Graco Reactor A-25 Repair Parts page 23

Temperature Sensor
1. Turn main power OFF
supply.
2. Relieve pressure, page 11.
WARNING
Read warnings, page 9. Wait for heaters to cool before
repairing.
3. Wait for heaters to cool.
4. Disconnect temperature sensor wires from J1 on
temperature control board. See T
and F . 4, page 21.
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5. See F . 6. Test with ohmmeter. Between wires (S),
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resistance must be approximately 6 ohms. Between
tip (T) and wires, resistance must be infinity (∞).
6. If sensor fails test, feed wires out of cabinet. Note
path as cable must be replaced in the same way.
7. Loosen ferrule nut (N). Remove temperature sensor
(211) from heater tube (201), then remove sensor
housing (H).
8. Replace sensor, F
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a. Remove protective tape from sensor tip (T).
b. To ensure mixer (202) is out of the way, insert
1/4 in. drill bit into heater tube (201) to a mini-
mum depth of 0.81 in. (20.6 mm). If minimum is
not achieved, mixer must be moved before pro-
ceeding.
c. Apply PTFE tape and thread sealant to male
threads and tighten sensor housing (H) into
tube (201).
309813B
. Disconnect power
3, page 20
ABLE
. 6.
d. Push in sensor (211) so tip (T) contacts heater
element (207), avoiding mixer (202).
e. Tighten ferrule nut (N), holding sensor (T)
against heater element.
9. Route wires into cabinet and thread into bundle as
before. Reconnect wires to board.
10. Turn on heaters A and B simultaneously to test.
Temperatures should rise at same rate (30°F, +/-
4°). If one heater is low, loosen ferrule nut (N) and
tighten sensor housing (H) to ensure sensor tip (T)
contacts element (207).
1
Apply PTFE tape and thread sealant.
2
Apply 110009 thermal heatsink compound.
207
N H
1
211
201
202
S 208
F . 6. Temperature Sensor
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T
2
TI3249a
Repair
23