User's Manual

Troubleshooting
14 3A2954D
Troubleshooting
Problem Cause Solution
Heater will not heat. No current. Check circuit and fuses.
Overtemperature switch (10) tripped. • Check continuity of
overtemperature switch. If
circuit is open, press red reset
switch and re-check.
Determine why switch opened
before restarting.
• Model 24P016 only: check that
the thermostat (24) is open
when the knob is turned to the
left and closed when turned to
the right.
Burned out heater cartridges (81). Replace cartridges.
Temperature too low. Fluid requires more warm-up time. Increase warm-up time.
Wrong temperature setting. Adjust setting, page 12.
Flow rate too high. Reduce flow rate or use 2 heaters.
Clogged fluid passages. Heater Core Removal and Fluid
Passage Unclogging, page 19.
One of the two heater cartridges (81)
failed.
Check each cartridge for a resistance
of approximately 21 ohms. The pair
in parallel should have a resistance
of approximately 10.7 ohms. See
Heater Cartridges on page 20.
Temperature too high. Wrong temperature setting. Adjust setting, page 12.
Failed primary thermostat (24). Replace, page 16.
High fluctuating temperatures, about
220-250°F (104-120°C) at 0.1 GPM.
Primary thermostat (24) contacts
sticking.
Replace thermostat (24), page 16.
Too much pressure drop or fluid will
not flow.
Flow rate too high. Reduce flow rate or use 2 heaters.
Clogged fluid passages. Flush or clean, page 13.
Heater fittings leak. Loose or damaged fittings. Tighten or replace fittings.
Heater temperature rises far beyond
the setpoint temperature during heat-
ing
Model 262853 only: RTD sensor (88)
is installed too far into fluid path. Sen-
sor does not sense aluminum core.
Replace sensor (88) and compres-
sion fitting (72). See page 21.
Heater core is dirty or has baked on
material.
Disassemble and clean all parts that
come in contact with material.