainer in winter had to run engine to power it sometimes.

A small factor was also that the experienced alde engineer who liked working on boats retired which took a safety net away.

 

Basically I had to many little problems.

I have, after a long gap, now fitted a reconditioned Webasto thermotop C which is, after some installation teething problems, very much better.

 

EDIT: MY COMMENTS ARE FOR THE OLDER STYLE TALL 2928 model

 

 

 

Edited May 27, 2022 by reg
Clarify model number

[reg]

51 minutes ago, Loddon said:

mine was using a 13kg in a week

I dreamed of that sort or efficency, lucky to get 2 or 3 days which at todays prices works out at about £14 - £20 a day.

Plus, if you are cruising, the extra hassle and expense of locating and  traveling to a calor supplier.

[MtB]

7 minutes ago, reg said:

I have, after a long gap, now fitted a reconditioned Webasto thermotop C which is, after some installation teething problems, very much better.

 

 

I've just bought one of those too. Could you expand a little on the teething problems you've had please? I'd be most interested before I set about fitting mine!

 

Thanks...

 

 

[Noviceboata]

13 minutes ago, reg said:

I dreamed of that sort or efficency, lucky to get 2 or 3 days which at todays prices works out at about £14 - £20 a day.

Plus, if you are cruising, the extra hassle and expense of locating and  traveling to a calor supplier.

Did you end up changing your heating system? what do you think about deisel heating systems?

[mrsmelly]

7 minutes ago, AndrewKyiv said:

Did you end up changing your heating system? what do you think about deisel heating systems?

Solid fuel stove. End of.

15 minutes ago, MtB said:

 

 

I've just bought one of those too. Could you expand a little on the teething problems you've had please? I'd be most interested before I set about fitting mine!

 

Thanks...

 

 

Did you buy an ebay special?

[MtB]

1 minute ago, mrsmelly said:

 

Did you buy an ebay special?

 

Yep! Out of curiosity really, and because the Whispergen was playing up.

[mrsmelly]

Just now, MtB said:

 

Yep! Out of curiosity really, and because the Whispergen was playing up.

I had one from a bloke called MP and H iirc. Spot on bit of kit, worked faultlessly. It was so good I bought a second from him. I had it ready so when other needed a service I quickly removed and replaced with the other so no down time, a great spare. Now you know all about this stuff but one tip was, I had valve thingies on each innie outy so I could isolate the system and lose nearly zero water each time I removed a unit and swopped the other one in. Also all pipe work was 22 mil through boat in a loop with rads td off in 15 mil, but you know that 

[GUMPY]

29 minutes ago, reg said:

I dreamed of that sort or efficency, lucky to get 2 or 3 days which at todays prices works out at about £14 - £20 a day.

Plus, if you are cruising, the extra hassle and expense of locating and  traveling to a calor supplier.

To be fair I can't remember exactly how much possibly 3 every two weeks seems to ring a bell

[reg]

43 minutes ago, MtB said:

 

 

I've just bought one of those too. Could you expand a little on the teething problems you've had please? I'd be most interested before I set about fitting mine!

 

Thanks...

 

 

Shouldn't be a problem for you with your background  in my case I had tightened a pipe clip too near the end of the pipe so it allowed a slight air leak and stopped a clean start up.

Had to be the one which was hardest to see and get to. Once found then had no other real problems.

I don't think you , with your experience, should have a problem.

EDIT TO ADD

I had to source some alternative hose clips as the supplied quality items seemed to be to small. I thought it was me originaly but then I found a post somewhere where a regular installer stated he always replaced the supplied hose clips.

Edited May 27, 2022 by reg
Additional info

[blackrose]

1 hour ago, MtB said:

 

Yep! Out of curiosity really, and because the Whispergen was playing up.

 

I've had good results from an ebay Thermotop C, however it's my second unit because the circuit board on the first one was sending the thing haywire. By the time I got around to fitting the first one the 3 month warranty had long expired and the ebay seller was nowhere to be found. So I bought a second one which worked really well over last winter and I bought a replacement ebay circuit board for the first one, so I've always got a working spare.

