lp-666 Rev. 003 Rel. 001 Date 2.25.20
21
O. Applications*
*NOTE:
Systems shown are
primary/secondary piping
systems. These recommended
systems have a primary (boiler)
loop, and secondary circuits
for heating. The primary loop
and secondary circuits have
separate circulators. The use
of other near boiler piping
configurations could result in
improper flow rates, leading
to inadvertent boiler high limit
shutdowns and poor system
performance.
NOTE:
In piping applications
utilizing a single zone, it
is recommended that the
installer use flow / check valves
with weighted seats at or
near the appliance to prevent
gravity circulation.
FIGURE NOTES:
1. This drawing is meant to
demonstrate system piping
concept only.
2. A mixing valve is
recommended if the DHW
temperature is set above the
factory setting of 119
o
F.
3. Install a minimum of 12
diameters of straight pipe
upstream of all circulators.
4. Install a minimum of 6
diameters of straight pipe up
and downstream of all closely
spaced tees.
5. Piping shown is Primary/
Secondary.
6. The minimum pipe size for
connecting an HTP indirect
fired water heater is 1”.
7. DO NOT down size the boiler
heating loop connections.
8. System flow (Secondary
Loop) must be greater than the
boiler’s Primary Loop flow.
9. Installations must comply
with all local codes.
10. In Massachusetts, a vacuum
relief valve must be installed
on the cold water line per 248
CMR.
11. See Multiple Boiler Manifold
Piping chart, this manual, when
sizing and installing a multiple
boiler system.
WARNING
!
The piping will not support the weight of the circulators. Refer to the circulator manufacturer’s instructions to properly support the circulator.
Failure to comply with these instructions could result in property damage, severe personal injury, or death.
An ASSE 1017 thermostatic mixing valve is recommended on all indirect water heaters if the hot water temperature leaving the heater is
above 119
o
F. Failure to do so could result in substantial property damage, serious injury, or death.
LP-666-C
12/20/18
FROM SYSTEM
TO SYSTEM
BALL VALVE
TYPICAL
AIR SEPARATOR
PURGE VALVE(TYP)
SYSTEM
CIRCULATOR
BACK FLOW
PREVENTER
PRESSURE
REDUCING
VALVE
EXPANSION
TANK
Y-STRAINER
(RECOMMENDED)
MAKE-UP
WATER
BOILER CIRCULATOR
MAY SUBSTITUTE FOR
LOW LOSS HEADER
4 PIPE DIA. SPACING
MAXIMUM
DHW CIRCULATOR
PRESSURE GAUGE
INDIRECT
TANK
CHECK VALVE
CHECK
VALVE
CHECK VALVE
Figure 11 - Single Boiler Space Heating with Indirect Priority
LP-666-D
12/20/18
FROM SYSTEM
TO SYSTEM
BALL VALVE
TYPICAL
AIR SEPARATOR
PURGE VALVE
SYSTEM CIRCULATOR
BACKFLOW
PREVENTOR
PRESSURE
REDUCING VALVE
EXPANSION
TANK
Y-STRAINER
RECOMMENDED
BOILER CIRCULATOR
BALL
VALVE
MAKE-UP
WATER
SYSTEM SENSOR
DHW CIRCULATOR
MAY SUBSTITUTE FOR
LOW LOSS HEADER
4 PIPE DIA. SPACING MAX
PRESSURE GAUGE
BOILER CIRCULATOR
INDIRECT
TANK
CHECK VALVE
CHECK VALVE
Figure 12 - Cascaded Boilers with Indirect Priority on One
