Page 1: Table Of Contents
GB250 SERIES INSTALLATION, OPERATION & MAINTENANCE MANUAL AND REPLACEMENT PARTS LIST Gas-Fired Steam Cast Iron Boilers 175,000 to 400,000 Btuh Input Standing Pilot, Standing Pilot & Vent Damper, Intermittent Pilot, Intermittent Pilot & Vent SECTION 1: INTRODUCTION Code Compliance..2 Venting Requirements ...3...
Page 2: Section 1: Introduction
SECTION 1: INTRODUCTION CODE COMPLIANCE Boiler installations must conform to the requirements of the authority having jurisdiction or, in the absence of such requirements, to the National Fuel Gas Code ANSI Z223.1-latest edition. Where required by the authority having jurisdiction, the installation must also conform to the Standard for Controls and Safety Devices for Automatically Fired Boilers, ANSI/ASME CSD-1.
Page 3: Venting Requirements
At time of removal of existing boiler, the following steps shall be followed with each appliance remaining connected to the common venting system...
Page 4: Water Treatment
SHIPMENT OF BOILER Each boiler is shipped in a single carton. Draft hood is vapors, aerosol shipped in a separate carton on larger models.
Page 5: Section 2: Boiler Installation
WARNING: Never install boiler on combustible flooring without combustible flooring pan or on carpeting as heat damage and/or fire may result. CAUTION: Locate boiler so horizontal connecting flue pipe is as short as possible. Maximize height of vertical flue connector.
Page 6: Step 2: Installing Steam Piping
Supply outlet must run full size from boiler to a header at least 24" above top of boiler. Condensate return piping should be connected to boiler through a "Hartford Loop."...
Page 7: Step 3: Installing Hydronic Components
Install draft hood on boiler. If the draft hood shroud has a hole near the relief opening for installing a spill switch, mount draft hood so the hole faces to the front of the boiler.
Page 8 1/4" per foot upwards towards the chimney or vent termination. DANGER: Only the boiler may be served by the vent damper. Do not attempt to use it to vent an additional appliance. This will cause fire or carbon monoxide poisoning.
Page 9 50% of the areas of the additional flue or vent connectors. When an existing boiler is removed from a common venting system, common venting system is likely to be too large for proper venting of appliances remaining connected to it. At time...
Page 10: Step 5: Installing/Testing Gas Piping
4331 Example: Boiler Model GB250-7 is to be installed. The distance from the existing gas meter installation site is 20 feet. What pipe size must be used? The local utility indicates the heating value of the natural gas being supplied is 1,000 Btu per cubic foot.
Page 11: Step 6: Wiring Boiler
TEST WITH AN OPEN FLAME AS FIRE OR EXPLOSION WILL RESULT. For any pressure testing in excess of 1/2 psi, the boiler and its individual shutoff valve must be isolated from the piping system by disconnecting them and capping the outlet(s).
Page 12 For vent damper-equipped models, connect thermostat to blue leads (see Figure 2.6). NOTE: If any of original wire supplied with boiler must be replaced, use similar wire of 105° C rating. Otherwise, insulation may melt or degrade, exposing bare wire.
Page 13 FIGURE 2.13: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS EQUIPPED WITH INTERMITTENT PILOT, VENT DAMPER & MCDONNELL-MILLER #67 LOW WATER CUT-OFF FIGURE 2.14: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS EQUIPPED WITH STANDING PILOT, VENT DAMPER & MCDONNELL- MILLER #67 LOW WATER CUT-OFF (EXCEPT FOR GB250-8 &...
Page 14 FIGURE 2.15: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS EQUIPPED WITH STANDING PILOT, VENT DAMPER & MCDONNELL- MILLER #67 LOW WATER CUT-OFF (FOR GB250-8 & GB250-9, N.G.) FIGURE 2.16: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS EQUIPPED WITH INTERMITTENT PILOT, VENT DAMPER & 400 SERIES LWCO...
