Install Instructions

7 Hydronic piping
Near boiler piping components
1. Boiler system piping:
Boiler system piping MUST be sized per the pipe
requirements listed in Table 6B. Reducing the pipe size
can restrict the  ow rate through the boiler, causing
inadvertent high limit shutdowns and poor system
performance. Flow rates are based on 20 feet (6 m) of
piping, 4 - 90° elbows, and 2 - fully ported ball valves.
2. Boiler system circulating pump:
Field supplied.  e boiler circulating pump should be
based on the heat exchanger pressure drop and any
additional piping.
3. Domestic hot water circulating pump:
Field supplied.  e pump MUST be sized to meet
the speci ed minimum  ow requirements listed in FIG.
7-3. Consult the indirect water heater operating guide to
determine  ow characteristics for the selected product
used.
4. Variable speed boiler system circulator:
Knight XL boilers are capable of controlling a variable
speed boiler system circulator. Variable speed circulators
MUST be sized to meet the speci ed minimum  ow
requirements listed in FIG. 7-3 at full speed.
5. Boiler isolation valves:
Field supplied. Full port ball valves are required. Failure
to use full port ball valves could result in a restricted  ow
rate through the boiler.
6. Check valves:
Field supplied. Check valves are recommended for
installation as shown in FIG.’s 6-7 through 6-11. Failure
to install check valves could result in a reverse  ow
condition during pump(s) o cycle.
7. Domestic indirect hot water isolation valves:
Field supplied. Full port ball valves are required. Failure
to use full port ball valves could result in a restricted  ow
rate through the boiler.
8. Anti-scald mixing valve:
Field supplied. An anti-scald mixing valve is
recommended when storing domestic hot water above
115°F (46°C).
9. Unions:
Field supplied. Recommended for unit serviceability.
10. Temperature and pressure gauge:
Factory supplied.  e temperature and pressure gauge is
shipped loose. It is the responsibility of the contractor to
install the temperature and pressure gauge on the boiler
water outlet.
11. Pressure relief valve:
Factory supplied.  e pressure relief valve is sized to
ASME speci cations.
12. Boiler purge valve:
Field supplied.  e boiler purge valve is used to
remove entrapped air from the heat exchanger during
start-up.
13. System temperature sensor:
Lochinvar supplies a system temperature sensor.  e
sensor is to be installed in the heating loop downstream
from the boiler hot water piping and heating loop
junction.  e sensor should be located far enough
downstream to sense system diluted water temperature.
14. Water Meter:
Field supplied. A water meter to monitor makeup water is
recommended. Makeup water volume should not exceed
5% of total system per year.
15. Strainer/Filter:
Field supplied. Install a Y-strainer or equivalent multi-
purpose strainer/ lter just before the boiler pump at
the inlet of the heat exchanger.  is item is used to
remove system debris from older hydronic systems and
to protect newer systems.
16. Magnetic Separator:
Field supplied. Install a magnetic separator in the
heating system return line as close as practical to the
boiler per the manufacturer’s instructions.
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Installation & Operation Manual