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62-0101

To check out the ML6161 when controlled by the T641,

determine the direction the damper shaft moves to open the
damper (cw or ccw). See Fig. 7. Place 24 Vac across the
appropriate common-c

w     

or common- ccw

terminals to energize the actuator. The ML6161 should
begin  to open the damper. If the motor does not run, try
switching the 24 Vac across opposite common-cw or ccw
terminals to determine if the damper will begin to close.
Replace the ML6161 if the motor does not run in either
direction.

With the T641 controlling the ML6161 or equivalent

actuator, lower the set point of the thermostat to call for
cooling. Observe the operation of the motor. If the damper is
closed, it should begin to open. If not, adjust the set point of
the T641 higher to determine if the wiring is correct. If no
movement is observed, check for the presence of 24 Vac
between terminals C and Y during a call for cooling. With the
proper wiring and 24 Vac present, the actuator should operate
correctly. If 24 Vac is not present between C and Y on a call
for cooling, replace the T641.

Checkout

Summary of Contents for T641A

Page 1: ... is sized to handle an average peak load notthesumoftheindividualpeaks Aseachzonepeaks at a different time of day extra air is borrowed from the off peak zones This transfer from low load to high load zones occurs only in true VAV systems Pressure dependent systems do not incorporate an indi vidual zone air flow sensor and depend on a stable system pressure to maintain flow These systems require s...

Page 2: ... and ordinances The T641 utilizes a four wire opera tion so an additional transformer common wire must be present for correct wiring and operation See Fig 2 for functional schematic of T641 Screw terminals are on the back of the thermostat See Fig 3 Thepartno 221618CoverPlateisavailablewhenreplac ing a competitive device that has left marks on the wall See Fig 4 1 Grasp the thermostat cover at the...

Page 3: ...NG SCREWS 4 THERMOSTAT COVER M6111 EXTERNAL SET POINT LEVER Fig 4 Mounting T641 using the accessory wallplate Y C X W R 80 70 60 50 OFF ON SYSTEM OVERRIDE SPIRIT LEVEL WALLPLATE HEATING CONTACT MOUNTING HOLES 4 COOLING CONTACT INTERNAL SET POINT LEVER MOUNTING HOLES 4 WIRING TERMINAL UP TO 5 M 965 FRONT OF THERMOSTAT COVER REMOVED BACK OF THERMOSTAT ...

Page 4: ...les and tighten 7 Replace the thermostat cover WARNING Because the cooling anticipator operates continu ously in the floating band the T641 incorporates a factory offset that calibrates the thermostat The offset causes the T641 to appear to be switching 10 5 F lower when not powered compared to actual operation The cooling anticipator is needed to provide proper thermostat cycling by matching the ...

Page 5: ...o close Replace the ML6161 if the motor does not run in either direction With the T641 controlling the ML6161 or equivalent actuator lower the set point of the thermostat to call for cooling Observe the operation of the motor If the damper is closed it should begin to open If not adjust the set point of the T641 higher to determine if the wiring is correct If no movement is observed check for the ...

Page 6: ...6 Automation and Control Solutions Honeywell International Inc Honeywell Limited Honeywell Limitée 1985 Douglas Drive North 35 Dynamic Drive Golden Valley MN 55422 Scarborough Ontario M1V 4Z9 6 ...

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