Marey Gas Tankless Water Heater Not Igniting
On this page (5 sections)
The Short Answer: Marey’s smaller gas units (GA5 and GA10) light only when enough water flows through them and use two D-cell batteries for the spark. Weak batteries, low water pressure or flow, a closed gas valve, an empty propane tank, or air in the gas line are the usual reasons they won’t light. On the plug-in GA16ETL, an E2 code means the flame wasn’t detected. A gas smell means stop and leave.
Which Marey do you have?
Marey sells gas and electric tankless heaters under similar names. Only the gas models have a burner to light.
| Model type | How it ignites | Display codes |
|---|---|---|
| Gas 5 & 10 Flow (GA5FLP/GA5FNG, GA10FLP/GA10FNG), sometimes sold as “Power Gas” | Spark powered by two D-cell batteries when water flows | No digital codes; knobs for water, gas and winter/summer |
| GA16ETL and similar plug-in models | Electronic ignition with a combustion fan, 120-volt power | E-codes on the display |
| Electric tankless (ECO series and similar) | No burner; heating elements | Not covered here; see electric tankless goes cold |
Every Marey gas model has a flue connection, and its manual requires exhaust venting. The GA5/GA10 manual calls for double-wall Category I venting (B-vent or Z-vent; 4-inch for the GA5), forbids installation in a sealed or poorly ventilated room, and requires a carbon monoxide detector. The GA16ETL manual says it is for indoor mounting only and must not be operated without its vent pipe connected. Any portable propane water heater without a vent connection, from any brand, is an outdoor appliance only. Never use one indoors, in an RV, in a tent, or in any enclosed space.
GA5 and GA10: no click, or clicks but no flame
These units start only when water flowing through them pushes on a water-control diaphragm and switches on the igniter. Marey’s manual says they need about 2 to 2.9 psi of water pressure to fire. It also says not to use them below 8 psi or below the flow listed for your model.
No clicking at all usually means:
- Batteries are weak, dead or in backward. Fit two fresh D cells, checking the polarity diagram on the battery compartment.
- Not enough water is flowing through the unit. Open the hot tap fully. Low house pressure, a partly closed valve, or a clogged faucet aerator or shower head can keep flow below the starting point. The water inlet has a filter screen that can clog with debris. The manual covers cleaning it with the water shut off.
- The hot and cold connections are reversed, which happens on new installs.
Clicking but no flame usually means:
- The gas valve is closed or only partly open, or the propane tank is empty. Marey’s troubleshooting chart lists these first.
- There is air in the gas line after a new install or a propane tank change. Marey’s manual says to turn the hot water on and off several times until the burner lights. Only do this if there is no gas smell, and stop if it doesn’t light after a few tries.
- Gas pressure is wrong for the unit, or the propane regulator isn’t suitable. That needs a technician.
- The igniter gap or electrode is off position or wet.
Lights, then goes out: too little water flow (the overheat protection shuts it down), low gas pressure, wind blowing down the flue, or poor air supply. Marey tells owners to keep the unit out of strong wind and rain.
GA16ETL: what the display codes mean
These are from the GA16ETL manual. Other Marey electronic models may use different codes, so check the manual for the model on your rating plate.
| Code | Marey’s description | What it usually means for you |
|---|---|---|
| E0 | Blower system problem | The fan isn’t running properly. Don’t run the unit. |
| E1 | Outlet water temperature sensor error | Sensor or connection fault, not an ignition failure |
| E2 | Flame detection error | Didn’t light or flame went out: gas supply, air in line, igniter, wrong gas type |
| E3 | Inlet water temperature sensor problem | Sensor or connection fault |
| E4 | High temperature automatic shutdown | Water above 185°F for 10 seconds, often from a sudden drop in flow |
| E5 | Overheating occurred | Long heavy use then a sudden change; check gas and water supply if frequent |
| E6 | Solenoid valve error | Gas valve or its wiring |
| E8 | Exhaust system error | Blocked or overlong vent, or air pressure switch |
The GA16ETL manual lists an activation flow of 0.67 gallons per minute. The unit keeps running until flow drops below 0.53 gpm. If the unit never tries to light, check that a faucet is fully open before anything else.
For an E2, Marey’s suggested checks include the gas supply, especially right after installation when air may be in the line, and whether the gas type matches the rating plate. An LP unit on natural gas, or the reverse, won’t run correctly and must not be modified by the owner. Repeated E2 codes, or any E0, E6 or E8, need a qualified technician.
What the technician will check
A gas technician will check inlet gas pressure and the regulator against the rating plate, confirm the gas type matches, and inspect the igniter, flame sensor and gas valve. They also check the venting against the manual’s requirements, look for a blocked flue or backdraft, and confirm water pressure and flow at the unit. Gas conversions and gas fitting work are their job, not the owner’s.
Frequently Asked Questions
Q: My Marey clicks but won’t light after I changed the propane tank. What now? A: Air in the line is common after a tank change. Marey’s manual says to open and close the hot water several times until it lights. If you smell gas, or it still won’t light after a few tries, stop and have the regulator and connections checked.
Q: Why does my Marey only light when I open the tap all the way? A: These units need a minimum flow to start, and low-flow shower heads or low house pressure can fall below it. Clean the inlet filter and aerators. If house pressure is low, a plumber can measure it.
Q: Can I use a Marey gas tankless in a camper or shed without a vent? A: No. Marey’s gas models are designed to be vented to the outside, with a CO detector nearby. Running any gas water heater unvented in an enclosed space can cause carbon monoxide poisoning.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Marey Gas 5 & 10 Flow instruction manual (GA5FLP, GA5FNG, GA10FLP, GA10FNG) (opens in a new tab)Battery-ignition Marey Gas Flow / Power Gas GA5 and GA10 models: water pressure, venting and troubleshooting chart.
- Marey GA16ETL gas tankless water heater manual (opens in a new tab)Marey GA16ETL indoor, fan-vented model: activation flow, diagnostic codes E0 to E8.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
- CPSC: carbon monoxide fact sheet (opens in a new tab)Carbon monoxide hazards and emergency response.
Editorial standards and corrections · Prepare a useful service request