Water pressure for tankless heater

centerline · Nov 24, 2014

mtenzer said:
Hi All. I have a sailboat and my fresh water system includes a jabsco automatic pump with max 40 psi and an accumulator tank. I recently installed an on demand tankless propane water heater in my shower. The problem is that it cuts out as the pressure drops. If the pump has just primed, it triggers ignition of the heater. As the pressure drops, the gas cuts off at some point.
Is there a way to reset the low pressure
cut- on point of the pump or increase the pressure at the accumulator?
Thanks,
Mike

providing the pump is working correctly and the accumulator is not flat (lost its charge pressure), if you are using one of the variable pressure/flow pumps, they dont work well with the on demand water heaters.... In my trailer, i had to get rid of the high dollar sureflo pump and went with an old fashioned impeller pump (sureflo) and it works fine.

im not sure about adjusting the pressure on the variable pumps, but the old style of pumps has that option and is easy as turning a screw at the pump head.

Maine Sail · Nov 24, 2014

mtenzer said:
Hi All. I have a sailboat and my fresh water system includes a jabsco automatic pump with max 40 psi and an accumulator tank. I recently installed an on demand tankless propane water heater in my shower. The problem is that it cuts out as the pressure drops. If the pump has just primed, it triggers ignition of the heater. As the pressure drops, the gas cuts off at some point.
Is there a way to reset the low pressure
cut- on point of the pump or increase the pressure at the accumulator?
Thanks,
Mike

You may need a higher PSI pump..

You may also want to check with your insurer as there are currently no on-demand tankless propane water heaters that meet the minimum marine safety standards, which your insurance company is expecting to insure your boat to..

Maine Sail · Nov 24, 2014

mtenzer said:
Thanks for the reply. I wonder if the higher psi pumps have a higher "cut on" pressure? It's not the peak pressure that's a problem but the pressure drop before the pump re-starts

Yes they have a higher cut in. Depending upon brand there is an approx 15-20 PSI difference between on & off. I use a high pressure pump on our boat and the difference did what I needed..

Benny17441 · Nov 24, 2014

I don't think there is a need to contact your insurance company and perhaps trigger a request for a survey. They love to have someone tell them in writing and at your expense of things that need fixing or should not be installed on the boat. If in doubt check your insurance policy for exclusions to see if tankless water heaters are listed. I doubt it. If this is one of those heaters fed by 1lb canisters I would not worry as you can disconnect the canister after use, but if you are tapping in to the boat's delivery lines I would strongly recommend you install a shut off switch so you do not have to rely on the unit's built in switch .

mitiempo · Nov 24, 2014

Benny17441 said:
I don't think there is a need to contact your insurance company and perhaps trigger a request for a survey. They love to have someone tell them in writing and at your expense of things that need fixing or should not be installed on the boat. If in doubt check your insurance policy for exclusions to see if tankless water heaters are listed. I doubt it.

That is bad advice. To meet ABYC a tankless water heater must be ventilated, have a closed combustion chamber, and not have a pilot light. Surveyors and insurance companies abide by ABYC. If there is a claim relating to the water heater expect no payment from insurance. Mainesail has removed these units from boats as they will not pass a survey with them, and therefore are unable to insure.

Not to mention the deaths from CO if installed in an un-ventilated shower area.

thinwater · Nov 25, 2014

Maine Sail said:
You may need a higher PSI pump..

You may also want to check with your insurer as there are currently no on-demand tankless propane water heaters that meet the minimum marine safety standards, which your insurance company is expecting to insure your boat to..

Could you specify which requirements? My boat has one that has been through at least 4 surveys. My understanding, from the factory paperwork, is that it was factory installed. It is vented w/water tight stack, has leak sensors, and is in a bulk headed compartment with low-level gas ventalation. Everything about the installation looks factory, down to using exactly the same plumbing and mounting methods that were used throughout.

The manufacturer is Takagi, though the specific model is out of production. 1997.

Benny17441 · Nov 25, 2014

Mitiempo, that is precisely the reasons why I would try to avoid a survey. Insurance policies are governed by the coverage agreement and if there is no mention of a type of water heater being excluded from coverage it is unlikely that the insurer would not pay a claim. Like Maine has said many times, more and more surveyors are applying the ABYC guidelines to their reports and the insurers then require their customers to comply. Understand that surveys and coverage agreements are never up to date to the ABYC standarts. My survey is circa 2001 and do not see any exclusions that would negate coverage in my current policyfor the use of a tankless water heater. Besides this, the main issue is safety and I believe I addressed some installation and procedure concerns. I'm sorry if you considered my comments as bad advice but I will let the readers judge for themselves.
Comprende?

mitiempo · Nov 25, 2014

If you forever avoid a survey you ultimately are not insurable. There are 2 main issues - safety and insurer liability. There are numerous cases of surveyors requiring removal of these type of water heaters. Without their removal per survey you cannot insure. Insurance companies do listen to surveyors. Insurance policies do not list all exclusions but they love having a reason not to pay.

