General Piping Requirements; Heating System Piping - RBI 8900 Series Installation & Operation Manual

Page 10 SERIES 8800 & 8900 INSTALLATION AND OPERATING INSTRUCTIONS

GENERAL PIPING REQUIREMENTS

CAUTION: Improper piping of this boiler/water heater
will void the manufacturer's warranty and can cause
boiler failure resulting in flooding and extensive
property damage! Excessive water hardness causing
lime build-up in the copper heat exchanger tubes is
NOT covered under the manufacturer's warranty.
Excessive pitting and erosion of the internal surface
of the copper heat exchanger tubes is NOT covered
under the manufacturer's warranty if the result
of high water fl ow rates, see Table 6A and 6B. Return
water temperatures below 110°F, 43°C will result
i n h e a t ex c h a n g e r d a m a g e f ro m ex c e s s i v e
condensation voiding the manufacturer's warranty,
see Primary/Secondary Piping Figure 7.
NOTE: Shut off valves and unions should be
installed at the inlet and outlet connections of the
boiler/hot water heater to provide for isolation of the
unit should servicing be necessary.
Relief Valve
Pipe the discharge of the pressure relief valve to prevent
scalding in the event of a discharge, see Figure 6. The
discharge piping must be sized the same as the
pressure relief valve outlet and installed to allow
complete drainage of both the relief valve and the
discharge piping.
Figure 6
OUTLET
INLET
RIOM-46
WARNING: Never install any type of valve
between the boiler/water heater and the relief
valve or an explosion causing extensive
property damage, severe personal injury or
death may occur!
Flow Switch
The fl ow switch supplied with the boiler/water heater
must be wired to the terminal strip in the junction box
to prevent the boiler from fi ring unless there's adequate
water fl ow through the unit. The fl ow switch must be
installed in the supply piping adjacent to the boiler outlet
connection.
1" (25mm) CLEARANCE MUST
BE MAINTAINED BETWEEN HOT
WATER PIPING AND COMBUSTIBL E
CONSTRUCTION .
DISCHARGE PIPE SIZE TO
EQUAL VALVE OUTLET .
DO NOT RESTRICT FLOW.
DISCHARGE SO AS TO AVOID
EXPOSURE OF PERSONS TO
HOT LIQUID OR VAPOR AND
ALLOW COMPLETE DRAINAGE
0F RELIEF VALVE AND PIPING.
CAUTION: Failure to properly install the fl ow switch
may result in damage to the boiler/water heater heat
exchanger voiding the warranty!

HEATING SYSTEM PIPING

General Piping Requirements
All heating system piping must be installed by a qualifi ed
technician in accordance with the latest revision of the
ANSI/ASME Boiler and Pressure Vessel Code, Section
IV, and ANSI/ASME CSD-1, Standard for Controls and
Safety Devices for Automatically Fired Boilers. All
applicable local codes and ordinances must also be
followed. A minimum clearance of 1 in, 25 mm must be
maintained between heating system pipes and all
combustible construction. All heating system piping must
be supported by suitable hangers not the boiler.
The thermal expansion of the system must be
considered when supporting the system. A minimum
system pressure of 12 psig, 82.7 kPa must be
maintained.
Heating Boiler Piping Connections
The supply and return connections should be sized to
suit the system, see Table 5.
Table 5 - Supply & Return Pipe Sizing
Model Supply
1
8900 2 / " NPT
2
8800 3" Victaulic
*Models 420-950 may have 2
installed.
Pump Requirements
This low mass boiler requires a continuous minimum
water fl ow for proper operation. The system pump must
be sized to overcome the head loss of the boiler and
the heating system in order to achieve the required
temperature rise. Table 6A and 6B provides the heat
exchanger pressure drop and temperature rise fi gures.
The temperature rise across the boiler must never
exceed 35°F, 19.4°C. The pump delay turns the pump
on each time the burners fi re and runs the pump for up
to 10 minutes after the call for heat is satisfi ed.
CAUTION: A temperature rise outside of the range
listed in Table 6A and 6B indicates that the fl ow rate
through the heat exchanger is incorrect which will
damage the heat exchanger voiding the warranty!
The maximum allowable fl ow rate through an 8900
boiler with copper heat exchanger is 92 GPM,
5.8 L/s and 185 GPM, 11.7 L/s on single pass.
The maximum allowable fl ow rate through an 8800
boiler with copper heat exchanger is 185 GPM,
11.7 L/s and 370 GPM, 23.3 L/s on single pass.
Return
1
2 / " NPT
2
3" Victaulic
1
/ " x 2" reducing fi tting
2