3
Operating Flow Chart
Standard mode
Recirculation mode
H
o
t W
a
te
r
Co
ld
W
a
te
r
C
o
n
d
e
n
sa
te
G
a
s
Exhaust About 120
℉
(49
℃
)
Water is heated
using the exhaust
gas which is about
400
℉
(200
℃
).
Air & Gas
Mixing
Combusion gas about
400
℉ (200℃)
Primary heat
exchanger
Secondary heat
exchanger
Burner
H
o
t W
a
te
r
R
ec
ir
cu
la
tio
n
L
in
e
C
on
de
n
sa
te
G
a
s
Exhaust About 120
℉
(49
℃
)
Water is heated
using the exhaust
gas which is about
400
℉
(200
℃)
.
Air & Gas
Mixing
Combusion gas about
400
℉ (200℃)
Primary heat
exchanger
Secondary heat
exchanger
Burner
C
o
n
d
e
n
sa
te
G
a
s
Exhaust About 120
℉
(49
℃
)
Air & Gas
Mixing
Combusion gas about
400
℉ (200℃)
Primary heat
exchanger
Secondary heat
exchanger
Burner
Recirculation Line
Water is heated
using the exhaust
gas which is about
400
℉
(200
℃)
.
This water heater is a highly efficient, fully condensing appliance. Unlike
a traditional tankless water heater, a condensing type captures heat
from the exhaust gas and uses it to preheat the incoming cold water as it
passes through the secondary heat exchanger as illustrated below.
The recirculation pipe must
be installed in the field in
order to apply the ‘External
Recirculation Mode’.
This mode allows the
water heater recirculation
pipes to be warmed up
and serving as the freeze
protection function.
This mode is
available without a
recirculation pipe
installed. The water
heater is preheated
and protected from
freezing.
External Recirculation mode
Internal Recirculation mode
Operating Flow Chart
The condensing tankless gas water heater discharges condensate.
When heat from the exhaust gas
is collected within the secondary
heat exchanger, condensation
occurs from moisture in the
exhaust gas and the resulting
water is discharged from the drain
pipe (approx. 2 gallons/hour (7.5
liters/hour) maximum). It is not a
water leak. Do not plug or block
the drain line as it must always be
allowed to freely flow.
Note : The condensate discharged
is acidic with a pH level of
approximately 2-3. A condensate
neutralizer may be required by
local code prior to disposal.
C
o
n
de
n
sa
te
P
ipe
Condensate
comes out from
here.
Chapter 1. – Product Overview
