POLYURETHANE
MACHINERY
CORPORATION
PHDX-2 SERVICE MANUAL
13. MAINTENANCE
WARNING!
Before performing any maintenance, make sure the
Main Power Switch is OFF and incoming power is locked OFF.
NEVER access the inside of the Control Panel with the Propor-
tioner power supply ON. The Heaters are components that reach
high temperatures; you must wait until they have cooled before
handling and bleed all material pressure to zero.
To replace a defect Heating Rod, proceed as follows:
1. Ensure Main Power Switch is OFF and incoming power is locked OFF. Depressurize
proportioner and remove the Cover on Heater.
WARNING!
If the Heating Rod to be replaced is the one in
contact with the Thermocouple, it is necessary to remove the
Thermocouple first. Do not loosen or tighten Thermocouple
Body.
2. Disconnect the suspect Heating Rod from the wire connections and test the Heating
Rod again for proper electrical resistance.
Heating Rod
Ohm Measurement per
Rod
Total Ohm
Measurement per Fluid
Side
1250 WATT
39.0 Ω
13.0 Ω
1500 WATT
32.4 Ω
10.8 Ω
1750 WATT
27.5 Ω
9.2 Ω
3. Unscrew the Heating Rod and remove from the Heater Block along with its Spring and
inspect; it must be smooth and shiny in appearance. If it is blackened or has material
adhered to it replace the Heating Rod, even if ohm reading is acceptable.
4. Apply Teflon Tape or appropriate Thread Sealant to the Heating Rod thread and
assemble Heating Rod and Spring into the Heater Block. Tighten securely to 110
ft/lbs (150 Nm)
5. If necessary carefully re-install Thermocouple ensuring positive physical contact with
the Heating Rod. Make sure the Spring does not prevent the Thermocouple from
making contact with the Heating Rod. Tighten Nut with open-end wrench.
6. Reconnect wire connections and replace Cover.
7. Ensure Heater is full of material prior to electrical testing.
REVISION 1.1
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