11
4 - CONNECTING SUPPLY AND RETURN PIPING
4.5 Supply and Return Requirements
1.
Boiler used in connection with refrigeration system,
install so chilled medium is piped in parallel with boiler
with appropriate valves to prevent chilled medium from
entering boiler. See Figure 4-2 page 12.
2.
Boiler piping system of hot water boiler connected to
heating coils located in air handling units where they
may be exposed to refrigerated air circulation must be
equipped with flow control valves or other automatic
means to prevent gravity circulation of boiler water
during cooling cycle.
3.
Hot water boilers installed above radiation level or
as required by authority having jurisdiction shall
be provided with low water cut-off device (Factory
equipped).
4.
Boiler connected to heating system utilizing multiple
zoned circulators, each circulator must be supplied with
flow control valve to prevent gravity circulation.
5.
Hot water boilers and system must be filled with water
and maintained to minimum pressure of 12 psi.
4.6 Special Conditions
• System piping exposed to freezing conditions: Use
inhibited propylene glycol solutions certified by fluid
manufacturer for use with closed water heating
system. Do not use automotive or ethylene glycol.
• Boiler installed above radiation level (or as required by
authority having jurisdiction). Integral low water cut-
off is provided in boiler.
• Boiler used in connection with refrigeration system.
Install piping in parallel with boiler, with appropriate
valves to prevent chilled medium from entering boiler.
• System piping connected to heating coils located in air
handling unit exposed to refrigerated air circulation.
Install flow control valves or other automatic means
to prevent gravity circulation of boiler water during
cooling cycle.
Do not expose boiler and piping to freezing
temperatures.
Note
WARNING
Asphyxiation hazard! Gradual flueway blockage
resulting from condensate induced corrosion may
block boiler passages, resulting in carbon monoxide
and or flame rollout. Install bypass piping if return
temperature is under 130° F. Failure to follow these
instructions could result in death or serious injury.
!
6.
Bypass piping gives ability to adjust boiler water
temperature to fit system or condition of installation.
This method of piping, however, is not typically
required for baseboard heating systems. Typical
installations where bypass piping is required are as
follows:
A. This method is used to protect boilers from
condensation forming due to low temperature return
water (Below 130° F). Generally noticed in large
converted gravity systems other large water volume
systems, and in-floor heating systems. Figures 4-3
and 4-4 pages 13-14
.
B. These methods are used to protect systems using
radiant panels and material they are encased in
from high temperature supply water from boiler and
protect boiler from condensation.
NOTE#1: When using bypass piping, adjust
valves V1 & V2 until desired system temperature
is obtained.
NOTE#2: Bypass loop must be same size piping
as supply and return piping.
7.
Installation using circulators and zone valves are
shown in
Figures 4-2 through 4-7.
For further piping
information refer to AHRI Installation and Piping
Guide.
8.
Install discharge piping from safety relief valve. See
Warning, Page 9 and Figure 4-1.
PN 240012787 Rev. C [11/15/2020]
