A.O. Smith AWH-35, Instruction Manual

Page: 10 / 48

10
INSTALLATION REQUIREMENTS
Read all installation requirements in this manual before installation
begins. The installation must conform to these instructions and
all local and national code authority having jurisdiction.
Costs to diagnose, perform service and repair damage caused
by installation errors are not covered under the limited warranty.
Costs to correct installation errors are not covered under the
limited warranty.
WATER TEMPERATURE
MAXIMUM SYSTEM TEMPERATURE
The HPWH units covered in this manual are capable of
maintaining a maximum system/storage tank temperature of
140°F (60°C). Some commercial water heating applications
may require higher temperatures. Install a booster water heater
downstream from the storage tank for temperatures above
140°F (60°C). See Figure 8 on page 18.
INLET & OUTLET WATER TEMPERATURE
The inlet (entering) water temperature operating range for the
HPWH is 50°F to 140°F (10°C to 60°C). The water temperature
rise (Delta T - ∆T) through the condenser (heat exchanger) will
be approximately 8°F to 12°F (4°C to 7°C).
Outlet water temperatures up to 152°F (67°C) are possible
during normal operation. Exposure to water temperatures this
high can cause serious bodily injury or death. See Mixing Valves
and Table 5 on page 14.
Service & Installation Notes:
If the inlet (entering) water temperature is outside the operating
temperature range for extended periods the control system may
lock out on high or low refrigerant pressure switch events/trips.
When the control system locks out on a refrigerant pressure
switch event the compressor will stop running, the blower and
circulation pump (on models equipped with factory installed
pump) will continue to operate. This is a hard lock out condition.
The control system is manually reset by cycling power to the
HPWH off and then on again.
The tank thermostat must not be set any higher than 140°F
(60°C) to prevent control system lock outs.
Ground water temperatures can fall below 50°F (10°C) for
extended periods during winter months in many regions. For this
reason the cold water supply lines and should not be connected
directly to the HPWH inlet or T fitted into the inlet (return) water
piping. The cold water supply lines should be connected directly
to the storage tank only. See the Piping Diagrams on page 4 1
in this manual for more information.
AIR TEMPERATURE
ENTERING AIR TEMPERATURE
The return (entering) air temperature range of operation for
the unit is 50° - 95°F (10°C to 35°C). The air temperature drop
(Delta T - ∆T) through the evaporator (heat exchanger) will be
approximately 12°F to 20°F (7°C to 11°C).
If the entering air temperature is outside this operating range
the HPWH unit’s Ambient Air Limit Thermostat will discontinue
heating operation until the entering air temperature returns to this
operating range. See Figure 1 5 on page 37 .
High Ambient Air Kits are available that will allow the unit to
operate with entering air temperatures up to 120°F (49°C). These
accessory kits must be installed if entering air temperatures
exceed 95°F (35°C) for extended periods.
Contact your local distributor or call the technical support
phone number listed on the back cover of this manual for more
information on ordering one of these accessory kits.
Service & Installation Notes:
When the High Ambient Air kit is installed the heating stage set
point on the Ambient Air Limit thermostat must be raised to 120°F
(49°C) to allow heating operation up to this temperature.
LOCATING THE WATER HEATER
PROPERTY DAMAGE!
All water heaters eventually leak.
•
Do not install without adequate drainage.
•
CAUTION
INDOOR INSTALLATION ONLY
The HPWH unit is designed for indoor installation only.
Carefully choose a location for the HPWH unit. Placement is a
very important consideration for optimal performance and safety.
Locate the HPWH near a floor drain. The unit should be located
in an area where leakage from the HPWH unit or the storage tank
it is connected to will not result in damage to the area adjacent
to the water heater or to lower floors of the structure. See Unit
Placement on page 16.
FREEZING TEMPERATURES
The HPWH unit must not be installed in space where freezing
temperatures will occur. Exposure to freezing ambient
temperatures below 32°F (0°C) may result in severe damage to
internal components. Damage caused by exposure to freezing
temperatures is not covered under the limited warranty.
COASTAL REGIONS
When the HPWH will be installed within 5 miles of a seacoast the
optional Corrosive Duty Package is required. The corrosive duty
package includes a 316 stainless steel cabinet and a phe nolic
coating applied to the evaporator and blower. Damage caused to
units not equipped with the corrosive duty package in coastal
regions is not covered under the limited warranty.
HEAT SOURCE
The HPWH unit should be located where there is an adequate
source of ambient heat and where the cooling benefit can be
utilized when possible.
If installation in a space with an adequate heat source is not
possible the HPWH unit can be ducted to/from another space
such as a boiler room or to the outdoors where sufficient heat is
available. See Air Flow and Ducting on page 19.
CONDITIONED SPACE
When installed in a conditioned space ducting supply (outlet) air
to an alternate location may be necessary to avoid over-cooling
of the space where the HPWH is installed or provide spot cooling
in areas for comfort and/or to offset cooling load. See Building Air
Pressure , Air Flow and Ducting on page 19.