On Demand Propane Water Heater?
- Thread starter Stephen Trapani
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Hey, Seattle Scott, I'd be interested to hear how it goes. Or anyone else with the Excel, for that matter.
You must learn showering on your own. you may run the water at a high rate and suffer under slightly warm water or more slowly and have a nice hot shower.
I wonder how much propane these things burn. We have one at home that is 190,000 BTU's. It makes taking long showers very nice. You can fill up a hot tub with it.
Some considerations from the ABYC:
From A-26
26.5.1 LPG and CNG fueled appliances shall not be installed in spaces containing internal combustion engines,their fuel tanks, or joints and fittings of their fuel systems.
26.5.3 Appliances shall meet the combustion requirements of ANSI Z 21.57 Recreational Vehicle Cooking Gas Appliances.
26.5.4 Printed instructions for proper installation, including air intake and exhaust systems, operation, and maintenance shall be provided with each appliance.
26.5.4.1 The instructions shall include information on the risks associated with the air consumption of the appliance, and
26.5.4.1.1 venting of combustion products from the appliance.
26.5.5 A burner system shall be capable of operation without creating a fire hazard during periods of boat pitch and roll, at angles up to 30° from horizontal in any direction, and continuous operation at angles of heel up to 30°.
26.5.6 Operating controls shall be located to be easily accessible, and to minimize possible injury from burners or elements when being used.
26.5.7 Appliance controls shall be designed to require a push-turn or other two phase operation when going from “off” to “on” position.
26.5.8 The design and installation of LPG and CNG appliances and systems shall provide for the consumption of air and the venting of exhaust products.
26.5.9 Pilot lights and other automatic ignition devices shall be permitted only in appliances with room sealed combustion systems.
26.5.10 Unattended appliances shall incorporate a room sealed combustion system.
26.5.11 Attended non-room sealed combustion system appliances shall be equipped with an oxygen depletion sensor that cuts off the fuel supply to the appliance when the room oxygen level falls below 95% of normal, and/or failure of oxygen depletion sensor.
26.5.11.1 In addition to the oxygen depletion sensor, the manufacturer of the appliance shall provide a warning label to alert the appliance operator to maintain adequate ventilation during appliance operation.
26.5.12 All appliances shall have flame failure devices on all burners, and pilot lights, that will prevent gas from flowing to the burner if flame is not present.
26.5.13 When operating at the rated capacity, the exterior surfaces of the appliance shall not exceed 180°F (82°C) when tested in an ambient temperature of 77°F (25°C), and
26.5.13.1 the appliance shall be designed so that, when installed, the temperature of the surface below, and
immediately surrounding vertical combustible surfaces, shall not rise more than 150°F (65°C) above the compartment’s ambient temperature.
26.5.14 Appliances shall be mounted in accordance with the manufacturer's instructions and in accordance with this
standard.
26.6.1 Exhaust products shall be ducted to the exterior of the vessel and designed to minimize water entry, back draft, and exhaust re-entry through any hull openings, ventilators, opening ports, hatches, windows.
26.6.2 Flues shall be routed and sized to ensure complete discharge of the products of combustion outside the craft, and shall not be obstructed by an accumulation of water.
26.6.2.1 The flue system shall be continuous and sealed from the appliance to its terminus outside the craft.
26.6.2.2 Flue terminus shall not be positioned within 20 inches (500mm) of a refueling fitting or fuel tank vent.
27.6.2.3 Dampers, i.e., shut-off valves, shall not be installed in flue systems.
27.6.2.4 The flue system shall be accessible for inspection.
26.6.2.5 Exposed surfaces of flues, smoke pipes, or stacks in accommodation spaces shall not have a surface temperature greater than 180°F (82°C) during operation with a compartment ambient temperature of 77°F (25°C).
26.6.3 Double or triple wall smoke stacks shall meet the requirements of UL 103 Chimneys, Factory-built, and shall be installed in accordance with the instructions of the manufacturer.
