38
Installation & Operation Manual
6
Hydronic piping
5. Check
valves:
Field supplied. Check valves are recommended for
installation as shown in FIG.’s 6-5 thru 6-14. Failure to
install check valves could result in a reverse flow
condition during pump(s) off cycle.
6. 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 flow
rate through the boiler.
7. Anti-scald mixing valve:
Field supplied. An anti-scald mixing valve is
recommended when storing domestic hot water above
115°F.
8. Unions:
Field supplied. Recommended for unit serviceability.
9. 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.
10. Pressure relief valve:
Factory supplied. The pressure relief valve is sized to
ASME
specifications.
11. Boiler purge valve:
Factory supplied. The boiler purge valve is used to
remove entrapped air from the heat exchanger during
start-up.
12. 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. Typically the sensor will be
located far enough downstream to sense system diluted
water
temperature.
13. Indirect water heaters:
The Knight Wall Hung Fire Tube
boiler may be piped to an indirect
water heater to heat domestic hot water with the space heat
transfer medium. As depicted on pages 41 through 49
there are two options when utilizing an indirect water
heater.
A. The space heating piping will branch off to flow the
space heat transfer medium through a single wall
heat exchanger coil inside the indirect water heater.
B. The indirect water heater is connected to the system
supply piping. A pump controlled by the Knight
Fire Tube boiler’s control will regulate the flow of
water through the indirect water heater. The indirect
water heater’s temperature will be regulated by the
Knight Wall Hung Fire Tube boiler’s control.
The Knight Wall Hung Fire Tube boiler is pre-configured
to control the operation of the DHW pump with
Domestic Hot Water Prioritization programming. The
DHW programming is designed to control and balance the
space heating demand by switching between DHW and
space
heating.
Lochinvar offers the Squire which is a series of indirect
water heaters. The Squire features a stainless steel vessel
with a single wall stainless steel heat exchanger.
WARNING
The National Standard Plumbing Code, the
National Plumbing Code of Canada and the
Uniform Plumbing Code limit the pressure
of the heat transfer fluid to less than the
minimum working pressure of the potable
water system up to 30 psi maximum. Also,
the heat transfer fluid must be water or
other non-toxic fluid having a toxicity of
Class 1, as listed in Clinical Toxicology of
Commercial Products, 5
th
Edition.
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. Y-Strainer:
Field supplied. Install a Y-strainer or equivalent multi-
purpose strainer just before the boiler pump at the inlet of
the heat exchanger. This item is used to remove system
debris from older hydronic systems and to protect newer
systems.
CAUTION
It is up to the installer to ensure the
minimum system flow is not less than the
minimum boiler flow at any time.
Circulator sizing
The Knight Wall Hung Fire Tube boiler heat exchanger does
have a pressure drop, which must be considered in your system
design. Refer to the graph in FIG. 6-2 for pressure drop through
the Knight Wall Hung Fire Tube boiler heat exchanger.
