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SHORT TRIM Versatile Multi-Venting Configurations n Two-pipe direct-venting vertical and /or horizontal sidewall, with all combustion makeup air drawn from outside the building 70 Equivalent Feet Exhaust 70 Equivalent Feet Intake 90 Degree Elbows = 10 Feet 45 Degree Elbows = 5 Feet Boot Tee = 5 Feet n Standard-venting, vertical or horizontal sidewall 100 Equivalent Feet Max 90 Degree Elbows = 10 Feet 45 Degree Elbows = 5 Feet Boot Tee = 5 Feet DIRECT-VENTING SIDEWALL CONVENTIONAL VENTING VENTING

60-2553—3 2 L8151A INSTALLATION L8151A INSTALLATION CAUTION • Disconnect power supply before beginning installation to prevent electrical shock or equipment damage. • Avoid making sharp bends or kinks in the capillary. Bends should be no less than 1 in. (25 mm). IMPORTANT: Terminals on these Aquastat® Relays are approved for copper wire only. Fig. 1—Approximate L8151 dimensions in in. (mm). 1/8 (3) 1-1/4 (32) 1-1/4 (32) 13/16 (21) 2-3/6 (56) 3-5/16 (84) 4-23/32 (120) 4-5/16 (110) KNOCKOUT FOR 1/

Repair or replace any parts that are worn, damaged, or failing to make a good connection. AOS WPC - Tech Training 42 of 72 Ashland City, TN © 2007 Servicing should only be performed by a Qualified Service Agent VF BOILER SERVICE MANUAL ERROR MESSAGES (CONT) DISPLAYED MESSAGE CONDITION/INDICATES CHECK/REPAIR “Display Fail” • Plug UIM comm cable into the other “internal” comm port on the MCB. (see page 32) Communication between the MCB and UIM has • Check comm cable to the UIM. Turn off power been

Gasket, Port (1/8" Thick)...................... 191576 33 13 .... Nut, Hex 1/4", Serrated......................... 210226 34 14 .... Manifold Assembly - Air/Gas................ 192309 35 15 .... Nipple, Close 1/8"................................ 191147-3 36 16.... Nipple, Close Stainless........................191772-1 37 17 .... Nipple, Tapped......................................86505-3 38 18 .... Nipple, 1-1/4" x 38 1/2"........................86505-28 40 19 .... Nipple, 1-1/4" x 28 3/

Figure 5 Main burner flame, typical Transparentblue flame Inner flame 26024 . Monthly ..................... Main burner flames 1. See Figure 4. Remove burner input plenum cover plate “A”. 2. Visually inspect burner flames: • Proper main burner flame (see Figure 5): a. Yellow-orange streaks may appear (caused by dust). • Improper main burner flame: a. Overfired — Large flames. b. Underfired — Small flames. c. Lack of primary air — Yellow tipping on flames (sooting will occur). . Periodically.....

The burner serves as the common grounding area. If there is not a good metal-to-metal contact between the burner and ground, run a lead from the burner to ground. NOTE: “Earth” ground is not required. S937XA Hot Surface Ignition Versions These models provide operating control of a direct ignition system using a hot surface igniter. Additional components required to complete the system must be ordered separately. They include: • Dual Valve Combination Gas Control: Any direct ignition gas control

3. A common ground is required for the S93XX and the main burner. The 24V “secondary” plug internally grounds one side of the transformer. Any auxiliary controls or limits must not be in the grounded leg. In addition, the appliance should be earth-grounded. 4. Make sure the transformer has adequate VA. The ignition module requires at least 0.2A at 24 Vac. Add the current draws of all other devices in the control circuit, including the gas control, and multiply by 24 to determine the total VA req

Where the appliance may be installed in a humid atmosphere, make sure air circulation around the module and gas control is adequate to prevent condensation. It is also important to regularly check out the system. A NEMA 4 enclosure may be needed. Corrosive Chemicals Corrosive chemicals can also attack the module and gas control and eventually cause a failure. Where chemicals may be used routinely for cleaning, make sure the cleaning solution cannot reach the controls. Where chemicals are likely

Operating Ambient Temperature: -30°F to +150°F. Shipping Ambient Temperature: -40°F to +175°F. Flame Monitoring (May vary by model): Flame Establishing Period (FEP): Maximum 2 seconds. Flame Failure Response Time (FFRT): Maximum: 2 seconds @ 1 .A. Flame Stabilization Time: 4 seconds. Time from ignit ing the main burner and detecting loss of flame (the flame current is allowed to be under the flame lost threshold for this time while waiting for burner to stabilize). Flame Lost Threshold: 0.23 .A.