Aprilaire 8355 User manual

Important Safety Information Warning:

•Always turn off power at the main power source by unscrewing

fuse or switching circuit breaker to the off position before installing,

removing, cleaning, or servicing thermostat.

•Read all of the information in this manual before installing or

programming this thermostat.

•This is a 24V AC low-voltage thermostat. Do not install on voltages

higher than 30V AC.

•All wiring must conform to local and national building and electrical

codes and ordinances.

•Do not short (jumper) across terminals on the gas valve or at the

system control to test installation. This will damage the thermostat

and void the warranty.

7 Day Programmable

2 Heat / 2 Cool

Heat Pump

MODEL 8355

User’s Manual

Installation and

Programming

ELECTRONIC THERMOSTATS

Features

• Four pre-programmed setpoints for each day of the week.

• Fast and easy programming for setting all days of the week

simultaneously.

• Energy efficient recovery.

• Residual cooling for added air-conditioning efficiency.

• Two “AA” ENERGIZER brand batteries retain program memory,

even during power outages.

• Low battery indicator.

• Multi-colored LED indicators for system status.

• Zone compatible as master thermostat.

• Fahrenheit/Celsius display option.

• Programmable from 45°F (7°C) to 90°F (32°C).

• Accuracy within ±1 degree.

• Adjustable temperature differential: 1-3 degrees.

• Maintains summer and winter programming.

Replacing Existing Thermostat

1. Turn off power to heating and cooling system.

2. Remove cover of old thermostat to expose wires. Do not

disconnect wires. (Fig. 1)

3. Label wires per Table 1.

TABLE 1

Old Label New Label Description

R, V-VR or VR-R R 24 VAC

Y, Y1 or M Y1 Stage 1 Cooling/Heating Circuit

O or R O Reversing Valve (Cooling Mode)

B B Reversing Valve (Heating Mode)

G or F G Fan Contactor Circuit

Y2 Y2 2nd Stage Cooling Circuit

W1 or W2 or W-U W2 2nd Stage Heating Circuit

L or X L System Monitor LED

E E Emergency Heating Circuit

C, X or B C 24 VAC, Transformer Common Side

NOTE: This thermostat requires a 24V AC common wire for proper operation.

4. After labeling wires, remove wires from terminals.

5. Remove existing thermostat base from wall.

6. Refer to the following section for instructions on how to

install thermostat.

FIGURE 1

Installing the Model 8355 Thermostat

NOTE: For new installations, mount thermostat on inside wall, 4-5 feet

above the floor. Do not install behind a door, in a corner, near air vents, in

direct sunlight, or near any heat or steam generating fixtures. Installation

at these places will affect thermostat operation.

IMPORTANT: This thermostat is compatible with 100% lockout systems. To

reset the system, turn thermostat to OFF position for at least 60 seconds.

1. Turn power off to the heating and cooling systems.

2. Place COOL-OFF-HEAT-EM in OFF position.

3. Place FAN: AUTO-ON switch

into AUTO position.

4. Remove the cover using a coin

or screwdriver.

FIGURE 2

5. Place thermostat against the wall at desired location. Make sure

wires will feed through opening on base of thermostat.

6. Mark placement of mounting holes. See Fig. 3. Set base aside.

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

FAN: AUTO-ON

COOL-OFF-HEAT-EM

FIGURE 3

7. Drill the marked holes using a 3/16" drill bit. NOTE: Enclosed plastic

anchors do not require a drilled hole for drywall.

8. Tap plastic anchors into the holes.

9. Align base with plastic anchors and feed wires through opening.

See Fig 4. FIGURE 4

10. Secure base to wall with supplied screws.

11. Connect wires to terminal strip. Refer to wiring diagrams on other

side of this sheet. Make sure wire connections are secure.

12. Install two "AA" ENERGIZER brand batteries or equivalent into

battery compartment. Be sure to match positive (+) ends of batteries

with positive (+) battery terminals in the battery compartment.

13. Replace cover onto thermostat by snapping into place.

14. Turn on power to system. Test thermostat as described in the

following section.

