Bryant 674B User Manual
User Information Manual
674B
SINGLE-PACKAGED GAS HEAT/ELECTRIC
HEAT PUMP UNIT WITH
PURON® (R-410A) REFRIGERANT
Cancels: New OM10–21
1–04
NOTE: Read the entire instruction manual before starting the
installation.
SAFETY CONSIDERATIONS
Note to Installer: This manual should be left with the equipment
user.
Installation and servicing of air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only
trained and qualified personnel should install, repair, or service
air-conditioning equipment.
Untrained personnel can perform basic maintenance functions of
cleaning coils and filters. All other operations should be performed
by trained service personnel. When working on air-conditioning
equipment, observe precautions in the literature, tags, and labels
attached to the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloth for unbrazing operations. Have fire extinguisher
available for all brazing operations.
WARNING: Improper installation, adjustment, alteration, service, maintenance, or use can cause carbon
monoxide poisoning, fire, or an explosion which could
result in personal injury or unit damage. Consult a
qualified installer, service agency, or gas supplier for
information or assistance. The qualified installer or
agency must use only factory-authorized kits or accessories when modifying this product.
severe personal injury or death. WARNING signifies a hazard
which could result in personal injury or death. CAUTION is used
to identify unsafe practices which would result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
These instructions cover minimum requirements and conform to
existing national standards and safety codes. In some instances,
these instructions exceed certain local codes and ordinances,
especially those that may not have kept up with changing residential construction practices. We require these instructions as a
minimum for a safe installation.
UNIT INTRODUCTION
This 674B unit is a small packaged gas heat/electric heat pump
system that can utilize both the efficiency of heat pump heating
and the comfort of gas heating. The system will optimize for ideal
heating, depending on several factors. This unit uses Puron®, the
ozone friendly refrigerant for cooling and heat pump heating.
WARNING: Before performing service or maintenance
operations on unit, turn off gas supply to unit. Then turn
off unit main power switch. Electrical shock or explosion
could cause serious injury or death.
WARNING: Do not store or use gasoline or other
flammable vapors and liquids in the vicinity of this or any
other appliance. Failure to follow this warning could
result in fire, serious injury, or death.
WARNING: Do not use this unit if any part has been
under water. Immediately call a qualified service technician to inspect the unit and to replace any part of the
control system which has been under water. Failure to
follow this warning could result in electrical shock, fire,
serious injury, or death.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol in instructions or manuals, be alert to
the potential for personal injury.
Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious hazards which will result in
C99088
Fig. 1—Unit 674B
Starting or Shutting Unit Off
1. To start the unit:
a. Turn on the electrical and gas power supply to unit.
b. Select desired temperature on thermostat and set SYS-
TEM switch or MODE control to desired mode.
2. To shut unit off:
NOTE: If the unit is being shut down because of a malfunction,
call your dealer as soon as possible.
a. Set system SWITCH or MODE control to OFF.
b. Turn off the electrical power, install lock-out tag and
shut off gas supply to unit.
—1—
OPERATING YOUR UNIT
The operation of your system is controlled by the indoor temperature control (for 674B, either a Thermidistat™ or dual fuel
thermostat is required). You simply adjust the thermostat and it
maintains the indoor temperature at the level you select. Most
thermostats of heating and cooling systems have 3 controls: a
temperature control selector, a FAN control, and a SYSTEM or
MODE control. Refer to your thermostat owner’s manual for more
information.
To better protect your investment and to eliminate unnecessary
service calls, familiarize yourself with the following facts:
1. During heat pump heating, increasing the thermostat setting
more than 2°F may cause the supplemental gas heat to be
turned on for a short period oftimetosatisfy the thermostat.
Needless use of the supplementary heat reduces potential
energy savings.
2. Ice or frost tends to form on the coil during winter heating
operation. Your heat pump is designed to automatically
melt the ice. When in this defrost cycle, it is normal for
steam or fog to rise from the outdoor unit. Do not be
alarmed!
I. COOLING MODE
With the SYSTEM or MODE control set to COOL, your unit will
run in cooling mode until the indoor temperature is lowered to the
level you have selected. On extremely hot days, your unit will run
for longer periods at a time and have shorter “off” periods than on
moderate days.
