Flow - Takagi T-H2-DV Installation Manual And Owner's Manual

x The flow rate through the T H2 DV/T H2 OS is limited to a maximum of 9.0 GPM.
x The temperature setting, along with the supply temperature of the water will determine the flow
rate output of the unit.
x Please refer to the temperature vs. gallons per minute chart on p. 50 to determine the likely flow
rates based on your local ground water temperature and your desired outlet water temperature
combination.
x Based on the United States Department of Energy
method of testing water heater output, the T H2 DV/T
H2 OS is rated for 285 gallons per hour (GPH) or 4.8
gallons per minute (GPM) for Natural Gas, and 285 GPH
or 4.8 GPM for Liquid Propane, when raising the water
temperature by 77qF (from 58qF to 135qF).
x Refer to the chart to the right for typical household
plumbing fixture flow rates to determine what the T H2
DV/T H2 OS can do in a household application.
x This unit comes equipped with heating blocks to protect it against damages associated with freezing.
x For this freeze protection system to operate there has to be electrical power to the unit. Damage to
the heat exchanger caused by freezing temperatures due to power loss is not covered under the
warranty. In cases where power losses can occur, consider the use of a backup power supply.
x The freeze protection system will activate when the surrounding and/or outside temperatures drop
below 36.5°F (2.5°C).
x In any areas subject to freezing temperatures, TAKAGI highly recommends an indoor installation with
the T H2 DV model. In such an installation, freezing issues can only occur if cold air enters through
the venting into the heat exchanger, whether by negative pressures within the installation location or
by strong outside winds. It is the installer's responsibility to be aware of these issues and take all
preventative measures. TAKAGI will not be responsible for any damage to the heat exchanger as a
result of freezing.
x TAKAGI also highly recommends the use of a back flow vent damper to minimize the amount of cold
air entering through the exhaust venting when the water heater is off.
x If you will not be using your heater for a long period of time:
1. Completely drain the unit of water. Refer to p. 40.
2. Disconnect power to your heater.
This will keep your unit from freezing and being damaged.
Only pipes within the water heater are protected by the freeze protection
system. Any water pipes (hot or cold) located outside the unit will not be
protected. Properly protect and insulate these pipes from freezing.
CAUTION

FLOW

FREEZE PROTECTION SYSTEM
39
Appliance / Use
Lavatory Faucet
Bath Tub
Shower
Kitchen Silk
Dishwasher
Washing machine
Taken from UPC 2006
Page
Normal Operation
Household Flow Rates
Flow Rate (GPM)
1.0
4.0 – 10.0
2.0
1.5
1.5
4.0