PROGPROG

MANMAN

FAN AUTO ONFAN AUTO ON

COOL OFF HEAT EMCOOL OFF HEAT EM

CHANGECHANGE SETSET PROG/MANPROG/MAN

AMAM

PMPM

MORN DAY EVE NITE EER

C L RC L R

MOUNTING HOLES

PROGPROG

MANMAN

FAN AUTO ONFAN AUTO ON

COOL OFF HEAT EMCOOL OFF HEAT EM

CHANGECHANGE SETSET PROG/MANPROG/MAN

AMAM

PMPM

MORN DAY EVE NITE EERMORN DAY EVE NITE EER

C L RC L R

OPENING

Programming Guide

Set Time of Day, Day of Week,

Temperature Differential, Residual Cooling

1. Press SET & PROG/MAN.

Release simultaneously.

Press or to change

Time of Day.

2. Press 3. Press

To Change Day of Week

4. Press 5. Press

To change 1st Stage

Temperature Differential

NOTE: The Temperature Differential is Factory preset at 1°. This means

that whenever the room temperature changes by one full degree from

the temperature setting, the system will turn on. If the system turns on

too often, increase the temperature differential.

6. Press 7. Press

To change 2nd Stage

Temperature Differential

NOTE: The Second Stage Temperature Differential is Factory preset at 2°.

8. Press 9. Press

To change

Residual Cooling

NOTE: The residual cool feature will keep the system fan on for an

additional 30, 60 or 90 seconds after the compressor cycles off in cool

mode. The residual cool feature can only be set in the cool mode.

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

SET PROG/MAN

SET P

1=MO

2=TU

3=WE

4=TH

5=FR

6=SA

7=SU

SET P

SET

Changing Fahrenheit (F) to Celsius (C)

Press and Hold SET Press

Release both simultaneously.

Energy Efficient Recovery

The energy efficient recovery feature looks ahead up to 2 hours prior to the

end of the setback (or set-up) period to begin monitoring performance and

calculating when to turn on your system. It also determines whether the aux-

iliary heat or cool stages should be activated prior to setpoint time to meet

your chosen setpoint temperature. The thermostat will indicate “EER” in the

display when this program feature is active. The energy efficient recovery

feature will lockout the auxiliary stages until 20 minutes prior to upcoming

setpoint time to utilize the most energy efficient first stage. The auxiliary

stages of heating and cooling will be available during this lock-out period

to maintain the setpoint temperature should the system not be able to

keep up with the heating or cooling demand.

Simple Programming Mode

1. Place COOL-OFF-HEAT-EM

in COOL or HEAT position.

2. Press & Hold SET. Press the button.

Release simultaneously.

3. The MORN indicator should be blinking. Program the Time-of-Day and

the temperature as outlined in the Setting Daily Program section.

NOTE: Use this function to set all 7 days of the week with the same program.

SET P

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

SET P

COOL-OFF-HEAT-EM

Setting Daily Programming

1. Place COOL-OFF-HEAT-EM

in COOL position.

2. Press SET button. The display will show a

number from 1 to 7. This number represents

the day of the week to be programmed. If

programming individual days, press either

or button to adjust the day of the week

to program (1=Mon., 2=Tues., etc.).

3. Press SET. Press or to change MORN time.

4. Press SET.

5. Press or to change

MORN temperature.

6. Repeat Steps 2-5 for DAY, EVE, and NITE.

7. Press SET to finish this day.

8. Repeat steps 2–7 above to program

any other day of the week.

9. Shift COOL-OFF-HEAT-EM to HEAT position.

10. Repeat steps 2-7 to program HEAT (winter) settings.

Begin Programmed Operation

1. Place FAN: AUTO-ON

into AUTO.

2. Place COOL-OFF-HEAT-EM

into COOL or HEAT,

depending upon the season.

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

COOL-OFF-HEAT-EM

SET PR

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

SET PR

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

FAN: AUTO-ON

SUMMER

WINTER

COOL-OFF-HEAT-EM

3. Press PROG/MAN button

until indicator is in PROG position.

Temporary Program Override

To temporarily increase or decrease temperature

Press or

The thermostat will automatically return to the program at the next

scheduled setting change or after four hours.

Manual Operation

Manual operation allows continuous override of the program settings.

