Eccotemp L10 Use & Care Manual page 18

If this doesn't clear the air then the tank must be purged.
d. One of the ignition sensors is bent and/or too close to the
burner. Look to ensure that the ignition pins and the heat sensor
are completely vertical and they do a 90 degree to the back of the
box. If they are not straight (i.e. a 45 degree angle) then you can
straighten them with pliers.
e. The thermocouple is either too high or too low to complete the
circuit. Check to ensure that the thermocouple is flush with the
hole in the heat exchanger.
f. The gas sensor wire (looks like a black ground wire on the gas
regulator) flange might have come loose or is no longer
connected.
g. There is a faulty heat or oxygen sensor. This is usually
diagnosed by taking the front case off of the unit and let it run. If it
continues to operate, then one of the sensors and/or the wire
harness needs to be replaced. This may also be caused by
insufficient clearance on the back of the unit where the majority of
air intake is.
h. The valve on the propane tank should be all the way "Open".
i.. Fresh batteries are required for ignition spark. Make sure
batteries are aligned in the proper polarity (+/-).
The water does not get hot enough:
a. You are operating the unit above 6,000 feet / 1820 meters.
While it has been field tested up to 7,200 feet / 2195 meters, we
only recommend using it below elevations of 6,000 feet / 1820
meters.
b. Look into the viewer panes (middle horizontal windows on the
front cover) to see if there is a blue flame. If the flame is yellow
there could be a cracked gas regulator. Do Not Attempt to use the
unit and call Eccotemp directly.
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