Definitions:
Unattended Appliance - appliances intended to function without frequent attention by an operator, and that may cycle
on and off automatically, such as refrigerators, thermostatically controlled cabin heaters, and water heaters.
Room Sealed Combustion System - a combustion system in which incoming air, the combustion chamber, and the
outgoing products of combustion are sealed from the boat interior.
From A-26
26.5.1 LPG and CNG fueled appliances shall not be installed in spaces containing internal combustion engines,their fuel tanks, or joints and fittings of their fuel systems.
26.5.3 Appliances shall meet the combustion requirements of ANSI Z 21.57 Recreational Vehicle Cooking Gas Appliances.
26.5.4 Printed instructions for proper installation, including air intake and exhaust systems, operation, and maintenance shall be provided with each appliance.
26.5.4.1 The instructions shall include information on the risks associated with the air consumption of the appliance, and
26.5.4.1.1 venting of combustion products from the appliance.
26.5.5 A burner system shall be capable of operation without creating a fire hazard during periods of boat pitch and roll, at angles up to 30° from horizontal in any direction, and continuous operation at angles of heel up to 30°.
26.5.6 Operating controls shall be located to be easily accessible, and to minimize possible injury from burners or elements when being used.
26.5.7 Appliance controls shall be designed to require a push-turn or other two phase operation when going from “off” to “on” position.
26.5.8 The design and installation of LPG and CNG appliances and systems shall provide for the consumption of air and the venting of exhaust products.
26.5.9 Pilot lights and other automatic ignition devices shall be permitted only in appliances with room sealed combustion systems.
26.5.10 Unattended appliances shall incorporate a room sealed combustion system.
26.5.11 Attended non-room sealed combustion system appliances shall be equipped with an oxygen depletion sensor that cuts off the fuel supply to the appliance when the room oxygen level falls below 95% of normal, and/or failure of oxygen depletion sensor.
26.5.11.1 In addition to the oxygen depletion sensor, the manufacturer of the appliance shall provide a warning label to alert the appliance operator to maintain adequate ventilation during appliance operation.
26.5.12 All appliances shall have flame failure devices on all burners, and pilot lights, that will prevent gas from flowing to the burner if flame is not present.
26.5.13 When operating at the rated capacity, the exterior surfaces of the appliance shall not exceed 180°F (82°C) when tested in an ambient temperature of 77°F (25°C), and
26.5.13.1 the appliance shall be designed so that, when installed, the temperature of the surface below, and
immediately surrounding vertical combustible surfaces, shall not rise more than 150°F (65°C) above the compartment’s ambient temperature.
26.5.14 Appliances shall be mounted in accordance with the manufacturer's instructions and in accordance with this
standard.
26.6.1 Exhaust products shall be ducted to the exterior of the vessel and designed to minimize water entry, back draft, and exhaust re-entry through any hull openings, ventilators, opening ports, hatches, windows.
26.6.2 Flues shall be routed and sized to ensure complete discharge of the products of combustion outside the craft, and shall not be obstructed by an accumulation of water.
26.6.2.1 The flue system shall be continuous and sealed from the appliance to its terminus outside the craft.
26.6.2.2 Flue terminus shall not be positioned within 20 inches (500mm) of a refueling fitting or fuel tank vent.
27.6.2.3 Dampers, i.e., shut-off valves, shall not be installed in flue systems.
27.6.2.4 The flue system shall be accessible for inspection.
26.6.2.5 Exposed surfaces of flues, smoke pipes, or stacks in accommodation spaces shall not have a surface temperature greater than 180°F (82°C) during operation with a compartment ambient temperature of 77°F (25°C).
26.6.3 Double or triple wall smoke stacks shall meet the requirements of UL 103 Chimneys, Factory-built, and shall be installed in accordance with the instructions of the manufacturer.
