14
INSTALLATION
Piping Configuration
When employing a Tankless Water Heater in a hydronic
system, the system is considered an Open Loop System
when configured to simultaneously deliver both domestic
hot water and space heating. By definition, if the circuit
is sealed off from the atmosphere at all locations (as is true
for most modern hydronic systems) it is called a closed
loop system. If the circuit is open to the atmosphere at
any point, it is called an open loop system. Current
tankless products are not certified for closed loop
applications.
Open Loop System
If piping is done in accordance with the recommended
schematic diagram shown in Figure 11, the following purge
and priming procedure applies.
P U R G I N G A N D
P R I M I N G T H E S Y S T E M
The following procedure describes how the RedZone
TM
system may be piped to eliminate the need for a “purge
cart” to fill the system and remove entrapped air bubbles.
STEP 1:
CLOSE ball valve 3 (BV3).
STEP 2:
OPEN drain valve 3 (DV3) to which a hose
MUST be connected and draining to a sink,
drain or outdoors.
STEP 3:
CLOSE drain valves 1 and 2 (DV1 and DV2) and
OPEN ball valve 2 (BV2).
STEP 4:
OPEN cold water supply main valve
(ball valve 1 - BV1). The system will begin the
prime/purge process using the street pressure.
Entrapped air bubbles being pushed out of
the system will be evident by a slight vibration
of the discharge hose connected to drain valve
3 (DV3). The hose will stop vibrating when
laminar flow is achieved.
STEP 5:
CLOSE drain valve 3 (DV3).
STEP 6:
OPEN ball valve 3 (BV3). The system is now
purged, primed and ready to go.
NOTE:
For an open loop system, use expansion tank and mixing
valve approved for potable water use only.
Field Supplied
A Coil and Ducting
Field Supplied
Refrigerant Lines to
Condensing Unit
Hydronic Air Handler
Blower Assemby
Pump with Removable
Check Valve
REDZONE
Air Handler
Hydronic
Heating Coil
(Optional)
(Optional)
Air Separator
Control Box
Thermostat
Anti-Scald
Mixing Valve
Domestic
Hot Water
Tankless
Water
Heater
Gas Supply
Cold Water
Supply
Optional
Check Valve
(If Required by Local
Municipality)
Expansion
Tank
F I G U R E 11
Typical Piping Arrangement For Direct Space Heating
and Domestic Water Supply with Tankless
R E D Z O N E
T M
D V S S E R I E S A I R H A N D L E R M A N U A L
WARRANTY NOTICE
Expansion Tank and Thermostatic Mixing Valve must be
installed with every open loop installation or warranty
on product becomes null and void.