II. HEAT PUMP HEATING MODE
With the SYSTEM or MODE control of your indoor thermostat set
to HEAT, your unit will run in heat pump heating mode until room
temperature is raised to the level you have selected. Of course,
your system will run for longer periods to maintain a comfortable
environment on cooler days and nights than on moderate ones.
III. GAS HEAT MODE
Your heat pump is your primary heating source. Your system is
also be equipped with a supplemental gas heating source. On cold
days and nights, your system will automatically turn on the
supplemental heat in order to maintain the level of comfort you
have selected.
When your heat pump needs additional heat to keep you comfortable, your Bryant electronic thermostat will turn on the supplemental gas heat and display the “AUX HT” message.
IV. DEFROST MODE
When your heat pump is providing heat to your home or office and
the outdoor temperature drops below 45°F, moisture may begin to
freeze on the surface of the coil. If allowed to build up, this ice
would impede airflow across the coil and reduce the amount of
heat absorbed from the outside air. So, to maintain energy-efficient
operation, your heat pump has an automatic defrost mode.
The defrost mode starts at a preset time interval of 30 minutes,
although, it may be reset to 60, 90 or 120 minutes. Defrost will
start at the preset time only if the ice is sufficient to interfere with
normal heating operation.
After the ice is melted from the coil, or after a maximum of 10
minutes in defrost mode, the unit automatically switches back to
normal heating operation.
Do not be alarmed if steam or fog appears at the outdoor unit
during defrost mode. Water vapor from the melting ice may
condense into a mist in the cold outside air.
During certain weather conditions such as heavy snow and
freezing rain it is not uncommon for ice to build up on the unit
grille. This is normal for these weather conditions. Do not attempt
to remove the ice from the unit grille. This condition will not affect
the proper function of the unit and will clear within a few days.
V. EMERGENCY HEAT MODE
If you should have problems with the heat pump portion of your
system, this mode allows your supplemental gas heating source to
keep your home or office warm until your heat pump can be
serviced.
MAINTENANCE AND SERVICE
This section discusses maintenance that should be performed on
your system. Most maintenance should be performed by your
dealer. You, as the owner, may wish to handle some minor
maintenance for your new unit.
A. Routine Maintenance
All routine maintenance should be handled by skilled, experienced
personnel. Your dealer can help you establish a standard procedure.
For your safety, keep the unit area clear and free of combustible
materials, gasoline, and other flammable liquids and vapors.
To assure proper functioning of the unit, flow of condenser air
must not be obstructed from reaching the unit. Clearance from the
top of the unit is 48 in. Clearance of at least 36 in. is required on
sides except the power entry side (42 in. clearance) and the duct
side (12 in. minimum clearance).
B. Maintenance and Care for the Equipment Owner
Before proceeding with those things you might want to maintain
yourself, please carefully consider the following:
WARNING: 1. TURN OFF ALL ELECTRICAL
POWER TO YOUR UNIT AND INSTALL LOCK-OUT TAG BEFORE
SERVICING OR PERFORMING
MAINTENANCE. ELECTRIC
SHOCK COULD CAUSE SERIOUS
INJURY OR DEATH.
2. When removing access panels or performing maintenance functions inside your unit, be aware of sharp
sheet metal parts and screws. Although special care is
taken to keep sharp edges to a minimum, be extremely
careful when handling parts or reaching into the unit.
AIR FILTERS
The air filter(s) should be checked at least every 3 or 4 weeks and
changed or cleaned whenever it becomes dirty. Dirty filters
produce excessive stress on the blower motor and can cause the
motor to overheat and shut down.
This unit must have air filters in place before it can be operated.
These filters can be located in one of at least two places. In many
applications the installer will provide return air filter grilles
mounted on the wall or ceiling of the conditioned structure. In the
instance of filter grilles, the filters can simply be removed from the
grille and replaced.
The other typical application is an accessory filter rack installed
inside the unit itself. The following information is given to assist
in changing filters used in these internal filter racks.
Table 1 indicates the correct filter size for your unit. Refer to Fig.
2 to access filters installed in the accessory filter rack.
TABLE 1—INDOOR-AIR FILTER DATA
UNIT SIZE FILTER SIZE
674B024-030 20x20x1
674B036 20x24x1
674B042-060 24x30x1
To replace or inspect filters in accessory filter rack (See Fig. 2):
—2—
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