EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX 732-446-5362 E-Mail- [email protected]
24
ISOLATING 24vac SHORTS
Dampers not responding and THE
UZC4 LED’s are Off or On.
HVAC system not responding and
UZC4 LED’s are Off.
DETECTING 24vac SHORTS
Check HVAC/UZC4 system transformer supply voltage.
Check HVAC/UZC4 system 24vac transformer voltage/fuse/UZC4 circuit
breaker. Check the Fire Alarm system. The UZC4 will not operate if the fire
alarm is active and the interlock is used.
24vac can be read across an open FA circuit.
Check HVAC system wiring for shorts/miswiring.
Check HVAC system wiring for proper connections.
Check HVAC thermostat for proper connections.
Refer to Technical Bulletin for correct Setup/Wiring/Dip Switch settings.
Check HVAC system wiring for proper connections.
Check HVAC system wiring for shorts/miswiring.
Check HVAC System.
Check HVAC System technical documentation and Mfr’s Technical Support.
SOLUTIONS
T R O U B L E S H O O T I N G
REFER TO THE DAMPER MOTOR TESTING PAGE 8
LED’s illuminate and HVAC system
functions normally but dampers do
not respond.
Check damper motor wiring for proper connections.
Check damper motor 24vac transformer voltage/fuse/UZC4 circuit breaker.
Check damper motor wiring for shorts/miswiring.
Refer to Technical Bulletin for correct Setup/Wiring.
F1 circuit breaker protects the UZC4
and all connected modules. Reacts to
a short in the damper motor or
thermostat component and field wiring.
CHECK YOUR WIRING
EWC Controls provides superior toll free Troubleshooting Support for the UZC4 when you are on the job site!
Call 1-800-446-3110 Monday - Friday 8am to 5pm East Coast Time.
Otherwise call 1-732-446-3110 for information on the UZC4 and other ULTRA-ZONE products.
When calling for Technical Support, please have a multi-meter, pocket screwdriver, and wire cutter/stripper handy.
TECHNICAL SUPPORT
LED’s do not illuminate and HVAC
system does not respond.
LED’s are not responding properly
and HVAC system is malfunctioning.
LED’S are responding properly but
HVAC system is malfunctioning.
SYMPTOM
Disconnect the wire(s) from the ‘R’
terminals on the UZC4 thermostat terminal
blocks ,
and the
“M2/M4/M6’’ terminals
on the UZC4 damper motor terminal
blocks. Restore power. If the short is no longer present, Ohm out the
thermostat and damper field wiring for shorts/misconnections. Replace or repair
wires as necessary. Restore power. Module(s) will resume operation.
SOLUTIONS:
Remove 24vac power from UZC4 and reset the manual circuit breaker or allow
the thermal breaker to cool off. Find and repair short(s) in damper and/or thermostat field wiring.
Restore 24 vac power.
If 24vac short has occurred, 24vac will be present at the
UZC4 Module Input terminals R & C;
but
24vac will not be present at the
Thermostat R&C
terminals. The Ground Fault LED is illuminated!
SYMPTOMS: Modules, Motors or both will not function
T E S T I N G C O N V E N T I O N A L T H E R M O S TAT S
During a demand for heating, the thermostat should apply a 24vac hot signal to the W1 and or W2 terminals.
During a demand for cooling, the thermostat should apply a 24vac hot signal to the Y1, Y2 and G terminals.
During a continuous fan demand, the thermostat should apply a 24vac hot signal to the G terminal.
Check to make sure that the thermostat Rc and Rh terminals are connected together, unless your application requires
separation of these circuits.
Use the (C) Common terminal provided at each thermostat terminal block to wire up full 24 vac hard-wired thermostats.
You should reference the (C) Common terminal when troubleshooting incoming thermostat demand signals, even if no wire is
connected there.
