There can be many reasons why your Atwood water heater won’t ignite. A blocked main burner orifice, defective igniter, incorrect main burner alignment, or improper air adjustment can be responsible for the issue.
Also, a blocked “U” tube, insufficient gas pressure, bad thermocouple, poor pilot flame, weak gas control magnet, defective E.C.O. in control, and faulty control board can cause your burner to not light up.
Keep reading our Dometic RV water heater troubleshooting guide to solve this issue and get your heater up and running again.
Table Of Contents
- Atwood Water Heater Won’t Ignite [11 Easy Fixes]
- 1. Defective Ignite
- 2. Incorrect Main Burner Alignment
- 3. Improper Air Adjustment
- 4. Blocked “U” Tube
- 5. Insufficient Gas Pressure
- 6. Bad Thermocouple
- 7. Poor Pilot Flame
- 8. Weak Gas Control Magnet
- 9. Defective E.C.O In Control
- 10. Blocked Main Burner Orifice
- 11. Faulty Circuit Board
- Does an Atwood RV water heater have a reset button?
- Can you light an RV water heater with a lighter?
- How do you test an igniter?
- Why is my Atwood water heater not working?
- What do I do if my pilot light won’t light?
Atwood Water Heater Won’t Ignite [11 Easy Fixes]
In this section, we will take a deeper look at the possible causes of why your Atwood water heater won’t ignite and their easy solutions.
Note: You can also read how to fix the Atwood furnace ignition lockout fault problem.
1. Defective Ignite
When your water heater won’t ignite, another possibility is that the igniter is defective. A spark is supposed to erupt from the igniter that lights up the burner. A defective igniter can’t make that happen. As a result, your heater won’t light up.
The easiest way to check whether the igniter is the problem is to see if it sparks when you try to ignite the burner. You will need to remove the access panel and locate the igniter for that.
Take help from the Atwood water heater manual specific to your model. The position of the igniter will vary based on the model.
If your igniter isn’t clicking and producing a spark, you have a problem. Replace the igniter.
2. Incorrect Main Burner Alignment
You may have set up your main burner incorrectly or something could have happened to make it misaligned. This can be why your heater won’t fire.
You need to re-align the main burner with the main burner orifice holder and the gas valve. Also, make sure that the square flame spreader is located at the end of the main burner.
3. Improper Air Adjustment
The air shutter at the main burner needs to be open about a quarter of the way. Otherwise, the water heater won’t get enough combustible air to light up.
This one is pretty easy to solve. All you need to do is to adjust the air shutter to stay open about 1/4th of the way as recommended.
4. Blocked “U” Tube
The “U” tube, also known as the vent pipe or exhaust, is present in all water heaters. What it does is pump burnt fumes from the heater to the outside environment. A blocked venting system can prevent your water heater from igniting.
You need to clean up the pipes to get your heater to ignite. Try using a combination of a metal hook, wet clothes, and a vacuum cleaner to clean out the gunk in there.
5. Insufficient Gas Pressure
The pressure needs to be at least 10” W.C. when read with a U manometer. Otherwise, your heater may not light up due to insufficient gas pressure.
On Atwood pilot model water heaters, only two brands of gas controllers were used; the Robertshaw “Unitrol” and White Rodger.
Both controls include a port for checking gas pressure at the valve. Removing the cover screw and inserting a 1/8″ pipe nipple, can be accomplished.
After you’ve connected your manometer hose to this fitting, while the valve is working, the manometer should read 10″ W.C. Otherwise, call your local gas company for assistance.
6. Bad Thermocouple
The thermocouple is supposed to detect when the pilot flame is on and release gas at the burners for ignition. For models without a pilot, the thermocouple detects the igniter’s spark.
However, when the Atwood water heater thermocouple is not working, your hot water heater won’t fire.
You need to check the thermocouple with the help of a multimeter. When the multimeter is set to the resistance option and connected to the thermocouple, you should get a very small reading that is close to zero.
If the reading is higher, you have a bad thermocouple. Get professional help to replace your thermocouple. You can easily get Atwood water heater parts online.
7. Poor Pilot Flame
The pilot flame can be weak causing your water heater to not light up. Modern water heater models don’t have a pilot. If your water heater is new, chances are, it doesn’t have one. So, this can’t be the issue.
It could be due to a dirty pilot assembly or a defective one. In case you haven’t cleaned up your pilot assembly in months, you need to first try to clean it first.
If that doesn’t solve your problem, you need to replace your pilot assembly.
8. Weak Gas Control Magnet
A lot of the time your water heater’s gas control magnet becomes weak over time which makes the gas control defective. As a result, the water heater doesn’t ignite.
There is no other way to solve this issue other than to replace your heater’s gas control.
9. Defective E.C.O In Control
Defective ECO is also to blame for your water heater’s failure to start. When you turn the switch on and don’t hear the gas valve click, you know it’s for the ECO.
The ECO switch connects the gas valve to the control board. It also has a connection to the thermostat. If it fails, no power will be supplied to the gas valve, making your water heater not ignite.
To begin, remove one of the ECO’s wires and use a VOM to check for continuity. Check to see if the meter reads 12 volts. A short circuit should be present.
It’s time to change the new ECO if it doesn’t show the precise volt. Also, because the manufacturer offers them as a pair, you need to get a replacement thermostat.
10. Blocked Main Burner Orifice
Built-up soot from incomplete combustion, dirt, or debris can cause your heater’s burner orifice to get dirty and blocked up. A clogged burner orifice can be behind your Atwood water heater clicking but not lighting.
You need to clean the burner assembly of your Atwood water heater. For that, the first thing you need to ensure is that the heater’s power and gas supply have been shut down.
The whole process is plenty complicated. So, if you are a novice at water heater repairs, don’t try to do it yourself. Hire a professional.
11. Faulty Circuit Board
Atwood RV heaters have a bad rep when it comes to circuit boards. The design of their control board makes it prone to damage.
It is possible that your heater’s control board is faulty causing your heater to not ignite.
We recommend you call Atwood for a replacement control board after ensuring that the control board is faulty. You can check with the help of a multimeter. A bad control board may appear fried or burnt as well.
Well, watching the video will be helpful for you to get more information.
Does an Atwood RV water heater have a reset button?
Yes. In most models, the reset button is located near the heating element. Red in color, the reset button protrudes out if the device has to be reset.
Can you light an RV water heater with a lighter?
If you have an older version of a water heater featuring a pilot light, yes. For modern models that have an igniter instead, you don’t need a lighter. Ignition is fully automatic.
How do you test an igniter?
You can test the ignitor with a multimeter. When set to the lowest possible resistance and then connected to the igniter, the multimeter getting a reading of zero or infinity means the igniter is bad.
Why is my Atwood water heater not working?
A pilot outage is one of the most typical issues with Atwood RV water heaters. If your gas control magnet is weak or your thermocouple has to be replaced, this can happen. You’ll need to change the orifice if the pilot flame isn’t working properly.
What do I do if my pilot light won’t light?
It’s possible that the thermocouple is to blame for your pilot light not staying lit. Cleaning the thermocouple and relighting the pilot light are two options. Try replacing the thermocouple if the problem persists.
Hopefully, now you know why your Atwood water heater won’t ignite and what to do to simply solve each issue. Finally, you will have your RV heater running in no time.
You just need to have a bit of patience to go through each possible cause. If still you have any quires, the comment box is free for you.