Heat Sources; Temperature & Pressure; Low Lp Gas Pressure; Test Each Heat Source - ARP Fridge Defend Troubleshooting Manual

ARP Control v5.x Troubleshooting Guide
SPAR. The ARP cannot determine the cause
of the abnormality. This is the responsibility
of the operator. Other than off-level operation
of the SPAR, and boiler over heating due to
wind currents that result in stagnation within
the cooling unit compartment, it is beyond
the scope of this document to cover all of the
causes for the SPAR boiler to overheat.
In the following sections of the
Troubleshooting Guide are suggestions to
help you resolve situations that may arise.
Again, it is the operator's responsibility to
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HEAT SOURCES

5.1 Temperature & Pressure
The boiler temperature is an over all indicator
of your refrigerator health. It is advised to
check and adjust your LP gas pressure,
check your gas flame and adjust if necessary.
Only then record your 'normal' boiler
temperatures using both LP gas and the
electric heat source for future troubleshooting
reference. Please note, for the following
discussion, the LP gas temperature
measured by the ARP is generally about
10°C (18°F) higher than the temperature
measured by the 120VAC. A rule of thumb is
that the LP gas temperature will range from
170°C (338°F) to 190°C (374°F) depending
on the make and model of your SPAR. The
boiler temperature can vary with the RTD
location on the boiler tube also.
There are few causes of low boiler
temperature, low LP gas pressure, failed
electric heaters, and low cooling unit
pressure. Low cooling unit pressure is
covered in section 6.1.

SPAR PRESSURE

6.1 Low Cooling Unit Pressure

The temperature at which a liquid changes
phase from liquid to gas (boils) is dependent
on two physical qualities: temperature and
pressure. The temperature measured at your
boiler is dependent upon your cooling unit
pressure. If the pressure inside your cooling
04/20/202 0 © 2013-2020 ARPC L.L.C. All rights reserved.
insure that safe operation of the SPAR is in
effect. Although the ARP can give an
operator feedback, the operator must have
discretion to make decisions responsibly and
act on one's own. If there is doubt, please
take your RV to a qualified RV service center.
Following are ideas to consider that could get
you up and running, these suggestions are
circumstantial and are solely provided as
assistance to help you make good decisions
while on the road.

5.2 Low LP Gas Pressure

Low LP gas pressure results in a cold gas
flame. The simple test for this problem is to
check the LP gas pressure with a manometer
and make sure there is 11 inches water
column pressure. See our
Video

5.3 Test Each Heat Source

An alternative to testing the gas pressure,
use the shore power (120VAC) heater to run
your refrigerator. If your ARP control
measures "normal" temperatures in the
range given above, but the LP gas does not,
one can deduce that there is an issue with
the LP gas portion of your refrigerator.
To test the electric heater, use the gas flame.
If the boiler temperature is at its normal value
using gas, but lower than normal using
120VAC, there may be a problem with your
120VAC operation
unit goes down, the temperature at which
your boiler will boil the refrigerant goes down
also. Previous to the ARP, the pressure
inside the cooling unit could only be
measured by a cooling unit rebuilder. Now,
the ARP can be used as an indicator by
which to measure the cooling unit pressure.
The first telltale sign of cooling unit failure is
for filter cleaning.
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LP Gas Safety