© 2007 Duro Dyne Corporation
Printed in USA 10/2007
BI035411
DuroZone
SMZ-AC WIRING INSTRUCTIONS PAGE 5
SMZ-AC SYSTEM CHECKOUT PROCEDURE
The following check-out procedure requires a voltmeter set to read 24 volts A.C..
If, after the check-out procedure is completed, the SMZ-AC panel and dampers are operating correctly, but the system is
not functioning properly, check your wiring carefully. The most common problems experienced are a misplaced wire, a bad
connection or a broken wire. If none of these seem to be the problem, check your thermostats and equipment.
YOU MUST
PERFORM THE FOLLOWING TEST PROCEDURES IN THE ORDER SHOWN. DO NOT SKIP ANY OF THESE
STEPS. PLACE ALL DAMPER SWITCHES IN “O” (OPEN) POSITION.
1. You must have 24 volts across R & C of the SMZ-AC Panel Equipment Terminal Strip. (This powers the SMZ-AC panel
and your equipment).
2. You must have 24 volts across 1 & 2 of the SMZ-AC Panel Equipment Terminal Strip, and every 1 & 2 of each SMZ-
AC Panel Zone terminal. (This powers the dampers).
3. To test the operation of the SMZ-AC panel, you must disconnect all thermostats. With the thermostats disconnected,
and 24 volts as described in #2 above, all dampers should be open. (If the dampers are not open, go to step 4).
3A . To test the heat mode, jump R to W at the SMZ-AC Panel Zone 1 Terminal Strip. Zone 1 will be calling for heat. (All
zone dampers, except Zone 1 will close and the furnace will turn on). The Cool Lockout Relay and Zone 1 Relay will
activate (Red indicator light will glow). Zone 2 or 3 can be activated by jumping W & R at the corresponding SMZ-AC
Zone 2 or Zone 3 Terminal Strips. If the furnace does not activate, test for 24 volts across C & W at the SMZ-AC
Panel Equipment Terminal Strip. If voltage reading is 24 volts, SMZ-AC panel is okay.
3B. To test the cool mode, disconnect the R & W connections made for the heat mode check in step 3A. Jump R &Y at the
SMZ-AC Panel Zone 1 Terminal Strip. Zone 1 will be calling for cooling. (All zone dampers except zone 1 will close,
and the air conditioning will come on.) The Heat Lockout Relay, Equipment 1 Relay and Zone 1 Relay will activate (Red
indicator light will glow). Zones 2 or 3 can be activated by jumping R & Y at the SMZ-AC Zone 2 or Zone 3 Terminal
Strips. If the air conditioning does not activate test for 24 volts across C & Y at the SMZ-AC Panel Equipment Terminal
Strip. If voltage reading is 24 volts, SMZ-AC panel is okay.
3C. To test the Fan, jump R & G at the SMZ-AC Panel Zone 1 Terminal Strip. Be sure at least one Damper Switch is in
“open” “(O)” position. The fan should activate. If the fan does not activate, with R & G jumped, test for 24 volts
across C & G at the SMZ-AC Panel Equipment Terminal Strip. If voltage reading is 24, panel is okay.
4. To test the damper operation, perform step #3A, checking for 24 volts across 1 & 4 of every SMZ-AC Panel Zone
Terminal Strip when that zone is activated, and for “O” volts at 1 & 4 of every SMZ-AC Panel Zone Terminal Strip
that is not activated. (IMPORTANT: This test will work only if at least one zone is activated. If no zone is activated, all
terminal 1 & 4 readings will be 24 volts.) If all readings are correct, the panel is operating correctly. If a damper is not
functioning but the SMZ-AC Panel has checked out okay, check for 24 volts across terminals 1 & 2 on the damper mo-
tor. If you have 24 volts, disconnect the terminal 4 connection to the damper. Jumping terminals 4 & 5 on the damper
motor should make the damper open. (It will take 30 to 60 seconds for a damper to fully open.) When you disconnect
the jumper from terminals 4 & 5, the damper should close. If the damper tested does not operate as described, the
problem could either be binding damper linkage, the blade movement is being obstructed, or you could have either an
incorrect or a defective motor. (With multiblade dampers, it is possible to connect the motor to the linkage 180 “out of
phase”, which causes the damper to be open when it should be closed, and closed when it should be open).
