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Marey 100K BTU 3.7 GPM Nat. Gas Tankless Water Heater GA14CSANG

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Original price $469.99 - Original price $479.94
Original price
$469.99 - $479.94
Current price $469.99


Marey Tankless Water Heaters

The one tankless water heater that checks all the boxes:
√ 100,000 BTU powerful. Good for whole home and multiple, simultaneous points of use.
√ Natural gas fuel
√ CSA approved for USA and Canada
√ Less expensive than comparable heaters
√ Built-in anti-freeze system

More great features

• Digital, touchscreen controls including precise temperature setting
• Rustproof, no leaks, no water loss
• Compact design saves space
• Advanced safety system:
- boil-dry, over-heating protection
- flame failure protection
- anti-freeze function automatically starts at temperatures between 37°F and 46°F, when 120V electrical current is on.
• Electronic ignition. No pilot light saves gas and uses no gas when not actively heating water.
• Activates the moment the faucet is opened and water is flowing
• Copper heat exchanger has oxygen-free design
• Warranty on heat exchanger: 5 year. Warranty on parts: 5 years. No labor warranty.

Technical Specifications

Installation type Indoor
Flue pipe connection diameter 3 inches
Temperature Increase Capacity
35°F increase at a flow rate of 4.6 GPM
55°F increase at a flow rate of 2.9 GPM

Gas: 1/2 inch NPT
Cold Water Supply: 1/2 inch NPT
Hot Water Supply: 1/2 inch NPT

Activation Flow Rate 0.65 GPM (2.5 L/min)
Minimum Sustained Flow Rate 0.53 GPM (2.0 L/min)
Applicable Water Pressure 15 PSI minimum to 150 PSI
Gas Type Natural Gas
Max./Min. Gas Consumption 100,000 BTU/h to 20,000 BTU/h
Related Gas Pressure (PSI)
Rated gas pressure 7.0 inch W.C. (1.74 kPa)
Ignition Direct electronic ignition
DOE Energy Factor (EF Rating)
Regulation 10 CFR 430.32(d) Compliance
Dimensions 13.9" W x 25.9" H x 5.6" D
Weight 33 lbs (15 kg)
Factory set output temperature option

107°F (42°C)

Available temperature settings

95°F to 140°F (35°C to 60°C)

Water temperature control Input and output water temperature signals
Water flow control Electronic Water flow sensor
Electrical supply 120V cord with 3-prong plug. 60Hz
Electrical Consumption
(Freeze protection)
100W, 0.85 amps
Electrical Consumption (Stand-by) 3W, 0.15 amps
Certifications Marey GA24CSANG is CSA certified

Marey GA14CSANG forced air Tankless Water Heater

Included in the box

  • heater
  • manual
  • pipe fittings

Not included but required
- 150 PSI pressure relief valve
- 3" diameter exhaust vent pipe (See guide below.)

Pipe connection/installation

We recommend making the cold water inlet, hot water outlet and the gas fitting connections from your hard lines to the unit using flexible appliance hoses (e.g., push-connect, Shark Bite fittings).

Venting Guide for Marey Heaters

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

There is a 3" diameter vent opening at the top of the unit. NEVER restrict venting down to a smaller size.

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 to combustible materials. Double wall must have only 6" clearance. (Always verify with local building code.) Stainless steel pipe is an expensive material. Double that amount in one pipe with double wall, so note that it is more expensive. It is available here on

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

Notes for through wall installation. Links to the parts are in the text and blue Related Gadgets tab above.

Marey includes a coupler that slides onto the top of the flue of the GA14CSANG. Next...

↔ If the total pipe length of your horizontal venting installation is very short, then buy the following parts:

Z-Flex 3" Universal Appliance Adapter
3" Single Wall 90 Degree Elbow
3" Termination Hood with Backflow Preventer

→ Options:

● If the distance from the back of the GA14CSANG, where it would mount and touch the wall to the outside side of the wall, is more than 4.5", then add the appropriate piece of 3" diameter straight pipe (such as the 6" or 12" length).

● Does the room have an unlimited supply of free-flowing fresh air? If so, the parts above are all you need (but verified by a licensed professional). If not, then vent in fresh air from outdoors using a few feet (depending on your installation) of 1 Ply Flexible Aluminum Duct, 3".

● Does the wall that you are going through contain combustible materials? If so, add 3" Wall Thimble.

● Is the total pipe length longer than 5 feet? Then add a condensation drain pipe section.

↔ 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 pipe.

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. Cut 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 parallel with the wall. Secure the piping with galvanized steel brackets or clamps. On top of the second piece of exhaust pipe, attach the rain/wind cap. Attach a condensation drain on the portion of pipe located outside the structure.

Notes for through the roof installation. Links to the parts are in the text and blue Related Gadgets tab above.

Marey includes a coupler that slides onto the top of the flue of the GA14CSANG. Next...

Buy one piece of straight pipe no longer than 60", plus a wind/rain cap, plus a condensation drain.

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 GA14CSANG. As always, consult with a professional. Or, use our contractor referral link below.

Z-Flex 3" Universal Appliance Adapter with Backflow Preventer
● Your choice of your installation's height/length of Z-Flex Pipe 3" diameter pipe. If you are not sure of the exact length up to 18", choose the Adjustable 18" Pipe on that page.
Z-Flex Flat roof flashing
Z-Flex 0 to 30 degree pitch roof flashing
Z-Flex Storm collar
Z-Flex Rain cap with wind band

● Does the room have an unlimited supply of free-flowing fresh air? If so, the parts above are all you need (after consulting a licensed professional). If not, add a fresh air intake from outdoors using a length of 1 Ply Flexible Aluminum Duct, 3".

Frequently Asked Question (FAQ)


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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