Product Overview

VC6936
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
® U.S. Registered Trademark
© 2011 Honeywell International Inc.
95C-10909—03 T.D. Rev. 02-11
Printed in U.S.A.
OPERATIONS
WITH SERIES 60 FLOATING (TRISTATE) CONTROLLER
(refer to Fig. 5)
The series 60 floating controller is an SPDT contact closure
outputs with a centre-off position. On a change in temperature
from the set point, the controller will close either the Open or
Close contacts, creating a momentary voltage pulse on the
gray or white input leads, driving the valve to a new position.
The pulse must be at least 1/2 second long in order to be
detected by the VC6936. The pulse can be held as long as
necessary.
For control stability, the stroke time of the actuator while
powered has been simulated at 120 seconds. In fail safe and
testing operation, the actuator travels through its stroke in 12
seconds.
POWER FAILURE REPOSITION (FAIL SAFE OPERATION)
On a loss of power, the actuator will drive to its stand-by
position using energy stored in the super capacitors, and will
resume normal operation on power up. On loss of signal, a
VC6936 wired for PFR-Open will open the A port fully. A
VC6936 wired for PFR-Close will close the A port. The motor
can drive the valve through its full stroke in 12 seconds.
PFR position is chosen during installation. The black wire is
connected to common (blue) to fail safe open, or to 24 V
(brown) to fail safe closed.
The PFR position can be controlled dynamically with a SPST
signal by applying 24V power to the PFR direction selection
lead while power is present. Applying 24V will cause the valve
to close the A port when power is lost. Not applying power will
cause the valve to open the A port when power is lost. This
can be useful in 2-pipe systems where both hot and chilled
water maybe used depending on the season, and a different
fail safe mode is required for each condition.
Because of the soft close off characteristic of the VC valve,
initial (and final) movements of the actuator do not cause
significant changes in the valve stem position.
START UP
On initial power-up, the capacitors will take about 60 seconds
to charge. The LED will flash slowly during this period. When
ready, the actuator will drive the valve through one full stroke
cycle over 24 seconds to calibrate its position, and exercise
the valve cartridge, the LED will glow steadily.
This self-calibration action repeats daily. If anything interferes
with the self-calibration process, the LED will flash rapidly and
the actuator will not respond to control signals.
CHECKOUT
1. Raise the set point of the thermostat above room tem-
perature to initiate a call for heat, if the valve is wired for
heating control.
2. Observe all control devices - 2 way valve should open
or port A in 3 way valve should open, and port B should
close in 120 seconds.
3. Lower the set point of the zone thermostat below room
temperature.
4. Observe the control devices. 2 way valve should close
or port A in 3 way valve should close, and port B should
open in 120 seconds.
5. Remove power from the actuator. The VC6936 waits 3
seconds then drives valve to its fail safe position, e.g.:
open, in 12 seconds or less.
6. Restore power to the actuator. Valve should drive to the
position required by the thermostat or controller in 120
seconds or less.
SERVICE
This valve should be serviced by a trained, experienced
service technician.
1. If the valve is leaking, drain system OR isolate valve
from the system. Do not remove body from plumbing.
2. Check to see if the cartridge needs to be replaced.
3. If the motor or other internal parts of the actuator is
damaged, replace the entire actuator assembly.
NOTE: Honeywell hydronic valves are designed and tested
for silent operation in properly designed and installed
systems. However, water noises may occur as a
result of excessive water velocity. Piping noises may
occur in high temperature (over 212 °F [100 °C]) sys-
tems with insufficient water pressure.
TO REPLACE ACTUATOR
Replacement of an actuator does not require draining the
system, provided the valve body and valve cartridge assembly
remain in the pipeline.
1. Check replacement part number and voltage ratings for
match with old device.
2. Disconnect power supply before servicing to avoid elec-
trical shock or equipment damage.
3. Disconnect leadwires to actuator and remove. Where
appropriate, label wires for rewiring.
4. The actuator head is automatically latched to the valve.
To remove, press up on the latch mechanism with your
thumb. It is located directly below the white manual
open lever (see figure 3). Simultaneously press the
actuator down towards the body with moderate hand
force and turn the actuator counter-clockwise by 1/8
turn (45 degrees). Lift the actuator off the valve body.
5. Install the new actuator by reversing the process in (4).
6. Reconnect leadwires.
7. Restore power, and check out operation.