Install Instructions

6
III. Steam Piping and Trim
A. Design and install boiler and system piping to prevent
oxygen contamination of boiler water.
Oxygen contamination sources are system leaks
requiringadditionofmakeupwater,ttings,and
oxygen permeable materials in distribution system.
Eliminate oxygen contamination sources by repairing
systemleaks,repairingttings,andusingnonpermeable
materials in distribution system.
B. Connect system supply and return piping to boiler.
Refer to Figure 4 for IN3PVNI or Figure 5 for
IN4PVNI, IN5PVNI and IN6PVNI. Also consult
Residential Hydronic Heating Installation and Design
I=B=R Guide. Maintain minimum ½ inch clearance
from combustible materials.
C. Install Safety Valve in Tapping "E". See Figure 3. Use
¾ NPT x 3" nipple and ¾ NPT elbow provided. Safety
Valve must be installed with spindle in vertical position.
WARNING
Installation is not complete unless a safety valve
is installed.
WARNING
Safety valve discharge piping must be piped near
oor to eliminate potential of severe burns. DO
NOT pipe in any area where freezing could occur.
DO NOT install any shut-off valves.
D. Install Drain Valve in Tapping "D". See Figure 3. Use 2
NPT x ¾ NPT bushing provided.
E. Alliance SL™ Indirect Water Heater (if used). Refer
to Alliance SL™ Installation, Operating and Service
Instructions for additional information.
1. Supply and Return Piping. Connect supply piping to
Tapping "N" and return piping to Tapping "M". See
Figure 2. Install zone circulator and strainer in
supply piping. Install check valve to prevent gravity
circulation of boiler water.
2. Limit. Install temperature limit control (Honeywell
L4006A or equal) in Tapping "P". See Figure 3. Set
at 180°F to prevent steam production during
non-space heating periods.
F. Boiler, when used in connection with refrigeration
system, must be installed so chilled medium is piped in
parallel with boiler with appropriate valves to prevent
chilled medium from entering boiler.
G. 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owcontrolvalvesorotherautomatic
means to prevent gravity circulation of boiler water
during cooling cycle.
NOTICE
Before using copper for steam piping, consider the following characteristics of copper piping:
1) high coefcient of thermal expansion can induce mechanical stresses and cause expansion/
contraction noises if not accounted for in the piping system design and installation,
2) high heat transfer rate (heat loss) of uninsulated copper piping must be included in the normal
piping and pickup factors used to size the boiler,
3) soldering or brazing pastes and uxes that end up in the system can cause poor heat transfer,
surging, an unsteady water line and wet steam if not thoroughly removed during the boil out
procedure and,
4) galvanic corrosion of the adjoining metal may occur due to dissimilar metals in certain water
chemistries if dielectric unions are not used.
WARNING
Failure to properly pipe boiler may result in improper operation and damage to boiler or structure.
Do not use softened water in steam boilers. Accelerated boiler corrosion will result. Tie in fresh water
supply to the boiler upstream of a water softener.
Oxygen contamination of boiler water will cause corrosion of iron and steel boiler components, and can
lead to boiler failure. U.S. Boiler Company’s Standard Warranty does not cover problems caused by
oxygen contamination of boiler water or scale (lime) build-up caused by frequent addition of water.