Reliance Gas Water Heater Won't Light

The Short Answer: A Reliance gas water heater that won’t light usually has no gas reaching it, a missed step in the lighting sequence, an igniter that isn’t sparking, or a clogged air intake. If the status light shows a flash code after an attempt, the control has locked out for a specific reason. Try the label’s lighting instructions once; if the pilot still won’t light or stay lit, call a technician.

Start with the gas supply

Before working on the pilot, confirm gas can get to it:

• The gas valve on the pipe leading to the heater is open (handle parallel to the pipe).
• Other gas appliances, such as the stove or furnace, are working. If none are, the problem is the gas service, not the water heater. See water heater not getting gas.
• On propane, the tank has fuel and its valve is open.
• If the gas was recently shut off, or the heater was just installed or moved, air in the line can delay lighting. Clearing it is a job for the installer or gas technician, not something to do by loosening fittings.

Follow the lighting label exactly

Reliance atmospheric heaters have a lighting label on the front of the heater. The sequence typically involves turning the control to OFF, waiting, setting it to the pilot position, holding the pilot button, and pressing the igniter. Skipping the wait, or releasing the button too soon, is a common reason for failure. If the status light is solid when you start, the manual says the thermopile is still cooling, so wait before relighting.

What happens when you try

Status light codes that block lighting

The Reliance manual lists flash codes on the gas control. Some of them explain why the heater won’t run even when the pilot can be lit:

• 7 flashes: gas control failure.
• 8 flashes: the control detects a flame signal when it shouldn’t, or a pilot valve stuck open.
• 9 flashes: chamber sensor; often linked to restricted combustion air.
• 10 flashes: the heater has detected contaminants in the combustion air (flammable vapor or similar).

Check the label on your heater, since codes can differ between models. A heater in one of these lockouts needs the cause fixed, not repeated relighting. For a light that isn’t blinking at all, see Reliance status light not blinking.

What you can check safely

• Clear lint and dust from the floor around the heater and from the outside of the air-intake screen at the base.
• Move gasoline, paint, solvents, and cleaning chemicals away from the heater.
• Make sure nothing is stored against the heater or blocking airflow in a closet.
• Make one lighting attempt per the label and note exactly what happens.

What the technician will check

A technician will confirm gas pressure at the heater, check the igniter spark and the pilot orifice, and look at the pilot flame and thermopile output. If the status light shows a lockout, they will inspect the flame arrestor and combustion chamber, the chamber sensor, and the venting, then decide whether a sensor or the gas control needs replacing.

Frequently Asked Questions

Q: How many times should I try to light it? A: Follow the label once or twice at most. Repeated attempts can build up gas in the combustion chamber and won’t fix a supply, igniter, or lockout problem.

Q: Can I light a Reliance with a match? A: Only if the lighting label on your heater describes that method. Most current models use a built-in igniter and a sealed combustion chamber, so a match is not an option.

Q: The heater went out after I stored paint thinner nearby. Why won’t it relight? A: Flammable-vapor protection may have shut it down. Remove the source and ventilate the area, then call for service. A tripped flammable-vapor sensor generally needs a technician to inspect and reset or replace it.