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Marey 10L Indoor Natural Gas Tankless Water Heater

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Original price $269.00 - Original price $269.00
Original price
$269.00 - $269.00
Current price $269.00


Marey 10L Outdoor LP Tankless Water HeaterBuy this Leading and Reliable Indoor NG Tankless Water Heater: Marey 10L

Install it anywhere, because you don't need an electrical connection. The ignition is battery-powered. Popular uses are for RV, food trucks, remote backwoods cabin, pool and poolhouse shower, barn, dog kennel.

This on-demand hot water heater is so small, it can fit in a suitcase: It is less than two feet tall. So, you can install it just about anywhere. You will save a lot of space compared to a tank water heater.

Because it is tankless, the 10L will heat an unlimited volume of water. No more running out of hot water on a cold day.

Since the 10L starts heating water when you turn on the hot water faucet, it uses energy only when you use it.

The Marey 10L is built to last a lifetime from a company in business for a lifetime, since 1955.

The 10L tankless heater is rustproof. You can forget about water leaks.

Environmentally friendly and inexpensive to operate: This water heater saves water. Plus it uses up to 60% less energy than a conventional tank water heater.

• Optional digital panel display shows output temperature


Energy Source Natural Gas
BTU Heat Capacity 79,228 BTU per hour
Minimum Water Flow Rate for Heater Activation 10 PSI
Maximum Water Flow Rate 3.1 GPM
Gas inlet joint 1/2" NPT pipe thread
Cold water inlet and hot water outlet joints 1/2" NPT pipe thread
Required Gas Pressure 0.4 PSI
Exhaust Type

Flue Duct; Vent is 4" diameter. Use B type galvanized pipe or Type III stainless steel pipes.

Water Pressure Range 3.6 to 145 PSI (0.25 to 10 bars)
Ignition Method Two "D" Cell Batteries (not included)
DOE Energy Factor (EF Rating) Regulation 10 CFR 430.32(d) Compliance 0.85
Dimensions in inches (H x W x D) 23.6 x 13.6 x 6.9
Weight 21 lbs
Warranty 5 years on Parts, 1 year on Labor

Marey 10L Outdoor LP Tankless Water Heater

Temperature Rise Table

Gas Flow Setting 0.5 GPM 1.0 GPM 1.5 GPM 2.0 GPM 2.5 GPM 2.7 GPM 3.0 GPM
Highest - 100°F 67°F 50°F 40°F 37°F 30°F
Lowest 68°F 34°F 23°F 17°F 14°F 13°F 9°F

In some climates, users of the 10L use the "Highest" setting for Winter and the "Lowest" setting for summer.

10L User Manual
10L Installation Video

Frequently Asked Questions ("FAQ")

Q1: Is there a max water temperature at the inlet connection? Would like a backup for solar water storage.

A1: There is no maximum incoming water temperature for the 10L, above which the heater will not fire. However, Marey recommends that the incoming water temperature not exceed 120°F, since such temperatures could damage the rubber diaphragm.

Q2: I've heard that the Marey 10L goes from hot to cold during use, and makes a lot of people dissatisfied with this unit. Is that true?
or Q2: I turned on the hot water handle. Hot water comes out. Then I turned on the cold water and the hot water stopped coming out.
A2: Often people do not take the time to learn how to use the unit. When trying to get the hot water to flow, they make extreme changes to the knob positions which are not correct, and lose patience. Here is how to get a steady, continuous heated output temperature:

The 10L has three control knobs: one for water temperature, one for a winter or summer setting, and one for water flow rate. Start with these settings:
- water flow rate knob (on the bottom right) at the lowest setting
- winter/summer setting to winter.
- water temperature knob (on the bottom left) on the highest setting (far right position)
With these settings the 10L produces very hot water. In response, you might turn the cold water tap higher to cool the very hot water. This results in the 10L stopping the burner, and the shower water temperature will change to cold.
To solve this problem, simply turn the water temperature knob (on the bottom left) down in small increments, until the shower water remains at a comfortable temperature, continuously. Make only a few small adjustments, until you find the perfect setting. With the change of seasons, as the incoming water temperature rises and falls, you will need to make small adjustments again.

Q3: How often do the batteries need to be replaced?
A3: You may find that the batteries will last three to six months if you use multiple showers or sinks per day. If you use the heater about once per day, the batteries may last about one year.

Q4: Will this heater work if I have 3/4" water pipes?
A4: Yes, if you have existing 3/4" pipe, you can use a common adapter fitting on the heater to change from 3/4" to 1/2".

Q5: Will the 10L work at an elevation of 3000 feet above sea level?
A5: Yes, it should operate at altitudes above 3000 feet. However, there will be an efficiency loss of ~10% per 1000 feet of elevation. Therefore, if you are at high altitudes, then consider the larger 16L with more BTU's. Although the manual does not mention an elevation limitation, some customers have told us the 10L works fine at 10,000 feet.

Venting Guide for Marey Heaters

Marey 10L Indoor LP/NG Tankless Water Heater

This is not a comprehensive, complete manual. Consult a licensed HVAC professional to install your tankless heater. Find a professional here.

Selecting the correct vent type: Stainless or galvanized?

