John Wood Takagi - 320H-520H - Manual (Page 3)

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SPECIFICATIONS
Model 520H
Natural Gas Input
(Operating Range) Min.: 13,000 BTU/h
Max.: 199,000 BTU/h
Propane Input
(Operating Range) Min.: 13,000 BTUh
Max.: 199,000 BTU/h
Gas Connection 3/4" NPT
Water Connections 3/4" NPT
Condensate Drain Port
Connection
1/2" NPT
Water Pressure 5 - 150 psi*
Natural Gas Inlet
Pressure Min. 5.0" WC
Max. 10.5" WC
Propane Min. Inlet
Pressure 8.0" WC Max.
14.0" WC
Manifold Pressure of
the 520H Natural: 3.2" WC
Propane: 5.5" WC
Weight 33.1Kg (73 lbs.)
Dimensions
H 651mm (25.6 in.) x W
470mm (18.5 in.) x D 315mm
(12.4 in.)
Ignition Electric Ignition
Electric
Supply 120 VAC / 60 Hz
Consumption
Operating
(520H)
152 W (1.27A)
Standby 8.2 W (0.07A)
Freeze-
Protection
207 W (1.73A)
*40 psi or above is recommended for maximum flow
NOTE
* Check the rating plate to ensure this product matches
your specifications.
* The manufacturer reserves the right to discontinue,
or change at any time, specifications or designs
without notice and without incurring obligations.
INTRODUCTION
This manual provides information necessary for the
installation, operation, and maintenance of the 520H.
The model description is listed on the rating plate which
is attached to the side panel of the water heater.
Please read all installation instructions completely before
installing this product.
If you have any problems or questions regarding this
equipment, consult with the manufacturer or its local
representative.
The 520H is an on-demand, tankless water heaters
designed to efficiently supply endless hot water for your
needs.
The 520H is a high efficiency model with an in-build sec-
ondary heat exchanger that absorbs latent heat from the
exhaust gas.
The principle behind the 520H Water Heater is simple:
Intake port
Primary heat
exchanger
Burner
Cold Water
Inlet
Fan motor
Thermistor
PCB
Hot Water
Outlet
Exhaust
Secondary heat
exchanger
Thermistor
Bypass valve
Water control
valve
Flow sensor
Thermistor
Condensate
drain port
Gas Valve
Gas
Inlet
*This diagram illustrates tankless water heater design con-
cepts only and does not accurately represent to the 520H
physical description.
A hot water tap is turned on.
Water enters the heater.
The water flow sensor detects the water flow.
The computer automatically ignites the burner.
Water circulates through the heat exchanger and then
gets hot.
The computer will modulate the gas supply valve and
water flow to produce the right amount of hot water at the
correct temperature.
When the tap is turned off, the unit shuts down.
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