Page 15 FIGURE 2.17: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS EQUIPPED WITH STANDING PILOT, VENT DAMPER & 400 SERIES LWCO (EXCEPT FOR GB-250-8 & 9) FIGURE 2.18: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS EQUIPPED WITH STANDING PILOT, VENT DAMPER & 400 SERIES LWCO (GB250-8 &...
Page 16: Section 3: Start-Up & Operation
SECTION 3: START-UP & OPERATION SEQUENCE OF OPERATION For sequence of operation of the particular boiler being installed, refer to Figures 2.13 through 2.18 in Section 2 of this manual. Spill and rollout switches are mounted on Model GB250-5L, GB250-5H, and GB250-6 boilers.
Page 17 Measure the time in seconds that it takes for the boiler to use 10 cubic feet of gas. Divide 36,000 by the number of seconds (this is the number of cubic feet of gas used per hour).
Page 18 If you do not follow these instructions exactly, a fire or explosion may result with property damage, personal injury, or loss of life. A. BEFORE OPERATING smell all around the appliance area for gas. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.
Page 19: Section 4: Maintenance
4. Provide pipe connection (full size) from pressure relief valve opening to a convenient drain to serve as a vent. 5. Fill the boiler with a manual fill valve until water starts to trickle from this pipe. 6. Fireboiler at sufficient rate to generate and maintain steam.
Page 20: How To Change Orifices
2/3 full). The time required could vary up to 3 hours. 8. Turn burner to off position. While boiler is still hot, drain completely through boiler drain. Make sure that all low points in the return line are also completely drained.
Page 21: Replacement Parts List
MODEL GB250 SERIES REPLACEMENT PARTS LIST ORDERING INFORMATION When ordering replacement parts, provide the model and serial number shown on the unit rating plate as well as the part number and name as shown in the parts list. Parts may be obtained from your local Smith heating contractor.
Page 22 NAME OF PART Section, Rear Section, Intermediate Section, Front (No Coll Opening) Heat Exchanger/Assembled Block Heat Exchanger/Assembled Block Heat Exchanger/Assembled Block Heat Exchanger/Assembled Block Heat Exchanger/Assembled Block Port Seal - 5" Port Seal - 2" Pipe Plug 2" Sq. Hd. Low Water Cut-Off (CG400) Pigtail - 1/4"...
Page 23 NAME OF PART Honeywell Intermittent Pilot System Pilot Ass'y N.G. - Q3451B-1103 Pilot Ass'y N.G. - Q3451B-1103 Pilot Ass'y N.G. - Q3451B-1103 Pilot Ass'y N.G. - Q3451B-1103 Pilot Ass'y N.G. - Q3451B-1103 Pilot Ass'y L.P. - Q3451B-1103 Pilot Ass'y L.P. - Q3451B-1103 Pilot Ass'y L.P.
Page 24 JACKET ASSEMBLY...
Page 25: Warnings
Carbon monoxide (CO) is a gas which is odorless, colorless and tasteless but is very toxic. If your Smith boiler is not working properly, or is not vented properly, dangerous levels of CO may accumulate. CO is lighter than air and thus may travel throughout the building. Brief exposure to high concentrations of CO, or prolonged exposure to lesser amounts of CO, may result in carbon monoxide poisoning.
Page 28: North Elm Street Westfield, Ma
WESTCAST, INC. 260 NORTH ELM STREET WESTFIELD, MA 01085 TEL. (413) 562-9631 FAX (413) 562-3799 www.smithboiler.com...

This manual is also suitable for:

Gb250-s-5l Gb250-s-5h Gb250-s-6 Gb250-s-7 Gb250-s-8 Gb250-s-9

Smith Cast Iron Boilers GB250 SERIES Installation & Operation Manual

Section 1: Introduction

Section 2: Boiler Installation

Section 3: Start-Up & Operation

Section 4: Maintenance

Westcast, Inc.

North Elm Street Westfield, Ma

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