Definitions:
Unattended Appliance - appliances intended to function without frequent attention by an operator, and that may cycle
on and off automatically, such as refrigerators, thermostatically controlled cabin heaters, and water heaters.
Room Sealed Combustion System - a combustion system in which incoming air, the combustion chamber, and the
outgoing products of combustion are sealed from the boat interior.
So would you install one of these water heaters in it's own box with a cowl vent to feed and exhaust it?
I could live with a 20 gal propane tank in a propane locker in the stern, a continuous hose from tank to heater, and a sealed little box in a cabinet with a plexiglass front so I could see and access it and a cowl vent. But I wonder what that salt air would do to it.
I would not personally install a vent-less on-demand propane water heater on any boat unless it met the applicable minimum safety standards and could hit all the criteria posted above. I have yet to see one that does meet the applicable criteria but I am always looking.
While there are many parts of A-26 these water heaters do not meet my most simple criteria is this:
26.5.10 Unattended appliances shall incorporate a room sealed combustion system.
This means that the unit must be vented and also must take combustion air from outside the boat in a sealed combustion manner, meaning exhaust vents out side the vessel and intake air also comes from out side the vessel. Usually a dual wall vent pipe is used with make up air coming in around the out side of the inner vent pipe to also help keep it cool though some appliances use a two vent system..
A water heater meets the ABYC definition of an "unattended appliance" a galley stove is an "attended appliance".
Unattended Appliance - appliances intended to function without frequent attention by an operator, and that may cycle
on and off automatically, such as refrigerators, thermostatically controlled cabin heaters, and water heaters.
Stephen's eBay heater linked to in the OP claims: Certifications - ISO 9001 Standards
These are NOT standards used in the water heater industry other than for "manufacturing excellence". It is rather ludicrous to claim ISO 9001 as a "standard" as far as water heaters go. How about NSF? It carries no ANSI, ASME, ABYC, AGA (American Gas Association), DOT (they claim it safe for RV's), NSF, UL or any other of the many standards a water heater could at least try to meet.
For example a residential State Industries On-Demand water heater, State Industries is a reputable water heater manufacturer, meets NSF, ANSI Z21.10.3., CSA 4.3, ASHRAE 90.1b, UL and ASME just to name a few.
Just because a manufacturer makes "claims" does not mean they are legitimate claims or in the slightest bit true if you want to do things to current and accepted safety standards.
Old regs?
That A-26 reg looks like it was written before the ventless gas appliance was invented, or they would have a clause about it.
That A-26 reg looks like it was written before the ventless gas appliance was invented, or they would have a clause about it.
The so called unvented gas appliances are not to be used in rooms that are restricted in their air supply. All gas burners must be vented in some manner. If they burn a large volume of gas they also consume very large volumes of air and produce large volumes of co2 and h2o along with a whole bunch of burned contaminates that are also in the gas.
An on demand water heater will have a burner capable of 36,000 btu's per hour. That is substantial and should in my opinion be vented.
A-26 has been around a long while but had its most recent major overhaul/re-write in July 2006 when "ventless" appliances were plentiful. The vent-free concept is not new but one that does not apply well to small boats.
The reason they don't have a "clause" for ventless appliances may lead back to the Paloma Pack incidences back in the 80's when folks were killed. If you read it carefully there is a "clause" and that clause is the entire standard which is suggesting against using "ventless" unattended appliances on boats, hence the strong wording and language such as
"Unattended appliances shall incorporate a room sealed combustion system."
or
"Appliances shall meet the combustion requirements of ANSI Z 21.57 Recreational Vehicle Cooking Gas Appliances."
That ABYC A-26 clause is basically suggesting that vent free water heaters, on boats, are not an acceptable safety risk.
It's your boat, you can always do what you want, but you might want to check with your insurance company before installing an LPG appliance that may not meet basic industry safety standards.
It is an "attended appliance" and has a specific exception.
