Relief Valve; System Piping - Lochinvar Copper-Fin II CX401 Designer's Manual

Lochinvar
secondary pump(s). When piped correctly,
IMPORTANT:
Operation
the secondary pump helps to prevent flow
of this boiler
through the boiler(s) when they are not firing.
on low
Use of a primary/secondary system will
temperature
eliminate the need for a System or Boiler
systems
Bypass. (Figure 19) depicts one example of
requires special
primary/secondary piping.
piping to insure
correct
operation.
Consult low
temperature
HEATING SUPPLY
LOOP
system section
for piping
details.
(FIG. 19) PRIMARY/SECONDARY SYSTEM PIPING
Water Flow Switch
Due to the low water content (between 1 and 6
gallons) of the Copper Finned Tube heat
exchanger, a flow switch is factory installed as
a low water cutoff device on all models. The
flow switch is installed in the outlet piping of the
boiler and wired into the ignition system. A
minimum of 20 GPM is required to make the
flow switch. Per ASME CSD1 and in most
localities, a flow switch is accepted as a low
water cutoff for boilers requiring forced
circulation. (See CSD1 CW-210) It is prudent to
verify preference with the local code official.
A specially sealed flow switch and conduit are
furnished for outdoor installations.
Low Water Cutoff
If this boiler is installed above radiation level, a
low water cutoff device must be installed at
the time of boiler installation (option, available
from factory).
20
L o c h i n v a r
MAKE-UP WATER
TO FLOOR
DRAIN
*12" MAX
HEATING RETURN LOOP
'
D E S I G N E R S G U I D E

Relief Valve

This boiler is supplied with a pressure relief
valve sized in accordance with ASME Boiler and
Pressure Vessel Code, Section IV "Heating Boilers".
Low Flow Systems
When the system flow rate is less than the
minimum flow required for proper boiler
LIT0476
operation, the boiler should be installed with a
primary/secondary piping system.
This will allow the installation of a secondary-
circulating pump sized specifically to provide a
higher flow rate through the boiler and the
secondary loop piping to ensure proper
operation. See "Primary/Secondary Piping"
for installation and piping requirements.
High Flow Systems
When the flow rate of the system exceeds the
maximum allowable flow rate through the
boiler (Table L), boiler bypass piping should be
installed. The bypass will divert the required
portion of the system flow to the boiler and
bypass excess system flow. This will effectively
reduce boiler flow to an acceptable rate and
increase system flow. The bypass piping should
be sized equal to the system piping. Figure 18
depicts the proper piping arrangement for the
boiler bypass.
MAKE-UP WATER
HEATING SUPPLY
LOOP
(FIG. 20) HIGH FLOW SYSTEM PIPING
LIT0471
TO FLOOR
DRAIN
HEATING RETURN LOOP