Lennox VPB036H4M, Installation Instructions Manual

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Figure 19. Fan Speed Control Connections
Fan Speed Control & Setup
CN66
CN56 CN55
CN60CN59
CN61
CN51
L
COM
Vo+ 0 0 Vi+
Ho Mo Lo FAN
0-10V
Input
0-10V
Output
CN62
Li Mi Hi COM
Dry contact input
Dry contact output
The AHU Control Kit has 3 digital inputs, 1 analog input,
3 digital outputs and 1 analog output for fan speed con-
trol.
Either analog input or 1 of 3 digital input signals is re-
ceived. Both analog output and 1 of 3 digital outputs are
transmitted.
Fan Signal Description Input /
Output
Analog /
Digital
Signal Type Signal Spec Connector
Hi High Speed Input Signal input digital dry contact 0~24V 0~1A CN59
Mi Medium Speed Input Signal input digital dry contact 0~24V 0~1A CN59
Li Low Speed Input Signal input digital dry contact 0~24V 0~1A CN60
Vi+ Variable Speed Input Signal input analog VDC 0~10V CN62
Ho High Speed Output Signal output digital dry contact 0~24V 0~1A CN56
Mo Medium Speed Output Signal output digital dry contact 0~24V 0~1A CN55
Lo Low Speed Output Signal output digital dry contact 0~24V 0~1A CN55
Vo+ Variable Speed Output Signal output analog VDC 0~10V CN61
Table 6. Fan Speed Control Input and Output Channels
In cooling operation, fan speed is determined by the ther-
mostat fan setting. When set at AUTO, the speed may
vary and is determined by AHU control kit. When set at
high, medium or low, the speed is fixed. The speed signal
is transmitted at Ao AND one of Ho, Mo or Lo.
In heat pump heating operation, fan speed is the same
as in cooling operation.
In fan only operation, fan speed is the same as in cooling
operation.
In auxiliary heating operation, fan speed is the same as
in cooling operation. See Figure 1.
In alternative heating operation, fan speed is determined
by the 3rd party heat source controller (e.g. gas furnace
controller, oil burner controller, etc.). The speed signal is
received from the 3rd party heat source controller to AHU
Control Kit at terminal either Ai OR one of Hi, Mi, or Li.
Then the speed signal is transmitted from AHU Control
Kit at terminals both Ao AND one of Ho, Mo, or Lo. See
Figure 2.
The correlation between analog and digital signals is set
by ENC2, 3 and 4 per Table 7.
NOTE - When 2, 3 or 4 kits are connected in parallel to
control a large AHU, fan speeds (both inputs and out-
puts) are set at the main kit (see DIP SW2).