Graco B Series Instructions-Parts List Manual page 17

Problem
Heater Control indicator lamp stays
on (continued)
Heater Control indicator lamp
stays off – no heat.
Temperature erratic or
inaccurate
Large pressure difference between
ISO and RES side, For example:
600 psi (42 bar) ISO 600 i (42 b ) ISO
1000 psi (70 bar) RES
Troubleshooting
Cause
The ATC, if used, is not plugged in
Circuit board out of calibration
Sensor Probe (256) not plugged in
Thermostat(s) (252) open
(normally closed)
Triac wires not connected properly
Temp Set dial wires not connected
Faulty circuit board
AC power wiring or voltage problem
Elements burned out or not plugged
in
Sensor probe (256) out of
position
Heater out of calibration
Improper incoming voltage
One thermostat open
(normally closed)
(Model 235–260 & 235–840 only)
Faulty sensor probe (256)
Thermostat(s) (252) open
Fluid on high pressure side is too
thick
Gun nozzle impingers clogged or
damaged
Blocked filters
Clogged hoses
Fluid supply low or empty
Fluid pump or hose connections
leaking
Solution
Be sure ATC connector, if used, is properly
plugged into circuit board.
Check resistance. See page 18.
See page 28. Calibration procedure is included
in replacement procedure.
Plug in. See page 23.
Reset thermostat by pushing reset button. See
Fig. 13, page 22.
Check triac detail. See Fig. 14, page 22.
Check wiring. See Fig. 10, page 19.
Replace. See page 26.
Check for 200–240 VRMs. See Adjust the
Heater, Step 1, page 15.
Check element resistance. See page 18.
Probe must protrude 1.44" (36 mm) from
manifold. See Fig. 16, page 23.
Indicator light should go out within 5 seconds of
shutting gun off after flowing.
Calibrate controls. See page 28.
Check the wiring and the voltage:
200–240 VRMs during fluid flow and at stall.
See Adjust the Heater, Step 1, page 15.
Reset thermostat by pushing reset button. See
Fig. 13, page 22.
Check resistance. See page 18.
Replace. See page 23.
Reset thermostat by pushing reset button. See
Fig. 13, page 22.
Increase heater temperature on high pressure
side to reduce viscosity, which should level the
pressure, OR lower the temperature on the low
pressure side.
Clean nozzle. Using an oversized cleanout pin
or damaging nozzle during cleaning may
increase impinger hole size and cause an
imbalance of fluid. See gun manual 307–546.
Check outlet filter (112; also see manual
307–273).
Check gun check valve screen. See gun
manual 307–546.
Flush clean, if possible, or replace hose. Use
and clean filters regularly. Don't allow mixed
fluid to back up into hoses.
Refill; prime system to remove air.
Check for leaks and repair or tighten as
needed. See pump manual also.