Boiler Piping
Additional Limit Control
If a separate LWCO device is required by cer-
tain local jurisdictions or when the boiler is
installed above the system piping, the follow-
ing guidelines must be followed:
- The LWCO device must be designed
for water installations, electrode probe-
type is recommended.
- The LWCO device must be installed in
a tee connection on the boiler supply
piping above the boiler.
- Wiring of the LWCO device to the PRES-
TIGE Excellence is done directly onto the
low voltage terminal strip, reference Fig.
19 page 29 for available terminals for an
external limit (manual or auto reset).
If the installation is to comply with ASME or
Canadian requirements, an additional high
temperature limit may be needed. Consult
local code requirements to determine compli-
ance. The limit should be installed as follows:
- Install the limit in the boiler supply pip-
ing between the boiler and any isolation
valve.
- Consult heat exchanger for maximum
set point of limit.
- For wiring of the limit reference Fig. 19,
page 29, using the external limit/manual
reset terminals on the low voltage termi-
nal strip. This will provide a "hard" lock-
out requiring a manual reset of the control.
Backflow Preventer
- Use a backflow preventer valve in the
make-up water supply to the unit as
required by local codes.
Boiler System Piping Applications
It is recommended on all piping applica-
tions to utilize a primary/secondary pip-
ing arrangement as a means to provide
freeze protection of the boiler, which is
an integral function of the boiler control.
Maintain the minimum boiler flow rate,
see Graph 2 on page 81. For other pip-
ing arrangements, contact ACV-Triangle
Tube Technical Support or consult other
approved/recognized design arrange-
ments.
On piping applications utilizing a single
zone or other recognized piping design
arrangements, it is recommended that the
installer uses flow/check valves with
weighted seats at or near the appliance to
prevent gravity circulation.
Expansion Tank and Makeup Water
Ensure the expansion tank is properly sized for
the boiler volume (5 gallons [19 L]) and the
system volume and temperature.
Undersized expansion tanks will cause
system water to be lost through the pres-
sure relief valve and cause additional
makeup water to be added to the system.
Eventual boiler heat exchanger failure
can result due to this excessive makeup
water addition.
The expansion tank must be located as shown
in Figs. 9 through 12 on pages 20 and 21 or as
per recognized design methods. Refer to the
expansion tank manufacturer instructions for
additional installation details.
CAUTION
BEST PRACTICE
BEST PRACTICE
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