The Marey 16L for Natural Gas is one of the least expensive, highest quality, tankless water heaters in its class.
Power goes out in your home? You'll still get hot water, since the 16L gets its ignition from batteries.
The GA16LNGDP saves water while consuming up to 60% less energy than conventional tank water heaters, which makes it cost-effective and environmentally friendly.
• Lasts a lifetime
• Up to 87% energy efficiency
• Rustproof, no leaks, no water loss
• No electrical connection needed: powered by batteries
• Compact design saves space
• Easy installation just about anywhere
• Provides unlimited water
• Produces hot water in mere seconds
• Activates the moment the faucet valve is opened
• 5-year warranty
• Digital LCD display of output water temperature
|Output Capacity||16 LPM / 4.5 GPM|
|Heat Loss||111,903 BTU/h|
|Activation Flow Rate||10 PSI|
|Maximum Flow Rate||4.3 GPM|
|Gas Type||Natural Gas|
|Water Pipe Connection||1/2" NPT|
|Gas Pipe Connection||1/2" NPT|
| Related Gas Pressure (PSI)
||0.25 to 0.5 using natural gas|
|Exhaust Discharge Mode||Flue Duct Type. Vent is 5" diameter.
Use B type (double walled) galvanized pipe or Type III stainless steel pipes.
See venting guide below.
|Applicable Water Pressure||3.6 to 145.0 PSI / 0.25 bar|
|Ignition||2 D cell batteries (not included)|
|DOE Energy Factor (EF Rating)
Regulation 10 CFR 430.32(d) Compliance
|Dimensions||16.5" W x 27.9" H x 8.2" D|
Temperature increase at given hot water flow rates
|Output in GPM|| 0.5
|With highest gas setting (in °F)||-||143||95||71||57||52||48||41||36||33|
|With lowest gas setting||88||44||29||22||18||16||15||13||11||10|
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 16L, 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 16L 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 16L 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 16L produces very hot water. In response, you might turn the cold water tap higher to cool the very hot water. This results in the 16L 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: What are the differences between the 16L and 16L ETL?
A5: The units are similar, but different in many ways.
≈ 16L has a battery ignition. 16L ETL has ignition powered by 110v electrical power cord.
≈ The 16L uses 5" exhaust venting. The 16L ETL uses 3" exhaust venting, and has a separate fresh air intake vent pipe.
≈ The 16L has either standard dial water and gas flow controls on the front of the unit, or an optional digital panel. The 16L ETL uses only a digital panel.
≈ The 16L ETL has the ETL certification, obviously.
≈ The 16L ETL has a higher BTU and a much higher water heating capacity. Please check temperature rise charts.
≈ The 16L ETL weighs more, and various other specs are different.
≈ The 16L ETL has a few new sensors to regulate temperature.
Venting Guide for Marey Heaters
Vent pipe diameters:
5L and 10L: 4"
16L ETL: 3"
Marey includes a coupler with your unit for installation on the 5L, 10L and 16L ETL units. Vent pipe attaches directly to the 16L.
This is not a comprehensive, complete manual. Here is the vent manufacturer's installation manual: Z-Vent Installation and Maintenance Instructions, 3" to 24" diameter, Single & Double Wall. Consult a licensed HVAC professional to install your tankless heater and venting. 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% more expensive. We sell it; the Marey manual specs it.
If you have clearance, this guide will save you a lot of money with single wall pipe.
With both installation types (horizontal and vertical) below, you must have an unlimited supply of fresh air to the room with the 16L. Otherwise, you must install a direct vent system which takes fresh air from the outside.
Notes for through-the-wall installation
First, check out our through-wall, horizontal vent kit for the 16L. It is a 5" vent kit for on-wall tankless installations with horizontal vent direction. This kit provides a discount versus buying all the pieces separately, if you need more pieces that the three shown above.
Note that this kit has no backflow preventer. That's ok 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". Otherwise, see next section below.
"A la carte" individual vent pipe pieces to buy for thru-wall installation for the 16L (GA16NGDP)
↔ If the total pipe length of your horizontal installation is very short, and your installer approves of the use of single wall pipe, then buy the following parts:
● If your wall has combustible materials, then get the 5" Single Wall Thimble.
● If the distance from the back of the 16L, where it would mount and touch the wall to the outside side of the wall, is more than 6.5", then add the appropriate piece of 5" diameter straight pipe (such as 6" or 12" length).
↔ If the total pipe length of your horizontal installation 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-roof installation
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 16L. As always, consult with a professional. Or, use our contractor search link below.
● Universal Adapter w/Backflow Preventer & Condensate Drain, single wall.
● Condensation Drain Tube Kit
● Your choice of a Z-Flex Single Wall 5" diameter pipe length (0.5', 1', 1.5', 2', 3', 4', 5', and Adjustable Pipe up to 18")
● Firestop Spacer
● Firestop Support
● Flat or sloped roof flashing. Choose one:
* Z-Flex 5 inch flat roof flashing
* Z-Flex 5 inch 0 to 30 degree (0/12 to 6/12 pitch) roof flashing
* Z-Flex 5 inch 30 to 45 degree (7/12 to 12/12 pitch) steep pitch roof flashing
● Z-Flex 5 inch rain cap w/wind band
● Z-Flex 5 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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