Installation and Maintenance Manual

Troubleshooting
56 VAV-SVX01D-EN
• Measure the power input to 24 VAC terminal and
Common/ground terminal of the ECM board.The
supply voltage should be between 19.2 and 28.2
VAC (24 VAC cataloged). However, voltages at
either extreme may result in system instability.
• If low or no voltage, check up stream of controller to
see how voltage has been interrupted. See
complete wiring diagrams (Figure 50, p. 64 and
Figure 51, p. 65).
2. Testing Binary Output
• Measure voltage from White to Green wire on
connector
• Should be between 9 to 30VDC. If not replace ECM
3. Testing Analog variable speed output
• On ECM-DCU change board selector switches to 0
on each one of the switches to give a 100% output
signal. On ECM-VCU adjust potentiometer until
LED's read a 100% output.
• Measure voltage from green to red wires on 4 pin
connector and document. See Figure 50, p. 64 and
Figure 51, p. 65 for correct unit wiring diagram.
• Should measure above 9VDC
• Change ECM-DCU board selector switches to 9 on
tens digit an 9 on units digit to give a 99% output
signal. On ECM-VCU adjust potentiometer until
LED's read a 99% output
• Measure voltage from green to red wires on 4 pin
connector and document. See Figure 50, p. 64 and
Figure 51, p. 65 for correct unit wiring diagram.
• Should measure less than previous reading
• Continue process until all selector switch positions
have been checked to find any dead spots in
selector switches
• If unit ECM board fails any of these tests replace
board. If ECM is found to be good but motor still
does note operate contact VAV technical support.
VAV Electric Heat Stage(s) Failure
Procedures
In the event that the heat outputs are not energizing,
properly inspect the following:
1. Zone temperature is at or above the heating set point
• Increase the UCM heating set point.
2. Verify the output configuration in the UCM setup
menu.
• Unit needs to be configured as 3 stage Electric heat
3. Tracer Summit has the electric heat output disabled
• Check group, global, and/orTracer overrides to
make sure they are not inhibiting heat operation.
4. Minimum heating CFM is not being met, airflow is too
low
• Increase the airflow or lower the minimum heating
flow.
5. Heat relays have failed
• If VAV UCM is calling in the status menu for the
electric heat to be on and it is not then check UCM
Triac output; wiring; and Relay output.
• Check J8 toTB1-2. Should have 24VAC; if it does not
measure the power input toTB1-1 (power) andTB1-
2 (ground) of the UCM board.The supply voltage
should be between 20 and 28 VAC (24 VAC
cataloged). However, voltages at either extreme
may result in system instability.
• HeatTriac(s) can be checked with purchasing a 24
VAC LED and see if it lights up on call for Heat stage
UCM. If LED does not light up replace UCM.
• Move electric heat relay wires from UCM and apply
24 VAC directly.
• Electric heat stage should energize. If it does not;
check wiring, safeties and electric heat contactor.
Replace components as necessary.
VAV Proportional Hot water failure
Check binary outputs
In the event that the heat outputs are not energizing,
properly inspect the following:
1. Zone temperature is at or above the heating set point
• Increase the UCM heating set point.
2. Verify the output configuration in the UCM setup menu
• Unit needs to be configured as proportional hot
water
3. Tracer Summit has the heat output disabled
• Check group, global, and/orTracer overrides to
make sure they are not inhibiting heat operation.
4. Heat relays have failed
• If VAV UCM is calling in the status menu for the
valve to be open and it is not then check UCMTriac
output; wiring; and Relay output.
Figure 43. ECM
NOTICE:
Equipment Damage!
UCM Outputs are switched to ground. Do not jumper
24 VAC to J9, J10, or J11 because damage will occur.