Table of Contents
Advertisement
Condition
Unit does not heat.
(cont'd.)
Unit overheats/unable to cool.
Rapid drop in pressure/no
pressure.
Noisy pump.
TDH-6 Series Hot Oil Large Temperature Control Units
Possible cause
Controller heater output open.
Clogged Y strainer.
Water supply to unit is turned
.
OFF
Water drain is plugged or
excessive back pressure in drain
line.
Heat exchanger tubes plugged
by lime deposits.
Faulty solenoid valve.
Leaks in connecting lines.
Air in circulating lines.
Low fluid.
Defective Ful-Flo valve.
Water in fluid.
Vent solenoid open.
Pump running in reverse.
Pump repair/adjustment needed.
V belt broken/worn.
Water in fluid.
Severely degraded fluid.
Solution
Check the heater output with an
ohmmeter to ground. It should
read in the mega-ohm range.
Infinite or zero readings indicate
a defective output.
Clean Y strainer.
Open water supply.
Clear drain line or eliminate
back pressure condition.
Remove tube bundles; clean/
replace as required.
Test solenoid valve by switching
to Manual Cool mode and listen
for valve operation. Replace if
faulty.
Inspect/replace faulty line or
connection.
Perform venting sequence in
Chapter 3.
Check fluid level in sight glass.
Add fluid if required.
See Chapter 3.
Drain water from low point in
piping (see Chapter 3), or boil
water off.
Allow vent timer to run out; or,
check valve operation when unit
is cold by opening the fill port.
Check motor; rewire if
necessary. See electrical
diagrams.
Adjust head spacing or replace
worn pump components.
Replace as required.
Drain water from low point in
piping (see Chapter 3), or boil
water off.
Drain and flush system. Replace
fluid.
Page 53
Advertisement
Table of Contents
