6
Hydronic piping
(continued)
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 fl ow rate through the boiler, causing
inadvertent high limit shutdowns and poor system
performance. Flow rates are based on a full fl ow
application.
2. Boiler system circulating pump:
Field supplied. The boiler circulating pump should be
based on system requirements.
3. Domestic hot water circulating pump:
Field supplied. The pump MUST be sized to meet
the
specifi ed minimum fl ow requirements listed in
FIG. 6-4. Consult the indirect water heater operating
guide to determine fl ow characteristics for the selected
product
used.
4. Variable speed boiler circulator:
FTXL boilers are capable of controlling a variable speed
boiler circulator. Variable speed circulators MUST
be sized to meet the specifi ed minimum fl ow requirements
listed in FIG. 6-4 on page 41 at full speed. To be used
in primary/secondary systems only.
5. Boiler
isolation
valves:
Field supplied. Full port ball valves are required. Failure
to use full port ball valves could result in a restricted fl ow
rate through the boiler.
6. Check
valves:
Field supplied. Check valves are recommended for
installation as shown in FIG.’s 6-5 through 6-10. Failure
to install check valves could result in a reverse fl ow
condition during pump(s) off 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 fl 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. The 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. The pressure relief valve is sized to
ASME
specifi cations.
39
Installation & Operation Manual
Circulator sizing
The FTXL heat exchanger does have a pressure drop, which
must be considered in your system design. Refer to the
graphs in FIG. 6-4 for pressure drop through the FTXL heat
exchanger.
12. Boiler purge valve:
Field supplied. The 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. The
sensor is to be installed in the heating loop downstream
from the boiler hot water piping and heating loop
junction. The sensor should be located far enough
downstream to sense system diluted water temperature.
14. Y-Strainer:
Field supplied. A Y-strainer or equivalent multipurpose
strainer is recommended at the inlet of the heat exchanger
to remove system particles from older hydronic systems
and protect newer systems.
15. Motorized isolation valve (optional):
Field supplied. A motorized isolation valve can be used
to isolate the boiler from the system piping.
