Supply Air Delivery; Blower Delays; Gas / Electric Units; Electric / Electric Units - Lennox Prodigy 2.0 Application Manual

9. Supply Air Delivery

9.1.

Blower Delays

The following is summary of blower delay options, For more details refer to sections 3.3.9 and 3.3.10.
9.1.1.

Gas / Electric Units

The blower default delay is 40 seconds (Parameter 66 ­ HT GAS BLR ON DELAY) after the gas valve is energized and a
default of 120 seconds (Parameter 67 ­ HT GAS BLR OFF DLAY) after the gas valve is de­energized. The blower operates
anytime a heat limit trips.
9.1.2.

Electric / Electric Units

The blower on delay is set to 0 seconds. The blower is delayed off by default for 20 seconds (Parameter 60 ­ HT ELEC BL
OFF DLAY) after the electrical heating is terminated.
9.1.3.

Cooling Operation

The default on and off delays are 0, but may be adjusted by Parameter 79 (COOL BLR ON DELAY) or Parameter 80 (COOL
BLR OFF DELAY). The on­delay time period starts when the cooling demand is initiated. The off­delay time period starts
when the cooling demand is terminated.
9.2.

Supply Constant Air Volume (CAV) Control Mode

Units with Constant Air Volume have single-speed motor with belt driven blower. The same air volume is delivered for all
operating modes (heating, cooling and ventilation) and stages. These units are indicated by blower type B in the model
number (character 8 ­ refer to Appendix B for more details). All blower on and off delays described above still apply.
9.3.

Supply Multi-Stage Air Volume (MSAV) Control Mode

Units with Multi-Stage Air Volume are capable of delivering two or more stages/volumes of supply air. There are three blower
types supported for Multi-Stage Air Volume:
•
Belt driven blower with motors and external variable frequency drives – Blower type M in model number.
•
Direct driven blower using motors with integrated variable frequency control – Blower type E in model number.
•
Belt driven blower with two-speed motors ­ Blower type T in model number.
Refer to Appendix B for more details on Model Number structure.
9.3.1. A Box (3­ to 5­ton Units)
Energence A Box 3­ to 5­ton units use direct driven blower (high efficiency units) or two speed belt driven blower (standard
efficiency) with a single, 2­step capacity, compressor.
NOTE: The 6­ton Energence A Box has a single capacity compressor, and a single speed blower, so it is not an MSAV type
of unit, and the following does not apply to it.)
•
High Efficiency Energence A Box Units use a Direct­Drive ECM Constant Torque Motor. The blower runs at a
selected high or low output depending on unit operation. The actual blower speed and CFM delivered will depend on
the flow restriction as well as the percent output. The blower output for each mode of operation has been factory set,
but it will need to be adjusted based on the installed duct­work and the air delivery required for the application. The table
below shows the default blower outputs parameters. The table also shows, for units equipped with an economizer or
motorized outdoor air damper, the damper percent output when the blower is running and the space is occupied. The
default value of 101 for Parameter 29 indicates that parameter 9 or 132 is used during the blower only operation. Setting
Parameter 29 to a value in the range of 0­100 will activate this functionality.
Table 34. High Efficiency Factory Settings (as percent output) ­ A Box (3­ to 5­ton Units)
Cooling low, Free cooling low, Ventilation low
Cooling high, Free cooling high, Ventilation high, Heating
Smoke alarm modes
Minimum damper during low blower
Minimum damper during high blower
Minimum damper for blower only
Operation 3­ ton 4­ ton
28% 33%
55% 58%
55% 80%
101%
Page 44
5­ ton
36%
59%
59%
0%
0%
Parameter
8
7
6
9
132
29