John Wood Takagi - 240H-340H-540H - Manual (Page 40)

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Page
FLOW
• This unit comes equipped with heating blocks to protect it against damages associated with freezing.
• 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.
• The freeze protection system will activate when the surrounding and/or outside temperatures drop
below 2.5 °C (36.5 °F).
• For the T-H3J-DV / 240H , T-H3S-DV / 340H and T-H3-DV / 540H models:
• In any areas subject to freezing temperatures, the manufacturer highly recommends an indoor
installation with an indoor 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.
• The manufacturer also highly recommends the use of a backflow vent damper (sold
separately) to minimize the amount of cold air entering through the exhaust venting when the
water heater is off.
• It is the installer’s responsibility to be aware of freezing issues and take all preventative measures. The
manufacturer will not be responsible for any damage to the heat exchanger as a result of freezing.
• If you will not be using your heater for a long period of time:
1. Completely drain the water out of the unit. Refer to p. 41
2. Disconnect power to your heater.
This will keep your unit from freezing and being damaged.
Normal Operation
Owner's Guide
Appliance/Use
Flow rate
GPM (US) L/min
Lavatory Faucet 1.0 3.8
Bath Tub 4.0 – 10.0 15.2 - 37.8
Shower 2.0 7.5
Kitchen Sink 1.5 5.6
Dishwasher 1.5 5.6
Washing machine 4.0 15.2
Household Flow Rates
Taken from UPC 2006
• The flow rate through the water heater is limited to
a maximum of 25 L/min (6.6 GPM) for the T-H3J-DV
/ 240H, 30 L/min (8.0 GPM) for the T-H3S-DV / 340H,
and 38 L/min (10.0 GPM) for the T-H3-DV / 540H.
• The temperature setting, along with the supply
temperature of the water will determine the flow
rate output of the unit.
• Please refer to the temperature vs. gallons per
minute charts on p. 54 to determine the likely flow
rates based on your local ground water temperature
and your desired outlet water temperature.
• Refer to the table to the top right for typical
household plumbing fixture flow rates to determine
what the water heater can do in a household
application.
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
FREEZE PROTECTION SYSTEM
• Based on the Can/CSA P.7 test method for
measuring energy loss of gas-fired instantaneous
water heaters, the water heater is rated for liters
per minute (L/min) (gallons per minute (GPM)) for
Natural Gas and Propane, when raising the water
temperature by 43 C° (77 F°) (from 14 °C to 57 °C
(58 °F to 135 °F)). See the chart on the right.
Unit: L/min (GPM)
Model Flow rate
T-H3J-DV / 240H 15.1 (4.0)
T-H3S-DV / 340H 16.7 (4.4)
T-H3-DV / 540H 18.5 (4.9)