Benny17441 · Nov 25, 2014

Mitiempo, I'm sorry but you are saying things that do not make sense. An insurance policy is a contract and coverages and exclusions must be listed and they will define in a court of law if necessary the obligation or not to pay a claim, not whether they like or not. I know I cannot avoid a survey forever but why call for one? In case you misunderstand the ABYC standards they are promulgated by a non-government association to provide guidelines to manufacturers for new boat construction. It has indeed been a trend for most licensed surveyors to adopt some of the guidelines that pertain to safety in their observations. Once a survey report is submitted to an insurer an underwriter will determine the risk posed by any observation and determine if they will incorporate an exclusion of coverage for that observation. Insurers rely on many other indicators to determine their risk and as such determine the frequency in which they may require new surveys. The policies are usually contracted yearly in which they may include any new exclusions from coverage they may deem necessary. Understand a survey does not force a boat owner to remove anything, it is the insurance underwriter that will give you the hard choice to remove something or loose coverage. Not all deficiencies noted in a survey will trigger an insurance exclusion. I always advocate to treat your insurer with utmost respect and accede to whatever they may ask. I do not perform changes or will be quick to make upgrades when safety is in question and have never had to make changes as a consequence of a new survey. I consider myself to be fairly well versed in boat systems and well educated in insurance matters and I sincerely fail to understand some of your statements.

Maine Sail · Nov 25, 2014

thinwater said:
Could you specify which requirements? My boat has one that has been through at least 4 surveys. My understanding, from the factory paperwork, is that it was factory installed. It is vented w/water tight stack, has leak sensors, and is in a bulk headed compartment with low-level gas ventalation. Everything about the installation looks factory, down to using exactly the same plumbing and mounting methods that were used throughout.

The manufacturer is Takagi, though the specific model is out of production. 1997.

You've been lucky or had surveyors who simply look the other way or just don't know their stuff.. Factory installed does not mean much of anything as there are many boats not built to ABYC standards and many ABYC built boats that flagrantly miss items that are required..

All that matters is what is in the survey report. If your surveyors have missed it, and you like your water heater, USE THEM AGAIN!!

To be ABYC compliant the water heater must be 100% room sealed combustion. Make up air must come from outside the vessel and combustion air must vent outside the vessel. Water heaters are classified under ABYC standards as an unattended appliance and thus need to meet the standards for an unattended appliance.

As of yet I don't know of any on-demand LPG heater that meets the standard, though many companies lie and purposely deceive buyers...

Some considerations from the ABYC 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.

Having been on the receiving end of an on demand LPG heater removal, on a customers boat, which was mandated after an insurance survey, I really do feel for the folks who buy these products from sleazy misleading companies. Sadly these companies know damn well these water heaters do not meet marine safety standards but they mislead the consumer anyway...

Course it is not just water heaters. I know I have posted this before but here it is again:

FACT: You as a private boater do NOT need to comply with the ABYC standards

Catch 22 / CAUSE FOR CONSIDERATION: Your surveyor surveys to ABYC standards and your insurance company underwrites your boat based on the surveyors report! If you happen to have one that misses deficiencies then that is likely less costly for you....

These are just a bit of the "insurance/survey" items I have had to deal with over the last few years:

*Bond a keel stepped mast to external ballast (after a strike claim this is not even a standard)
*Bond numerous boats for AC Grounding to DC Grounding
*Add over current protection where it did not exist (house banks for example)
*2 Boats for the AC inlet / breaker 10' rule
*1 Boat for an improper AC main breaker (not double pole)
*Multiple boats for GFCI outlets
*Multiple boats for lack of DC over-current protection
*Multiple boats for LPG system issues
*1 Boat for AC/DC isolation (cover for AC) behind AC/DC panel
*Multiple boats for fuel system issues (too many to list)
*1 Boat for a reverse polarity indicator
*Approx three boats for non compliant battery chargers
*2 Boats for ignition protection issues on gas boats.
*1 Boat for lack of a bilge blower
*Improper bonding of chargers and inverter/chargers
*1 Boat for a bilge pump alarm
*Multiple boats for deteriorated below waterline hoses
*Remove a non compliant on-demand water heater (Excel)
*Multiple battery system compliance issues including venting, acid containment, over current protection etc..
*Multiple unsafe termination issues (solder, wire nuts, improper lug stacking etc.)
*Steering system failures (meat hooks etc.)

There are probably more that I am just forgetting... Insurance companies and surveyors today are playing a CYA game. Surveyors are indeed getting better and have more training in ABYC, CFR and other standards than ever before.

In today's day and age it does pay to use the available safety standards as a solid guideline for boat upgrades (see list above). The survey industry uses the standards so the closer your boat is to those guidelines (ABYC) the better chance you will have a skating through clean on an insurance survey. LPG systems are but one of the hot ticket items but electrical is getting more and more demanding I suppose because 55% of boat fires are electrical in nature...

mitiempo · Nov 25, 2014

Benny17441 said:
Mitiempo, I'm sorry but you are saying things that do not make sense. An insurance policy is a contract and coverages and exclusions must be listed and they will define in a court of law if necessary the obligation or not to pay a claim, not whether they like or not. I know I cannot avoid a survey forever but why call for one.

You are forgetting one important item. If a surveyor flags a specific item - water heater, wiring issue or whatever - the insurer will not insure without the recommendation being carried out. IF you state the offending item is removed or fixed and it is not they do not have to pay a claim arising from said item. The exclusions do not have to be listed because if they are found by a surveyor that knows his stuff (ABYC) the boat will not be insured as is anyway.

You may not want a survey but your insurer will one day.

thinwater · Nov 25, 2014

Because the heater is in a bulkheaded compartment, (water-tight, keel to deck) many of the requirements don't apply. The rest seem to be met by design or installation. I don't see how this is impossible.

But Ican see it required considerable effort, and that most retrofits would fail major items.

Thanks for the details.

Water pressure for tankless heater

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