TestEquity FastRate 3007C - Page 40

Chapter 7 – Maintenance
Page 7-10 TestEquity 3007C Temperature Chamber
SYMPTOM
CONDITION
CAUSES
R-508B standby pressure is
less than 132 PSIG.
1. When unit is off and system is
equalized.
1. Low charge (leak).
R-404A sightglass has
bubbles or does not look full.
1. During all running conditions.
2. Only when cool light is cycling.
1. Low charge (leak).
2. No problem. This is normal.
Cools too slow or does not
reach –73°C.
1. R-508B standby is ok, no
bubbles in R-404A sightglass.
1. Chamber interior is overloaded.
Test sample is energized, giving
off heat. Circulator motor is not
turning. Port plug is not in port.
Door is not sealing completely.
Ice on evaporator.
Cools all the time.
1. When cool light is OFF.
1. Solenoid valve SV1 may be
defective in open position.
Temperature varies more
than ±0.5°C or 1°C total.
1. If tuning PID control parameters
in temperature controller were
changed.
2. If tuning PID control parameters
in temperature controller are as
shipped from TestEquity.
3. If tuning PID control parameters
in temperature controller are as
shipped from TestEquity and
only occurs in cool mode.
1. Re-enter values as shipped from
TestEquity.
2. Control parameters may need to
be changed for your unique test
conditions.
3. Control parameters may need to
be changed for your unique test
conditions. R-508B hot gas
bypass regulator may be
defective or set too high.
Compressors turn on and off
too frequently.
1. If compressor control
parameters in temperature
controller were changed.
2. If compressor control
parameters in temperature
controller are as shipped from
TestEquity.
1. Re-enter values as shipped from
TestEquity.
2. Control parameters may need to
be changed for your unique test
conditions. Solenoid valve SV1
may be defective in open
position.
Excessive noise and
vibration when the
compressor starts.
1. Chamber has been off for
several hours or more and is not
connected to source of power,
or main disconnect switch is off
during that time.
2. Chamber has been off for
several hours or more, and is
connected to source of power
and main disconnect switch is
on during that time.
1. The chamber must be connected
to the power source AND the
main disconnect switch must be
on for 3 hours prior to operating
the chamber.
2. Crankcase heater defective
(open).