Attended Appliance - an appliance that is installed in the cabin of a boat and used when the occupants are in the accommodation space in which the appliance is installed, and that requires frequent attention by an operator, such as cooking stoves and ovens.
Aft railing?
So how about my idea of putting the on demand propane heater on the aft railing, outside the cabin?
So how about my idea of putting the on demand propane heater on the aft railing, outside the cabin?
Looking at the Paloma deaths, it seems they were all from carbon monoxide poisoning. Wouldn't a good CO detector solve that issue?
I can see where an on demand ventless water heater could be considered an attended appliance. It only gets used while you are there using water, and you know exactly when it will be on and off, just like a stove.
There is a Mr.Heater propane heater that has a low O2 shutoff. There have been threads on here where the consensus was that they were fine for heating the cabin, though it is ventless. The major difference here is you can sleep while a heater is running. You are awake and aware that the W/H is active and burning fuel in the cabin.
MS-your point about this particular company citing their product is 9001ISO is laughable. That really just means it's made in Taiwan or China and the 8 year olds assembling it are given time off for meeting production. They have that designation for trade status not to say anything about their product. The fact that they didn't seek any certification for the product makes me think it is foreigners in charge of marketing. Maybe it is a good product but how would you know?
There is a Mr.Heater propane heater that has a low O2 shutoff. There have been threads on here where the consensus was that they were fine for heating the cabin, though it is ventless. The major difference here is you can sleep while a heater is running. You are awake and aware that the W/H is active and burning fuel in the cabin.
MS-your point about this particular company citing their product is 9001ISO is laughable. That really just means it's made in Taiwan or China and the 8 year olds assembling it are given time off for meeting production. They have that designation for trade status not to say anything about their product. The fact that they didn't seek any certification for the product makes me think it is foreigners in charge of marketing. Maybe it is a good product but how would you know?
How will it handle the elements? Is it designed for outdoor installations? How will you route the water supply to it? The LPG supply?
Remember it is your boat you can do what you want to I am just posting relevant accepted safety standards. If you've read the standards and think buying an ISO9001 water heater then by all means go for it. It still does not meet the minimum suggested safety requirements of ABYC A-26 which may get you flagged on an insurance survey. Me, I'd spend the money on a dedicated marine rated unit, perhaps one that can be heated off the engine and electrically.
I think that there are alternatives that are safer and just as acceptable as an on demand water heater. The pleasure of a hot shower is not worth the potential risk to life and boat. We don't need to shower every day in cold weather and if we haven't started to smell gamey we don't even need to wash.
What is the buzz??
I've been using hot water on boats now for a while and I have noted that:
At the slip there seems to be only one limit on how much hot water I have. That being the size of the fresh water tank.
Away from the slip I do have to be conscious of how much hot water there is between engine running cycles but I can't recall anyone on board taking a cold shower lately.
With that said:
Just how long a shower are you folks taking? The Admiral and I average 2 gallons each which leaves 6 gallons for dishes. Perhaps I can interest you in my Admiral 1.01 software upgrade that includes electric, water, hot water, and beer conservation modes. The great thing about this upgrade is all the conservation modes can be in operation at the same time. The software includes an AI feature to continually optimize its performance and all the modes are user tunable to boot.
I highly recommend it.
I've been using hot water on boats now for a while and I have noted that:
At the slip there seems to be only one limit on how much hot water I have. That being the size of the fresh water tank.
Away from the slip I do have to be conscious of how much hot water there is between engine running cycles but I can't recall anyone on board taking a cold shower lately.
With that said:
Just how long a shower are you folks taking? The Admiral and I average 2 gallons each which leaves 6 gallons for dishes. Perhaps I can interest you in my Admiral 1.01 software upgrade that includes electric, water, hot water, and beer conservation modes. The great thing about this upgrade is all the conservation modes can be in operation at the same time. The software includes an AI feature to continually optimize its performance and all the modes are user tunable to boot.
I highly recommend it.
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