The condensation of a tankless water heater is slightly more acidic and thus corrosive than a standard water heater's condensation. That is why many building codes in North America require Type III stainless steel, such as Z-Vent shown in the blue Related Gadgets tab above, for venting natural gas and propane tankless hot water heaters. It will never corrode or rust.

Alternatively, some building codes in North America allow for B-vent to be used. B-vent is double walled galvanized vent pipe made for standard water heaters and stove vent pipe. Unfortunately, the less expensive B-vent material will eventually corrode. This would allow dangerous fumes to leak into the space. If you are considering B-vent pipe you must check your local building codes to see if it is allowed. If you do an installation with B-Vent, you must inspect the pipe at least once per month for corrosion, and immediately replace any corroding ones. It's likely that the B-vent pipe will be corroded within 5 years.

Single wall or Double wall?

Single wall pipe gets very hot and typically must have 18" clearance. Double wall must have only 6" clearance. (Always verify with local code.) Stainless steel pipe is an expensive material. Double that amount in one pipe with double wall. Double wall has lot of high-grade steel, and it's 50% moreexpensive. We sell it; the Marey manual specs it.

If you have clearance, we are saving you a lot of money by providing the single wall pipe.

With both installations below, you must have an unlimited supply of fresh air to the room with the 10L. Otherwise, you must install a direct vent system which takes fresh air from the outside.

Through-wall, horizontal vent kits for the 10L

Without backflow preventer: Use this one if there is no chance that freezing air could enter into the heater through the vent pipes, and you have a wall thickness less than 7".

With backflow preventer: Use this one if freezing air could enter into the heater through the vent pipes, and you have a wall thickness less than 7".

"A la carte" individual vent pipe pieces to buy for through-wall installation

Use the supplied coupler that ships with the 10L. Next...

↔ If the total pipe length of your horizontal installation is short enough to prevent condensation, and your installer approves of the use of single wall pipe, then buy the following parts:

Z-Flex Z-Vent 4" Universal Appliance Adapter With Back-Flow Preventer
Z-Flex Z-Vent 4" 90° Elbow Single Wall
Z-Flex Z-Vent 4" Single Wall Termination Coupling

That's all! Total venting cost can be less than $150. You do not need a condensation drain pipe section because of the short pipe run.

Options for other installation situations:
● If your wall has combustible materials, then buy the 4" Single Wall Thimble.
● If the distance from the back of the 10L, to the outdoors side of the wall, is more than 5.5", or the wall is combustible, then add the appropriate piece of 4" straight pipe (such as 6" or 12" length).
● Is the total pipe length longer than 5'? Then replace the Universal Appliance Adapter ("UAA") above with a UAA with condensate drain.

If the total pipe length of your horizontal installation is requires some vertical distance outside, then follow these instructions:

Buy two 45° elbows, plus one straight pipe no longer than 18" in length, plus one straight pipe no longer than 42" in length, plus one wind/rain cap, plus one condensation drain.

From the flue collar at the top of the water heater, attach the first 45° elbow with a vent pipe coupler. After the elbow is attached, use it as a template for cutting the hole through the wall at a 45° upward angle, with a slightly larger diameter than the pipe. Attach an 18" piece of straight pipe to the 45° elbow and insert through the hole in the wall. If your wall is more than 18" thick, use a longer pipe up to 24" and reduce the length of the second pipe to 36". Do not exceed 60" for the total vent length, unless you use a low CFM duct booster fan to ensure proper venting of the heater.

On the other side of the wall, attach the second 45° elbow so that the second pipe will run vertically, parallel with the wall. Secure the piping with galvanized steel brackets or clamps. Attach a condensation drain pipe piece on the portion of pipe located outside the structure. On top of the second piece of exhaust pipe, attach the rain/wind cap.

Notes for through the roof installation

Use the supplied coupler that ships with the 10L. Next...

Drill a hole through the ceiling and roof that is slightly larger than the vent pipe diameter. Attach the pipe to the top of the unit and go straight up and out the roof. On the roof, attach to the vent pipe a rain/wind cap. The total vertical distance from heater to rain/wind cap must not exceed 60", unless you use a low CFM duct booster fan to ensure proper venting of the heater. Roof clearance must be at least 12".

The area around the fresh air intake of the heater must be no less than 0.75 square feet (or about 9" x 12").

Below are the venting products you may need for vertical venting through the roof for the Marey 5L and 10L. As always, consult with a professional. Or, use our contractor link below.

Universal Adapter w/Backflow Preventer & Condensate Drain, single wall.
Condensation Drain Tube Kit
● Your choice of a Z-Flex Single Wall 4" diameter pipe length (0.5', 1', 1.5', 2', 3', 4', 5', and Adjustable Pipe up to 18")
● Flat or sloped roof flashing. Choose one:
* Z-Flex 4 inch flat roof flashing
* Z-Flex 4 inch 0 to 30 degree (0/12 to 6/12 pitch) roof flashing
* Z-Flex 4 inch 30 to 45 degree (7/12 to 12/12 pitch) pitch roof flashing
Z-Flex 4 inch rain cap w/wind band
Z-Flex 4 inch Storm Collar

Installation Help and Recommendations

We recommend that you have a professional tankless water heater installer review the above recommendations. Need an installer? Get 4 FREE Tankless Water Heater Installation Estimates Now. It's Quick and Easy!
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