A.O. Smith AWH-35, Instruction Manual

Page: 14 / 48

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connected to the storage tank. If more than one water heating
appliance is connected to the storage tank the aggregate total
of all heating input ratings of all connected appliances must be
factored when choosing a T&P valve for the storage tank.
The pressure rating of the T&P valve should always be rated
equal to or below the working pressure rating of the storage tank
or water heater, whichever rating is lower.
Contact the manufacturer of the storage tank for assistance in
sizing of a temperature and pressure relief valve. Follow the
storage tank manufacturer’s instructions regarding the proper
installation of these products.
TANK SELECTION
The HPWH unit is not an instantaneous water heater and must
be connected to a storage tank. Storage tank configurations must
meet these criteria:
1. The HPWH must not be connected directly to a standard gas
or electric water heater.
2. If the HPWH is connected to a used storage tank, the tank
should be thoroughly cleaned of scale and sediment before
the HPWH is installed.
3. Connection ports used on the storage tank must permit the
recommended flow rate through HPWH. The connection
ports used on the storage tank must not be smaller than the
inlet outlet connection sizes on the HPWH unit. See Table 4
on page 13.
4. Water heated by the HPWH should be returned to the tank at
a location that is above the level of the tank’s cold water inlet
and/or the heat pump’s inlet source.
5. The HPWH unit’s inlet and outlet lines to the storage tank
should be dedicated. Example: no other line (such as a
building re-circulating loop or cold water supply) should be
connected to the HPWH unit’s inlet or outlet water lines.
SOLAR TANKS
Solar tanks should be used with caution. Some solar tanks with
top connections have dip tubes which may significantly reduce
the efficiency performance of the HPWH unit.
Before using any solar tank in this application, contact your
representative or call the toll free technical support number on
the back cover of this manual for further assistance.
CONTAMINATED AIR
Do not duct air from a garage or other
space where potentially harmful fumes
from solvents, chemicals or exhaust
from automobiles are present into any
other space in the building structure.
Gas and carbon monoxide detectors
are available.
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
Breathing Hazard - Carbon Monoxide Gas
The supply (outlet) air from a HPWH installed in a garage or a
unit drawing return (inlet) air from a garage or any area where
solvents or other chemicals that emit potentially harmful fumes
are stored or automobiles are located must never be ducted to
any other space inside the building structure. This would include
all occupied and unoccupied spaces such as attics or basements.
TABLE 5
Water Temperature
Time to Produce 2nd & 3rd
Degree Burns on Adult Skin
180°F (82°C) Nearly instantaneous
170°F (77°C) Nearly instantaneous
160°F (71°C) About 1/2 second
150°F (66°C) About 1-1/2 seconds
140°F (60°C) Less than 5 seconds
130°F (54°C) About 30 seconds
120°F (49°C) More than 5 minutes
CONDENSATE REMOVAL
The HPWH unit produces condensate which must be discharged.
If there is no drain easily accessible, a condensate lift pump must
be installed to discharge the condensate to a remote location. See
Condensate Drain Line on page 18 for installation instructions.
CONTAMINATED WATER
Connecting the heat pump to any system other than a water
system may lead to premature corrosion of the unit's heat
exchanger and void the unit warranty.
Corrosive Chemical Hazard
•
This HPWH unit must not be used to heat any fluid other than
water. Corrosive chemicals must not be introduced into the
waterways in this HPWH unit.
TEMPERATURE - PRESSURE RELIEF VALVE
Explosion Hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASME code.
Properly sized temperature-
pressure relief valve must be
installed in the designated
opening in the storage tank.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.
This heat pump water heater should only be connected to a
storage tank with a properly rated/sized and certified combination
temperature - pressure relief valve. The valve must be certified by
a nationally recognized testing laboratory that maintains periodic
inspection of production of listed equipment of materials as
meeting the requirements for Relief Valves for Hot Water Supply
Systems, ANSI Z21.22 • CSA 4.4, and the code requirements of
ASME.
When the HPWH unit is connected to a storage tank a temperature
and pressure relief valve must be installed in the designated
opening for the T&P valve per the storage tank manufacturer’s
requirements. The T&P valve’s Btu/hr rating must be equal to
or greater than the total heating input rating of all water heaters