IQ Load Controller Additional Info

Load and Solar Circuit Control using IQ System Controller Auxiliary Contacts
30 © 2021 Enphase Energy Inc. All rights reserved. December 16, 2021
Validation and Troubleshooting Guidelines for setting up a custom
Load Control kit
Install Validation
1. Ensure control transformer is wired correctly.
a. Confirm that there is 120 Vac to primary with appropriate fusing.
b. Confirm that there are no shorts on the secondary
c. Confirm that there are 24 Vac on the secondary.
d. Important: never wire 120 Vac to the auxiliary contactors on IQ System Controller. The
auxiliary contactor inputs on IQ System Controller must be 24 Vac or 12V DC.
2. Prevent overloading of control transformer:
a) Secondary current must be less than 1 A and must be capable of delivering contactor inrush.
b) Overloading the control transformer will cause the control transformer to fail or the fuse on
the primary side to blow. Always match the control transformer output to the inrush and
steady state power drawn by the external contactor.
c) If you are not certain about the inrush and steady state power requirements of the external
contactor, we recommend using one control transformer per external contactor.
d) If two or more external contactor control circuits are powered using a single control
transformer, use a fuse on the secondary side of the control transformer as well the primary.
3. Ensure contactor coils are wired correctly:
a. Check the contactor specification and ensure that the wire the output of the control
transformer output is wired to the appropriate contactor coil terminal.
b. The external contactor must close when energized. An on-grid contactor should have 24ac
across its coils.
c. The Voltage across output terminals of the contactor must be the same as the input
terminals.
Troubleshooting
Step
Symptom
Possible cause
Solution
1
Transformer is not
powered. Diagnosed
by measuring AC
voltage on the
secondary.
Tripped breaker or blown fuse.
This can occur due to short on
secondary such as the control
wires landed on a single
terminal of the contactor coil.
This can also result in
transformer is damage. When
overloaded it is possible that
transformer primary is
damaged.
Ensure correct over current
protection is installed on the
primary and optionally secondary
and replace transformer. Confirm
there are no shorts and there is a
circuit through all components.
2
Contactor is not
powered. Diagnosed
by measuring AC
voltage on contactor
coil and NO1/NO2
Auxiliary contact
NO1/ NO2 Auxiliary contact is
not configured. As result there
will be voltage drop across
NO1/NO2
Ensure Auxiliary contacts are
configured and provisioned in
Enphase Installer App
3
Contactor is not
powered. Diagnosed
by measuring AC
voltage on contactor
coil.
Contactor isn’t energized.
Faulty wiring between auxiliary
contact in IQ System
Controller and definite purpose
contactor.
Confirm 24V AC across aux
contacts when terminal block is
unplugged.
Refer Figure 1 Auxiliary contact
labelling and usage for identifying
the auxiliary contact terminals in
IQ System Controller.