Carrier 62E User Manual

Page 25

button again to return to the main screen. Replace the user con-

trol cover.

Modulating CO

with Balanced Air Option (Fig. 20) —

This option allows the user to enter minimum and maximum

outside airflow levels. The user will then be allowed to enter

minimum and maximum CO

levels. The EzERV program will

modulate the cfm of the ERV based on the building CO

level.

To enter the user settings press the pushbutton once to display

the minimum cfm screen. Adjust the knob clockwise to

increase and counterclockwise to decrease the minimum cfm

level.

Press the push button again to display the maximum cfm

screen. Adjust the knob clockwise to increase and counter-

clockwise to decrease the maximum cfm level. See Fig. 21.

Press the push button again to display the minimum CO

level screen. Adjust the knob clockwise to increase and coun-

terclockwise to decrease the minimum CO

level. See Fig. 22.

Press the push button again to display the maximum CO

level screen. Adjust the knob clockwise to increase and coun-

terclockwise to decrease the maximum CO

level. See Fig. 23.

The exhaust airflow will automatically adjust to equal the

supply airflow. Press the button again to return to the main

screen. Replace the user control cover.
NOTE: The scale for the cfm vs. CO

level is based on a CO

sensor that outputs 0-vdc at 0 ppm CO

and 10-vdc at

2000 ppm CO

. For example, using the figures above, the air-

flow would modulate linearly from 1458 L/s (3090 cfm) at

3vdc to 2336 L/s (4950 cfm) at 5-vdc. A signal below 3-vdc

would result in a constant 1458 L/s (3090 cfm) while a signal

above 5-vdc would result in a constant 2336 L/s (4950 cfm).
Modulating CO

with Offset Air Option — Follow the steps

above for modulating CO

with balanced air. After setting the

maximum CO

level press the push button again to display the

exhaust air offset screen. A negative exhaust air offset would

equate to a smaller amount of air being exhausted from the

building when compared to the outside air being supplied to the

building. Adjust the knob clockwise to increase and counter-

clockwise to decrease the exhaust offset cfm level. Press the

button again to return to the main screen. Replace the user con-

trol cover.
Building Pressure Control Option — This option will hold

the outside air cfm level constant and will modulate the exhaust

airflow to maintain the building pressure set point. Press the

push button once to bring up the ERV cfm screen. Turn the

knob clockwise to increase or counterclockwise to decrease the

amount of outside air coming into the building. Press the push

button again to display the "Building Pressure Set Point"

screen. Adjust the knob clockwise to increase and counter-

clockwise to decrease the desired building pressure level. Press

the button again to return to the main screen. Replace the user

control cover.
Modulating CO

with Building Pressure Control Option —

This option will modulate the supply fan of the ERV based on

the building CO

level, and will modulate the exhaust airflow

to maintain the building pressure set point. Follow the proce-

dure outlined above to configure the minimum and maximum

outside airflow and CO

levels. After setting the maximum

level press the push button once more to display the build-

ing pressure set point screen. Adjust the knob clockwise to

increase and counterclockwise to decrease the desired building

pressure level. Press the button again to return to the main

screen. Replace the user control cover.

Operating Sequence —

When operation is called for

by the rooftop supply fan interlock or remote timer option, the

ERV supply blower(s), exhaust blower(s) and wheel motor will

be energized. The supply and exhaust blowers will provide the

adjusted/programmed airflow and the ERV wheel will rotate at

a constant speed unless influenced by one of the following con-

ditions. The sequence of operation is shown in Fig. 24.
LOW TEMPERATURE LOCKOUT — The optional low

temperature lockout function locks out the 62E ERV if the out-

door-air temperature entering the wheel is below the set point.

The low temperature lockout is factory set at –23.3 C (–10 F),

and can be field adjusted from –34.4 C to 37.8 C (–30 F to

100 F).
FROST PROTECTION — The frost protection option moni-

tors the pressure drop across the ERV wheel. If the pressure

drop rises above an adjustable limit, the outside air fan will be

de-energized for a 5-minute period. The setting must be field

set at 50% above (1.5 times) the pressure drop measured at the

maximum adjusted airflow and a clean, dry wheel.
ERV WHEEL VARIABLE FREQUENCY DRIVE

(VFD) — The ERV wheel VFD option monitors the pressure

drop across the ERV wheel. If the pressure drop rises above an

adjustable limit, the ERV wheel rotational speed will be re-

duced for a minimum of 5 minutes to defrost the wheel. The

setting must be field set at 50% above (1.5 times) the pressure

drop measured at the maximum adjusted airflow and a clean,

dry wheel.
PRE-HEATERS — Units may be equipped with electric pre-

heaters to prevent frost build-up on the wheel by slightly

warming the outdoor air. This feature monitors the pressure

drop across the ERV wheel and the outdoor-air temperature. If

the pressure drop rises above an adjustable limit and the out-

door-air temperature is below an adjustable set point, the heat-

ers will be energized. The wheel pressure drop setting must be

field set at 50% above (1.5 times) the pressure drop measured

at the maximum adjusted airflow and a clean, dry wheel. The

outdoor air thermostat is factory set to activate at –20.6 C

(–5 F), and can be field adjusted from –34.4 C to 37.8 C (–30 F

to 100 F).

Fig. 19 — Exhaust Air Offset Screen

387.eps

Fig. 20 — Modulating Cfm

a62-388.eps

Fig. 21 — Maximum Cfm Screen

a62-389.eps

Fig. 22 — Minimum CO

Screen

a62-390.eps

Fig. 23 — Maximum CO

Screen

a62-391.eps