Circuit breaks on temperature rise. 10) Expansion tanks, air scoops and other components left out for clarity. 11) Observe all applicable plumbing and electrical codes. This diagram is for reference only. The installer or designer is responsible for the proper selection and design of the system. A4. 3-way RTC in Primary/Secondary - Heating and DHW using Indirect Water Heater on Primary Loop; without Outdoor Reset (ELECTRICAL) A1 = Aquastat, Indirect DHW Tank C1 = Mixing Valve Actuating Mo

NOTE: Do not use a push type ratchet screwdriver. 1. Strip 7/16 in. of insulation from the wire end. 2. Wrap the wire at least three-fourths of the distance around the screw as shown. 3. Using a standard, flat-headed screwdriver, tighten the screw until the wire is snugly in contact with the screw and contact plate. 4. Tighten the screw an additional one-half turn. Fig. 4—Typical hookup for L8151A in a single zone system. L1 (HOT) L2 1 2 3 1 2 3 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOA

July 2011R PG 3 OF 4 AOSDG25200 Commercial Gas Boilers SUGGESTED SPECIFICATION The hot water supply boiler(s) shall be an A. O. Smith Genesis® Model GW ___________________ having an input rating of __________________ BTU/hr. and capable of supplying no less than _________________GPH at a 100.F temperature rise when fired with Natural/Propane gas. The boiler shall bear the ASME “H” stamp and shall be National Board registered for 160 PSI working pressure. The boiler shall be test certified at 84%

For assistance or additional information, consult a qualified installer, service agency or the gas supplier. • BWC120 This boiler requires a special venting system. Read these • BWC151 instructions carefully before installing. • BWC150 • BWC225 Manufacturer of Hydronic Heating Products P.O. Box 14818 3633 I. Street Philadelphia, PA 19134 Tel: (215) 535-8900 • Fax: (215) 535-9736 • Table of Contents A. Vent System Design 2 B. Assembly of CPVC/PVC Concentric Venting 14 C. Condensate Trap and Drain

5. Hot Surface Ignition Wiring (S937X). Common Connectors Table 3. Connectors Common to Both Spark-to-Pilot and Hot Surface Ignition Options. Connection/Color Pin Mating Plug Description Flame Sense 1 of 1 3/16 in. female quick- connect Connection to Flame Rod Sensor 1/White 1 of 3 Molex® 43061-0003 NTC 1-1 2 of 3 Sensor Common 3 of 3 NTC 1-2 Sensor 2a/White 1 of 2 Molex® 43061-0002 NTC Temperature Sensor 2 of 2 69-2076—01 8 S9360A, S9361A, S9370A, S9371A INTEGRATED BOILER CONTROLLERS S9360A, S9

These options include: 1) 80/125mm concentric venting may be used to achieve longer vent runs. 2) 80/125mm concentric venting may be used for vertical vent applications. 3) An 80/125mm concentric snorkel kit is now offered. 4) Metal-Fab “Corr/Guard” may now be used for stainless steel vent applications. Refer to the installation manual supplied with the boiler for important warnings and other information not covered in this supplement. VII Venting WARNING FAILURE TO VENT THIS BOILER IN ACCORDANC

Stainless vent manufacturer’s wall thimble part numbers are shown in Table 7.5. Note that concentric vent has a “zero” clearance to combustibles and therefore does not require the use of wall thimbles. TABLE 7.5: PERMISSIBLE STAINLESS STEEL VENT SYSTEMS AND PRINCIPLE VENT COMPONENTS (VENT OPTIONS 2, 5) MANUFACTURER VENT SYSTEM SIZE COMPONENT PART NUMBER HEAT FAB SAF-T VENT EZ SEAL 3 BOILER COLLAR CROWN 230510 3 WALL THIMBLE HEAT FAB 7393, 7393GCS, 5391CI 3 HORIZONTAL TERMINAL CROWN 230511 3 VERT

O. Smith OTHER VF™BOILER FEATURES: • ASME 160# W.P. • ASME PRESSURE RELIEF VALVE 125# • FACTORY MOUNTED FLOW SWITCH • MEETS CSD-1 CODE-–FACTORY STANDARD • BRASS DRAIN VALVE • LOW GAS PRESSURE SWITCH • DIGITAL INLET/OUTLET TEMPERATURE READ OUT • MANUAL RESET HI-LIMIT • ALL BRONZE FACTORY MOUNTED PUMP VF™ BOILER APPROVED OPTIONS: . SEQUENCING PANEL . ALARM BELL . SIDEWALL VENT KITS . VERTICAL AND HORIZONTAL DIRECT VENT KITS . SKID-MOUNTED SYSTEMS . DRY CONTACTS FOR ANY BOILER FAILURE . LOW WATER C

2 ea. 2 ea. 2 ea. 2 ea. 2 ea. 2 ea. 2 ea. 2 ea. 2 ea. 8 BASE REAR INSULATION 1 ea. 720603 720604 720605 720606 720607 720608 720609 720610 720611 720612 9 BASE LEG ASSY. 700110 4 ea. 4 ea. 4 ea. 4 ea. 4 ea. 4 ea. 4 ea. 4 ea. 6 ea. 6 ea. 10 1/4-20 X 1/2" SELF TAPPING SCREW 900100 20 ea. 20 ea. 20 ea. 20 ea. 21 ea. 21 ea. 21 ea. 21 ea. 25 ea. 25 ea. 11 1/2" x 2" SEALING STRIP 900146 3.7 ft 4.2 ft 4.8 ft 5.3 ft 5.9 ft 6.4 ft 7.0 ft 7.5 ft 8.0 ft 8.5 ft 12 ROLLOUT SWITCH G4AM0600240C 960122 1 ea. 1

Fully tested for a maximum working pressure of 150 psi Æffvmwre twsimnc ( L'tïifÎl if Rotin L',v Performance independently certified by The Hydronics Institute r Coil Surface (sq. ft.) Tank Volume (Gal) 40 50 60 75 114 Net Weight (lbs) 168 196 196 224 415 Filled Weight (lbs) 514 623 704 861 1370 Model MT040GBR 29-3/4 MT050GBR 26 36 29-3/4 36-3/4 5-3/8 27-1/2 MT065GBR 22 59-1/4 53-1/8 60 5-3/8 27-1/2 MT080GBR 24 59 52-7/8 59-3/4 5-3/8 27-1/2 MT120GBC 28-1/4 62-1/2 55-3/4 63-1/4 6