PH-20/PHX-20 Manual
46
MAINTENANCE
Material Heater (cont’d)
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 Proportioner 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.
Heating Rod
To replace 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 (see
page 39). Do not loosen or tighten Thermocouple Body.
2. Disconnect the suspect Heating Rod from the wire connections and test Heating
Rod again for proper electrical resistance. 1250 Watt Heating Rod is 37 ohms,
1500 Watt Heating Rod is 31 ohms.
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.
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.
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