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VIII System Piping

A. General System Piping Precautions

CAUTION
THE HEAT EXCHANGER USED IN THE BWC IS MADE FROM A SPECIAL ALUMINUM ALLOY.
FAILURE TO TAKE THE FOLLOWING PRECAUTIONS COULD RESULT IN SEVERE BOILER
DAMAGE.
• INSTALL BOILER SO THAT THE GAS IGNITION SYSTEM COMPONENTS ARE PROTECTED
FROM WATER (DRIPPING, SPRAYING, RAIN, ETC) DURING APPLIANCE OPERATION AND
SERVICE (CIRCULATOR REPLACEMENT, ETC).
• OPERATION OF THIS BOILER IN A SYSTEM CONTAINING SIGNIFICANT AMOUNTS OF
DISSOLVED OXYGEN CAN CAUSE SEVERE HEAT EXCHANGER CORROSION DAMAGE.
• USE ONLY ANTIFREEZE SPECIFICALLY PERMITTED ON PAGE 37 OF THIS MANUAL.
• MAKE SURE THAT THE WATER USED TO FILL THE SYSTEM MEETS THE REQUIREMENTS
OUTLINED IN THE START-UP AND CHECKOUT SECTION OF THIS MANUAL (PAGE 37).
• NEVER USE PETROLEUM BASED CLEANING OR SEALING COMPOUNDS IN THE BOILER
SYSTEM. THESE PRODUCTS COULD DAMAGE ELASTOMER SEALS AND GASKETS IN THE
SYSTEM AND COULD RESULT IN PROPERTY DAMAGE.
• THIS BOILER IS NOT DESIGNED FOR USE IN SYSTEMS CONTAINING SIGNIFICANT
AMOUNTS OF MAKEUP WATER. REGULAR ADDITIONS OF MAKEUP WATER MAY CAUSE
SEVERE HEAT EXCHANGER DAMAGE.
• BEFORE CONNECTING BOILER, MAKE SURE THAT THE SYSTEM IS FREE OF SEDIMENT,
FLUX AND ANY RESIDUAL BOILER WATER ADDITIVES. FLUSH THE SYSTEM IF NECESSARY
TO ENSURE THAT THESE CONTAMINATES ARE REMOVED.
• MAINTAIN THE PRESSURE IN THE BOILER AT A MINIMUM OF 12 PSI.
• DESIGN SYSTEM TO ENSURE THAT THE FLOW FALLS WITHIN THE LIMITS CALLED FOR IN
TABLE 8.1.

B. System Design

Proper operation of the BWC boiler requires that the water flow through the boiler remain within the limits shown in
Table 8.1 any time the burner is firing. Failure to maintain the flow within these limits could result in erratic operation
or premature boiler failure. There are three basic methods that can be used to pipe the BWC boiler. The instructions on
the following pages describe three alternative methods for piping BWC boilers and explain how to size the circulator
and piping for each one. Additional information on hydronic system design may be found in Installation of Residential
Hydronic Systems (Pub. #200) published by the Hydronics Institute in Berkeley Heights, NJ.

TABLE 8.1: FLOW REQUIREMENTS THROUGH BOILER

BOILER MODEL MIN. REQUIRED FLOW
(GPM)
MAX. ALLOWABLE
FLOW (GPM)
BWC150 8 15
BWC225 9 23