iWorx® HPU2
Taco Electronic Solutions, Inc.
iWorX-ALM2-APP-102
www.taco-hvac.com
Figure 5: HPU2 Controller LEDs
Status
Network
Service
Troubleshooting Tips
The table below provides solution to some common problems you may encounter.
Problem
Solution
Controller is not running and Status
LED is not illuminated.
No power to controller. Verify the voltage on the controller’s power connector (24 VAC).
How do I reset the controller?
The controller can be reset by the LCI, or you can cycle power to the controller. Refer to
the LCI documentation for more information on resetting the controller using the LCI.
The fan will not cycle on after the
equipment status input alarm has
been resolved
If the controller was previously in a fan fault condition, the controller must be reset
before proper operation can be restored.
The fan and heat/cool pilot relays will
not come on even though the LCI
indicates it is on.
Ensure that the controller and output pilot relay have been powered with 24 VAC and
the output has been correctly wired to the coil of the pilot relay. Also ensure that the pilot
relay has a 24 VAC coil.
The 10K thermistor reading is at its
maximum or minimum.
The input is either shorted or open.
The Heat or Cool outputs will not
come on even though the space
requires conditioned air.
Is there water flow in the system? Verify the associated CCU2 or LHP2 controller are
operating and the HPU2 is a member of the controller. If there is no CCU2 or LHP2 con-
nected, then the Unit Enable input of the ASM2 must detect water flow (On).
Thermistor readings fluctuate rapidly,
sometimes by several degrees.
The controller is not properly grounded. The controller's ground (GND) pin (T40) must
be connected to earth ground. Also ensure that the controller's digital inputs are dry
contacts and that no voltage is being applied or switched to the inputs.
How do I associate my HPU2 control-
lers with the LHP2?
Use the LHP2's grouping mechanism, specifically
Members
on the LHP2 HVAC Setup
screen of the LCI. Only HPU2s may be associated with the LHP2.
