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SYMPTOM
Motor
overheats/smoke/component
burn-out
ML will not respond
Vdc/mA signal drops when
connected to ML
Actuator yoke corrodes
Floating Actuator position
"drifts" when used with
building automation system
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
www.honeywell.com/building/components
06/06 RJ
© Honeywell 2006 Printed in Canada
95C-10939-4
POSSIBLE CAUSES
Current sensing circuit failed or electronic
components failed
Incorrect DIP switch settings
No control signal present
Incorrect wiring connections
Internal time delay
No or low power supply
Error mode (gearbox damage)
ML7984 in mA mode with voltage input
Signal degradation due to incompatible load
impedance
Galvanic reaction from dissimilar metals if
SS U-bolt used with aluminum yoke
Mismatch between actuator resolution (30
steps) and BAS controller
Honeywell Limited-Honeywell Limitee
35 Dynamic Drive
Toronto, Ontario, M1V 4Z9
ACTIONS
Replace actuator. Make sure:
1) Correct actuator used
2) Properly installed
3) Do not operate actuator before
mounting on valve supply
4) Proper voltage supply
5) Use high temperature kit
(43196000-001)
LED (on):
Check against Product Instruction
Sheet
Check controller
Check against Product Instruction
Sheet
Allow at least 1/2 - 1 second for the
ML to respond
LED (off):
Check voltage on T5 & T6
terminals
1) Check power supply
2) Check callibration cycle
3) Valve stroke length less than 1/2"
or greater than 1 1/4"
4) Reset device by a momentary
disconnect of power at T5 and T6.
Change DIP switch setting
Output and ML Input Impedance
specifications
Replace U-bolt with galvanized U-
bolt and nuts
1) Read actual valve position using
272630D feedback module
2) Rewire actuator for 3-wire
control
3) Program daily valve reset
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