27
MHGRV-X Field Technical Guide
LED Diagnostics
The Reheat Expansion Module is equipped with four LEDs that
can be used to verify operation and perform troubleshooting.
See
Figure 10, this page
for the LED locations. The LEDs
associated with these inputs and outputs allow you to see what
is active without using a voltmeter. The LEDs and their uses are
as follows:
Operation LEDs
• POWER:
This green LED will light up to indicate
that 24 VAC power has been applied to the Expansion
Module.
• STATUS
:
This green LED will light up and blink every
10 seconds according to valve position. One blink per
10%. Example: valve position is 67%. STATUS LED
will blink six times every 10 second cycle. The STATUS
LED will stay on solid during the two-minute flush
cycle. See
Table 11, this page
.
Communication LED
•
COMM
:
This amber LED will light up and blink once
for every good packet received. Packets should be sent
once every second, so the COMM LED should blink
the same, once every second. The COMM LED should
blink simultaneously on all modules.
Binary Input LED
•
COMPRESSOR ENABLE
:
This green LED will light
up when the Reheat is enabled.
LED Troubleshooting
• “POWER” LED:
When the Reheat Expansion Module
is powered up, the POWER LED should light up and
stay on continuously. If it does not light up, check to be
sure that the power wiring is connected to the board, the
connections are tight, and the transformer is powered.
If after making all these checks, the POWER LED does
not light up, the board is probably defective.
• “STAT” LED:
When the board is first powered up, the
STAT LED will do the following:
○
On for 10 seconds
○
Blinks 30 times
○
Status code repeatedly blinks the indicated valve
position every ten seconds
No. of Blinks
STATUS LED
1-10
Per 10% Valve Position
Solid
During 2 Minute Flush Cycle
Table 11: Reheat Expansion Module ALARM LED
Blink Codes
24VAC
GND
COMM
GND
E
N
A
B
L
E
BLACK
WHITE
RED/GRN
GRN/RED
COND/REHEAT
YS102608 R0
COMM
STATUS
COMM LED
STATUS LED
COMM
STATUS
POWER LED
COMPRESSOR ENABLE LED
Figure 10: Reheat Expansion LED Locations and Descriptions
APPENDIX C: REHEAT EXPANSION MODULE
LED Diagnostics and Troubleshooting
