Limited warranty, Operation, Changing temperature differential – Aprilaire 8334 User Manual

Page 2: Troubleshooting, Wiring diagrams, Changing fahrenheit (f) to celsius (c), Your research products corporation aprilaire

Operation

Setting or Changing the Setpoint Temperature

1. Press either the

button.

The display will show the current
temperature setpoint.

2. Press either the

button

to adjust the temperature setting
either up or down.

The display will return to the room temperature display five seconds after
the last input and the new setpoint will be saved.

Changing Temperature Differential

IMPORTANT: The temperature differential is factory set at 1 (.5°). This
means that whenever the room temperature changes by one half of a
degree from the temperature setting, the system will turn on. If the
system turns on too often, increase the temperature differential.

1. Press

both and buttons

at the same time and hold for one
second.

2. Press either the

button

to adjust the temperature
differential up or down.

The display will show:

The display will return to the room temperature
five seconds after the last input.

TROUBLESHOOTING

Symptom Remedy

Hot

Heating

Control

Fan

Control

Cooling
Control

(COOLING)

Transformer

(HEATING)

Transformer

H
E
R

M
O

S
T
A
T

H
E
R

M
O

S
T
A
T

H
E
R

M
O

S
T
A
T

24 VAC

120 VAC

Hot

Heating

Control

Fan

Control

Transformer

24 VAC

120 VAC

H
E
R

M
O

S
T
A
T

Hot

Heating

Control

Heating

Control

Transformer

24 VAC

120 VAC

Hot

120 VAC

Hot

120 VAC

HEAT/COOL

4-WIRE

SINGLE TRANSFORMER

HEAT ONLY

2-WIRE

SINGLE TRANSFORMER

HEAT ONLY

3-WIRE

SINGLE TRANSFORMER

Factory-Installed

jumper

Factory- Installed

jumper

H
E
R

M
O

S
T
A
T

Hot

Cooling
Control

Fan

Control

Transformer

24 VAC

120 VAC

COOL ONLY

3-WIRE

SINGLE TRANSFORMER

HEAT/COOL

5-WIRE

TWO TRANSFORMER

NOTE: Both transformers
must be in phase.

Cooling
Control

Fan

Control

NOTE: Cut center of
factory installed jumper
and bend back

NOTE: Remove factory
installed jumper

Wiring Diagrams

The following is just a sample of the most common types of HVAC systems.
Refer to your systems installation manual for wiring information.

Thermostat does not turn
on system

Check Wiring
(see INSTALLATION).

Check fuse. Replace with 2 amp
fuse if fuse has opened.

Thermostat turns on and
off too frequently.

Increase Temperature Differential
(see DIFFERENTIAL).

Display is blank, flashing
or constant “LO BAT”.

Replace batteries.

System fan does not
operate properly.

Move fan option switch to either
gas or electric, to match system
(see INSTALLATION).

Thermostat does not display
proper room temperature.

Check “F” Fahrenheit/”C” Celsius
switch located at top center of
circuit board for proper position.
If a new selection is made, press
“RESET” button located directly
below LCD display.

Limited Warranty

Your Research Products Corporation Aprilaire

Thermostat unit is expressly

warranted for two (2) years from date of installation to be free from defects in
materials and workmanship.

Research Products Corporation’s exclusive obligation under this warranty
shall be to supply, without charge, a replacement for any thermostat which is
found to be defective within a two (2) year period and which is returned,
together with the date of installation, no later than thirty (30) days after said
two (2) year period by you to either your original supplier or to Research
Products Corporation, Madison, Wisconsin 53701.

THIS WARRANTY SHALL NOT OBLIGATE RESEARCH PRODUCTS CORPO-
RATION FOR ANY LABOR COSTS AND SHALL NOT APPLY TO DEFECTS IN
WORKMANSHIP OR MATERIALS FURNISHED BY YOUR INSTALLER AS
CONTRASTED TO DEFECTS IN THE THERMOSTAT ITSELF.

IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PAR-
TICULAR PURPOSE SHALL BE LIMITED IN DURATION TO THE AFORESAID
TWO YEAR PERIOD. RESEARCH PRODUCTS CORPORATION’S LIABILITY
FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, OTHER THAN DAMAGES
FOR PERSONAL INJURIES, RESULTING FROM ANY BREACH OF THE AFORE-
SAID IMPLIED WARRANTIES OR THE ABOVE LIMITED WARRANTY IS
EXPRESSLY EXCLUDED. THIS LIMITED WARRANTY IS VOID IF DEFECT(S)
RESULT FROM FAILURE TO HAVE THIS THERMOSTAT INSTALLED BY A
QUALIFIED HEATING AND AIR CONDITIONING CONTRACTOR. IF THE
LIMITED WARRANTY IS VOID DUE TO FAILURE TO USE A QUALIFIED
CONTRACTOR, ALL DISCLAIMERS OF IMPLIED WARRANTIES SHALL BE
EFFECTIVE UPON INSTALLATION.

Some states do not allow limitations on how long an implied warranty lasts or
the exclusion or limitation of incidental or consequential damages, so the
above exclusion or limitations may not apply to you.

This warranty gives you specific legal rights and you may also have other
rights which vary from state to state.

P.O. BOX 1467 • MADISON, WI 53701-1467

Products For Better Indoor Air Quality

™

B2202515 REV. 12/00

COOL OFF HEAT

FAN: AUTO - ON

COOL OFF HEAT

FAN: AUTO - ON

Changing Fahrenheit (F) to Celsius (C)

The thermostat is preset to display the temperature in degrees
Fahrenheit. You may change the display readout to Celsius if desired.

1. Move the manual switch marked “F” (Fahrenheit) and “C” (Celsius)

located at the top center of the circuit board to the desired setting.

2. Press RESET button located lust below the LCD display to register

the change.

The display will change to show the temperature in your desired
temperature scale. To return the thermostat to its original setting,
repeat steps 1 and 2 above.

If problems with thermostat cannot be solved, call:

Technical Support: 608-257-8801

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

Differential

Setting

Degrees

1°F/.5°C

2°F/1.0°C

3°F/1.5°C

Hot

Fan

Relay

Transformer

24 VAC

120 VAC

HEAT PUMP WITH

COOL ACTIVE

REVERSING VALVE

H
E
R

M
O

S
T
A
T

Pre-Installed jumper

Compressor

Contactor

Reversing

Valve

Hot

Fan

Relay

Transformer

24 VAC

120 VAC

HEAT PUMP WITH

HEAT ACTIVE

REVERSING VALVE

H
E
R

M
O

S
T
A
T

Pre-Installed jumper

Compressor

Contactor

Reversing

Valve

NOTE: Installer must place jumper
between “W” and “Y” terminals.

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 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: When in the COOL mode (or HEAT and COOL for single stage
heat pumps), once the thermostat turns off, a built in 5-minute delay
prevents the system from turning on again. This protects the compressor.
No additional time delay relay is required.

3. Put the COOL-OFF-HEAT switch

into the OFF position. The air
conditioning system should turn off.

4. Put the COOL-OFF-HEAT 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 switch

into the OFF position. The heating
system should turn off. The fan may
continue to run for a short period
of time.

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.

COOL OFF HEAT

FAN: AUTO - ON