 

I've heard that the ebay Webastos aren't marine units so they operate at a higher voltage - because a truck battery will always be fully charged I suppose? Anyway, that's not a problem for me because I'm only really using mine during winter when the boat's hooked up to shore power with a charger on float. The other thing is that the exhaust that comes with most non-marine ebay kits aren't designed for boats. It's easy enough to seal the non marine exhausts though, with a stainless bolt a and a bit of high temp Envirograf sealant. Just hold your hand over one end and blow into the other to make sure it is sealed.

 

I fitted mine with a Delphi/CAV water separator/sediment trap on the diesel feed. Seems to work well and will be cheap to replace the elements. The only other thing I can think of is to make sure that the kW output of all your rads and pipework match the kW output of the heater. Ignore any calorifier because once that's hot it's won't count. A lot of boat C/H installations are undersized meaning the water comes back to the boiler still hot and the thing cycles down and cokes up. You want it running hard.

 

I feel like I'm teaching you to suck eggs... 🥚

 

Edited May 27, 2022 by blackrose

[reg]

8 minutes ago, blackrose said:

I've heard that the ebay Webastos aren't marine units so they operate at a higher voltage

Good point that I forgot to mention 

The marine version has a different ecu

To the standard version. Primary reason is that the standard version assumes a vehicle battery is also required for starting so it cuts out at 11.8v DC whereas the marine version doesn't cut out until 10.5v DC.

So make sure you get the marine version. I believe the ecu can be swapped out but I also understand that it is an expensive option.

 

Edited May 27, 2022 by reg
.

[MtB]

5 minutes ago, reg said:

To the standard version. Primary reason is that the standard version assumes a vehicle battery is also required for starting so it cuts out at 11.8v DC whereas the marine version doesn't cut out until 10.5v DC.

 

Ah thanks. I've often wondered what the exact difference is. I think I prefer the automotive cut-off voltage anyway! 10.5V would mean your domestics have been taken down to 0% SoC. 

[Alan de Enfield]

8 minutes ago, MtB said:

 

Ah thanks. I've often wondered what the exact difference is. I think I prefer the automotive cut-off voltage anyway! 10.5V would mean your domestics have been taken down to 0% SoC. 

 

Some time ago 'NMEA' (who is a Webby dealer / service agent) detailed the differeneces between the auotomotive and marine heaters.

 

The big 'electronics' difference was not cut-off voltage, but the 'start-up voltage' as it 'assumed' that being connected to the starter battery it would always be 99+% charged.

From memory the automotove one struggled to start if your domestic bank was below (something like) 12.6v. which boat domestic batteries could often be after running a fridge &/or freezer etc overnight.

 

There was other 'electronics' variations but the other 'biggy' was the non-marine exhaust that allowed exhaust gas into your bilges, where as on a vehicle, they just 'escaped' thru the engine 'hole' to the ground.

[Tracy D'arth]

14 minutes ago, MtB said:

 

Ah thanks. I've often wondered what the exact difference is. I think I prefer the automotive cut-off voltage anyway! 10.5V would mean your domestics have been taken down to 0% SoC. 

That is 10.5v under load at the heater in the start up phase, it won't pull the battery that low. I understand that with the correct cable you can reprogram the drop out voltage.

The auto version cuts off far too soon. We had three of these on boats and they would only run for an hour or so after mooring up for the night and next morning they failed to start up.

[BEngo]

Back to the OP.  I doubt that on a boat you could install a domestic type gas boiler, with approved LPG conversion, in accordance with the maker's installation and commissioning instructions.  That would mean that it cannot  pass the BSS and I expect it would not comply with the RCR (regs not the boat menders).

 

N

[Opener]

Back to another aspect of the OP query. I'm in the process of replacing an existing Alde. Mine is the older vertical/tall Comfort. Know nothing about the newer 'small box' types.

