BAS-SVX084A-EN
69
Troubleshooting
VAV Modulating Hot Water Failure
In the event that the heat outputs do not energize, check the following:
•
Zone temperature is at or above the heating setpoint. Increase the Symbio 210 controller
heating setpoint.
•
Verify the valve control type selection on the TU Equipment Configuration screen. Unit needs
to be configured as modulating hot water.
•
Tracer SC has the heat output disabled. Check overrides to ensure they are not inhibiting heat
operation.
•
Heat relays have failed.
–
If the Symbio 210 controller is calling for binary output (viewed in the Status screen), then
the LED is ON for the correct binary output to open the valve. If the TRIAC is not closed, then
check the Symbio 210 controller TRIAC output, wiring connections, and relay output.
–
Check for correct binary outputs. It should have 24 Vac. If it does not, measure the power
input to XFMR 24 Vac input and
of the Symbio 210 controller. The supply voltage should
be between 20.4 to 27.6 Vac (24 Vac cataloged). However, voltages at either extreme may
result in system instability.
–
Heat TRIAC(s) can be checked by purchasing a 24 Vac LED and connecting to the TRIAC
output. If they are lit, it is calling heat output to be OPEN or CLOSED by the Symbio 210
controller. If LED is not lit, replace the Symbio 210 controller.
WARNING
Live Electrical Components!
During installation, testing, servicing and troubleshooting of this product, it may be necessary
to work with live electrical components. Have a qualified licensed electrician or other
individual who has been properly trained in handling live electrical components perform these
tasks. Failure to follow all electrical safety precautions when exposed to live electrical
components could result in death or serious injury.
NOTICE
Equipment Damage!
The Symbio 210 controller outputs are switched to ground. Do not jumper 24 Vac to binary
output TRIAC(s) because damage will occur.
