Install Instructions
29
4 Water connections
Inlet and outlet connections
For ease of service, install unions on the water inlet and water
outlet of the unit. The connection to the unit marked “Inlet”
on the header should be used for return from the system. The
connection on the header marked “Outlet” is to be connected to
the supply side of the system.
NEED NEW IMAGE
Figure 4-1_Water Connections_Models 497 - 797
2" NPT
WATER
INLET
INSPECTION
PLUGS
2" NPT
WATER
OUTLET
Relief valve
This unit is supplied with a relief valve(s) sized in accordance
with ASME Boiler and Pressure Vessel Code, Section IV
(“Heating Boilers”). The relief valve(s) is installed in the vertical
position and mounted in the hot water outlet. No valve is to be
placed between the relief valve and the unit. To prevent water
damage, the discharge from the relief valve shall be piped to a
suitable floor drain for disposal when relief occurs. No reducing
couplings or other restrictions shall be installed in the discharge
line. The discharge line shall allow complete drainage of the
valve and line. Relief valves should be manually operated at
least once a year.
⚠ CAUTION
Avoid contact with hot discharge water.
Water flow switch
A water flow switch is factory installed in the outlet piping on
all heating boilers and water heaters. The flow switch must
prove water flow before a trial for ignition can begin. The flow
switch requires a minimum flow of 15 - 18 GPM on Models
497 - 747 and 26 GPM on Models 987 - 2067 to make the flow
switch and start burner operation. A water flow switch meets
most code requirements for a low water cutoff device on boilers
requiring forced circulation for operation.
Low water cutoff (if equipped)
If this boiler is installed above radiation level, a low water
cutoff device must be installed at the time of boiler installation.
An electronic low water cutoff is available as a factory supplied
option on all models. The low water cutoff should be inspected
every 6 months.
Heating boiler installations
Piping of the boiler system
The drawings in this section show typical boiler piping
installations, see FIG.’s 4-5 through 4-8. Before beginning
the installation, consult local codes for specific plumbing
requirements. The installation should provide unions and
valves at the inlet and outlet of the boiler so it can be isolated
for service. An air separation device must be supplied in the
installation piping to eliminate trapped air in the system.
Locate a system air vent at the highest point in the system.
The system must also have a properly sized expansion tank
installed. Typically, an air charged diaphragm-type expansion
tank is used. The expansion tank must be installed close to the
boiler and on the suction side of the system pump to ensure
proper operation. A water meter to monitor makeup water is
recommended. Makeup water volume should not exceed 5%
of total system per yearInstall 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
The boiler system should not be operated
at less than 12 PSIG(83 kPa) (Non-metallic
system piping must have an oxygen barrier
to be considered a closed loop).
Hot water piping must be supported by suitable hangers or floor
stands, NOT by the boiler. Copper pipe systems will be subject
to considerable expansion and contraction. Rigid pipe hangers
could allow the pipe to slide in the hanger resulting in noise
transmitted into the system. Padding is recommended on rigid
hangers installed with a copper system. The boiler pressure
relief valve must be piped to a suitable floor drain. See the Relief
Valve section on this page.
⚠ CAUTION
A leak in a boiler “system” will cause the
“system” to intake fresh water constantly,
which will cause the tubes to accumulate a
lime/scale build up. This will cause a non-
warrantable failure.
Installation & Service Manual
Figure 4-2_Water Connections_Models 987 - 2067
2-1/2" NPT
WATER
INLET
INSPECTION
PLUGS
2-1/2" NPT
WATER
OUTLET