Honeywell m7415 ユーザーズマニュアル

63-2484—2

14

Single M7415 Damper Actuator accepts thermistor sensor 

input from a C7046A or a C7150B Mixed Air Sensor mounted 

in discharge or mixed air duct. See Fig. 27. 

During the occupied period, on a call for cooling, when outdoor 

air temperature or enthalpy conditions are low, the M7415 

Actuator proportions to maintain between 50°F (10°C) and 

56°F (13°C) at the thermistor sensor. 

If the mixed or discharge temperature is above 56°F (13°C), 

the M7415 Actuator opens to admit additional outdoor air until 

the temperature returns to the 50°F (10°C) to 56°F (13°C) 

range. If the mixed or discharge air temperature is below 50°F 

(10°C), the actuator proportions closed, shutting the outdoor 

air damper until the temperature returns to the 50°F (10°C) to 

56°F (13°C) range. During the occupied period, the actuator 

does not close past the minimum position. 

If the fully open M7415 Actuator cannot satisfy the space 

demand, mechanical cooling is sequenced on. 

During the unoccupied period, the M7415 Actuator overrides 

the minimum position setting and drives fully closed. On a loss 

of power, the actuator spring-returns fully closed. 

If terminals P and P1 are jumpered, the M7415 drives fully 

open; however, if terminals P and P1 are left open, the M7415 

drives fully closed. The M7415 minimum position adjustment 

drives the motor open when the resistance across P and P1 is 

minimal. Increasing the amount of resistance across these 

terminals drives the actuator closed. 

An spst low-voltage controller is used to control the M8405 

Actuator as follows:

a. Fully open—when the controller circuit closes to pro-

vide 24 Vac to terminals D and T, the actuator is 

energized and runs fully open.

b. Fully closed—when the controller circuit opens, 

power is removed from terminals D and T, and the 

actuator spring-returns to the fully closed position.

c. Mid-position—when the controller circuit closes to 

provide 24 Vac to terminals T and X, the actuator is 

energized to run to the adjustable mid-position (mini-

mum position).

Adjustable minimum position can be reached from either the 

fully closed or fully open position. From fully closed, the 

actuator drives open to the minimum position; from fully open, 

the actuator spring-returns to minimum position.

The purpose of an economizer is to use outdoor air for cooling 

whenever possible, to reduce air conditioner compressor 

operation. The W7459 Economizer System, when wired as 

shown in Fig. 27, responds to a signal from the cooling 

thermostat. This system uses a C7400 Enthalpy Sensor or a 

C7650A Temperature Sensor. It responds to both dry bulb 

temperature and humidity, allowing the use of outdoor air at 

higher temperatures for free cooling when the humidity is low. 

The economizer functions as a true first stage of cooling and 

provides maximum fuel economy during the cooling cycle. The 

economizer is automatically locked out during heating. It holds 

the outdoor air damper at the minimum position setting. On a 

call for cooling by the space thermostat, the system operates 

as follows: 

When the enthalpy or temperature of the outdoor air is below 

the setpoint, the outdoor air damper is proportioned open (and 

the return air damper is proportioned closed) to maintain 

between 50°F and 56°F (10°C and 13°C) at the mixed/ 

discharge air sensor. During economizer operation, the 

mechanical cooling is operated by stage 2 cooling on the 

space thermostat. 

When the enthalpy or temperature of the outdoor air is above 

the setpoint, the outdoor air damper closes to its minimum 

position. A call for cooling from the space thermostat turns on 

the mechanical cooling. 

During the unoccupied period, the M7415 Damper Actuator 

spring-returns the outdoor air damper to the fully closed 

position. 

W7212A economizer logic module used with C7400 enthalpy 

sensors, M7215 or MS7505 damper actuators and C7232 CO

2

 

sensors to proportion outdoor and return air dampers from 

economizer and demand control ventilation in commercial 

HVAC equipment.

HEAT PUMP CHANGEOVER (W7213, W7214 ONLY)
In heat pump applications, the controller must have control of 

the changeover valve. To provide the logic module with the 

information necessary for proper information, there must be a 

connection to the logic module O/B terminal. This terminal 

alerts the logic module as to when the system operates in 

cooling (the only time the economizer is used).

W7213 (CHANGEOVER TERMINAL B)
Connect the B terminal according to the following details:

— 24V power to B: System is in heating mode.

— No power to B: System is in cooling mode.

W7214 (CHANGEOVER TERMINAL O)
Connect the O terminal according to the following details:

— 24V power to O: System is in cooling mode.

— No power to O: System is in heating mode.

The minimum position potentiometer keeps the outdoor air 

damper from completely closing during system operation to 

allow ventilation.