Ke y – American Water Heater Tankless Water Heater System User Manual
Page 23
23
Domestic Hot Water - Circulation Systems
3 Tankless Water Heaters with Gas or Electric Tank
Preferred Piping Installation
Tankless
Water Heater
Tankless
Water Heater
Drawing Number:
Drawing Date:
Pres
s
ure R
e
lief
Valv
e
3/
4"
Ball
Valv
e
3/
4"
U
n
ion
C
h
ec
k Valv
e
Ke
y
S
Pres
s
ure R
egulat
or
C
irc
ulat
ing Pum
p
Solenoid Valv
e
Boiler D
rain Valv
e
WH-3-RGE
February 27, 2008
This is not an engineering drawing; it is intended only as a guide and not
as a replacement for professional engineering project drawings.
This
drawing is not intended to describe a complete system. It is up to the
contractor or engineer to determine the necessary components and
configuration of the particular system to be installed.
The drawing does
not imply compliance with local building code requirements. It is the
responsibility of the engineer or contractor to ensure that the installation is
in accordance with all local building codes. Confer with local building
of
ficials before installation.
Gas Supply
Tankless
Water Heater
Primary
Su
b 1
C
o
ld
W
a
te
r
S
u
p
p
ly
L
in
e
Hot
Water Supply Line
Smaller Return Line
Can Be Used After
The Last Fixture
Expansion Tank
Su
b 2
(Optional) Header Sized One Pipe
Size Larger Than Hot
Water Supply Line - (
To e
liminate c
old
water
sa
ndwic
h effec
t
cau
s
ed b
y
frequ
ent
On/Off op
eration)
Gas or Electric
Tank Water
Heater
Tank Water Heater sized to
maintain circulation loop
temperature
Building Outlets
For this application:
Pump should be controlled by an
Aquastat,
T
imer or Combination
Aquastat and
T
imer
.
Pump to be sized to maintain circulation
loop temperature.
The pump should be sized to overcome the
pressure loss through the tank water heater
,
and supply and return plumbing in the
circulation loop. Reference the section
Pump Sizing for Circulation
.
Pump to be of bronze or stainless construc-
tion.
A
quastat C
onnec
tion
Tankless
Equipment List
QTY
Tankless 3
W
a
ter Heaters
Electronic Connection *
* Refer to Tankless Accessories
and Model
Applicability for
electronic connection details.