1. Press PROG/MAN until indicator is in MAN position.

2. Press or to adjust

temperature settings.

Reset

To reset the thermostat

to factory pre-programmed

conditions, press the reset

button located directly to

the right of the display.

ET PROG/MAN C

PROG

MAN

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

T PROG/MAN

PROG

MAN

PROG

MAN

SET PROG/MAN COOL-OFF-HEAT-EM

AUX CHECK EMER

FAN: AUTO - ON

PROG

MAN

FAN AUTO ON

COOL OFF HEAT EM

CHANGE SET PROG/MAN

MORN DAY EVE NITE EER

RESET BUTTON

C L R

NOTE: While in the Cool or Heat mode, once the thermostat turns the system

off, a built-in delay keeps the compressor from turning on for about 5 minutes.

This protects the compressor. No additional time delay relay (delay on break)

is necessary.

To Test Thermostat

WARNING: DO NOT SHORT (JUMPER) ACROSS TERMINALS OF GAS

VALVE OR SYSTEM CONTROL TO TEST OPERATION. THIS WILL DAMAGE

THE THERMOSTAT AND VOID YOUR WARRANTY.

CAUTION: Do not switch system to cool if the temperature is below

50°F (10°C). This can damage the air conditioning system and cause

personal injury.

1. Place the COOL-OFF-HEAT-EM

switch into the COOL position

2. Press the button until the temperature

setting is at least 3 degrees below the room temperature. The air

conditioning system should turn on within a few seconds.

NOTE: While in the Cool or Heat mode once the thermostat turns the system

off, a built-in delay keeps the compressor from turning on for about 5 minutes.

This protects the compressor. No additional time delay relay (delay on break)

is necessary.

3. Put the COOL-OFF-HEAT-EM switch into

the OFF position. The air conditioning

system should turn off. The fan may

continue to run for a short period of time.

4. Put the COOL-OFF-HEAT-EM switch

into the HEAT position.

5. Press the button until the temperature setting is at least

3 degrees above room temperature. The heating system should turn

on. The fan may not turn on immediately, depending upon the fan

delay built into the furnace.

6. Put the COOL-OFF-HEAT-EM switch

into the OFF position. The heating

system should turn off. Once again,

the fan may have a delay.

7. Put the FAN: AUTO-ON switch

to the ON position. The blower

fan should turn on.

8. Put the FAN: AUTO-ON switch

to the AUTO position. The blower

fan should turn off.

LED Indicators

The LED indicators are used to indicate system activity. The AUX indicator

illuminates during a call for second stage heating. The auxiliary stages are

used to maintain comfort during extremes in weather conditions. If the

AUX LED is illuminated too frequently during periods of moderate temper-

ature, check the differential settings (page 5).

The CHECK indicator is used to monitor system status. If the CHECK

indicator is illuminated, call your local HVAC service provider.

The EMER indicator is illuminated only when the system switch is moved

to the EM, emergency heat position. The EM position is only used when

the primary stage of heat is not functioning or requires service.

COOL-OFF-HEAT-EM

FAN: AUTO - ON

FAN: AUTO-ON

Troubleshooting

SYMPTOM REMEDY

Thermostat does not turn

on system.

Check Wiring

(see INSTALLATION).

Check fuse. Replace with 3 amp

fuse if fuse has opened. Five

minute compressor short cycle

protection may be in effect. Press

RESET to override. NOTE: This will

erase programming.

Thermostat turns on and off too

frequently.

Increase Temperature Differential

(see PROGRAMMING).

Display is blank, flashing or

constant "LO BAT."

Replace batteries.

Time shown on display is not the

current time of day.

Change time of day setting

(see PROGRAMMING).

Thermostat does not follow

program.

Thermostat in MANUAL mode

(see PROGRAMMING).

Thermostat may not have been

programmed in HEAT or COOL

position. Verify program.

Check AM/PM indicators at time

of day and programmed time

changes (see PROGRAMMING).

Verify program and day of week

is correct (see PROGRAMMING).

Thermostat does not advance day

of week.

To view or change day of week

use method on page 5.

If problems with thermostats cannot be solved, call:

Technical Support: 608-257-8801

Monday-Friday 7:45 am-5:00 pm CST

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