My Comfort was used solely for heating a calorifier's worth of hot water. Did so quite happily in about 30-40 mins. 13kg gas lasted ages (fair weather/occasional boater). 

Was also linked to CH but useless since it used finned rads in boxed trunking - I could only tell it was on by holding my hand over the vents in the trunking.

Old style Alde fine for water heating although I see gas is going up by £10 each time I need a replacement 13kg - I'm giving up on it primarily 'cos the spark ignition needs replacing every Spring - it doesn't seem to like Winter and replacements - hen's teeth😕🥴.

I wouldn't fancy fitting a domestic gas boiler - too expensive to connect to the mains!!

[PeterF]

One of the key differences between domestic and what is normally fitted is the rating. A narrowboat manages with a 5kW diesel boiler and that can end up short cycling. The smallest domestic appears to be around 10kW so will be well oversized.

 

A second difference is size, the diesel heaters are very compact compared to domestic boilers and space is at a premium.

[reg]

51 minutes ago, Opener said:

Back to another aspect of the OP query. I'm in the process of replacing an existing Alde. Mine is the older vertical/tall Comfort. Know nothing about the newer 'small box' types.

My Comfort was used solely for heating a calorifier's worth of hot water. Did so quite happily in about 30-40 mins. 13kg gas lasted ages (fair weather/occasional boater). 

Was also linked to CH but useless since it used finned rads in boxed trunking - I could only tell it was on by holding my hand over the vents in the trunking.

Old style Alde fine for water heating although I see gas is going up by £10 each time I need a replacement 13kg - I'm giving up on it primarily 'cos the spark ignition needs replacing every Spring - it doesn't seem to like Winter and replacements - hen's teeth😕🥴.

I wouldn't fancy fitting a domestic gas boiler - too expensive to connect to the mains!!

Pretty much how I used mine hot water only hence, when it's started to play up, I gave up on it. Model and spare parts long ago discontinued and apparently, according to Caravan World, so has tech support 

Caravan World Forum 2020

"I had this reply from them:

Technical support for the 292X-series was discontinued many years ago now, and no spare parts are available for them either."

 

I think they were very much of their day. Newer model may still be valid for caravans but I wouldn't countenance their installation in narrowboats nowadays.

 

Edited May 27, 2022 by reg
.

[Opener]

11 minutes ago, reg said:

Pretty much how I used mine hot water only hence, when it's started to play up, I gave up on it. Model and spare parts long ago discontinued

 

I've got plenty of parts. Clearing out preparatory to removal of Alde Comfort, I've put together about five spark generators. ........none of them work, mind!! 😟

[GUMPY]

35 minutes ago, PeterF said:

One of the key differences between domestic and what is normally fitted is the rating. A narrowboat manages with a 5kW diesel boiler and that can end up short cycling. The smallest domestic appears to be around 10kW so will be well oversized.

 

A second difference is size, the diesel heaters are very compact compared to domestic boilers and space is at a premium.

Domestic boilers are designed to run for any period so short cycling is not a problem. They  work in a completely different way to eberspacher/webasto etc.

[MtB]

1 hour ago, PeterF said:

One of the key differences between domestic and what is normally fitted is the rating. A narrowboat manages with a 5kW diesel boiler and that can end up short cycling. The smallest domestic appears to be around 10kW so will be well oversized.

 

A second difference is size, the diesel heaters are very compact compared to domestic boilers and space is at a premium.

 

Domestic gas boilers all modulate to match the heat load attached nowadays. There is a parameter called the "turndown ratio" which is the ratio of the max output:min output it will reduce to before turning OFF. A turndown ratio of 10:1 is not unusual nowadays so even a 30kW domestic gas boiler can be expected to adjust its output down to as low as 3kW if necessary. I think the very best turndown ratio I've heard of is something like 14:1. 

 

If the 10kW domestic boiler you mention has a turndown ratio of even 7:1, the output will go as low as 1.7kW. Low enough for any narrowboat I'd have thought. But as you point out, they are all massive in physical size and they require mains 230Vac 24/7 to work, so the inverter has to be ON all the time.