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This is the STARTING POINT.
Don't be lazy. Choices.
- You have the choice to
start here by checking the air pump pressure....first, or
- You can make the choice
to start throwing parts at your heater, hoping that
one of the parts will find the defect.
But, the REAL FACT is: If
all individual components of the heater are at 100% but the air pump
pressure is not on it's mark, then the heater WILL NOT continue to
run!
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Air Pump Pressure is directly related to
fuel delivery. Read that
statement again! It is the most important line of text on this website.
If the pump
pressure is incorrect, then, the fuel delivery will be incorrect. As a result,
the heater will not run to specs.
Instructions for setting the air pump pressure:
Air pump pressure is
the pulse of the heater. Pump pressures range from 3 psi to 6 psi depending on
heater BTU size (see chart below). A loss of ONLY 1 psi translates to a 30% to
17% loss of FUEL FLOW (starvation). You must know the specified required
pressure and set the pressure accordingly.
Heaters with Hot Surface
Ignitor technology are extremely critical to pump pressure. If the pressure is
off by 1/2 psi, the heater may run for 5
seconds, then shut down
because of IGNITION FAILURE. The only way to correct this problem is to set the
pump pressure to DESA's recommended pressure specification.
- The FIRST STEP in diagnosing any heater problem should
be checking the output of the air pump. Determine the air pressure required for the heater
model that is being tuned. The air pump, in turn, is responsible for
fuel delivery.
- If you do not know the required pressure look for a
decal on the side (usually) of your heater. This decal will state the
model number, serial number, fuel capacity, pump pressure, etc.
- If your plastic end cover looks like this......
 M29609 has 2
threaded holes. The hole on the left has a square plug inserted. Remove the
plug. Screw in the nipple end of the gauge into the threaded hole. Check for
air leaks with soapy water.
or
If your plastic end cover looks like this......
 M16545 has
2 threaded holes. The shorter projection with a hole on the left has a square plug inserted. Remove
the plug. Screw in the nipple end of the gauge into the threaded hole. Check
for air leaks with soapy water.
4. The other hole (longer projection) has a screw with a hole which adjusts a
ball and spring relief valve assembly. Carefully adjust the screw until the
gauge is reading the pressure level that is specified on the heater's label.
If operating properly, the pump should produce more pressure than is
required to operate the heater. The relief valve allows the excess air to
escape before being sent to the nozzle.
5. Replace plug. Test for leak.
6. If you are unable to reach the desired pressure spray
soapy water around the seal of the end cover- at the same time check the
plastic cover for a crack. A cracked end cover will not allow the heater to
perform properly and will not allow for an accurate reading. The pump must
be set at the specified pressure in order to have adequate fuel delivery an
adequate fuel atomization. Replace if needed.
7. If you set the pressure to specs and the heater does
not perform properly or the cone does not glow a soft red, then check for
other fuel delivery problems such as a clogged fuel filter, cracked rubber
hose, clogged or worn nozzle, or a cracked nozzle adapter. Soapy water lightly sprayed in these
areas will quickly identify the problem most of the time. Any air leak
will create problems. |
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 HA1181 air-filled
low pressure gauge. All plumbing included. Ready
to use.
 HA1182 liquid-filled low pressure gauge. All
plumbing included. The advantage of the liquid-filled gauge is the
dampening effect of the liquid while the pump is pulsating. The needle
remains steady. Ready to use.
 
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view the video