Honeywell S8910U Universal Hot Surface Ignition Module

Application

The SUPER TRADELINE(R) S8910U Universal Hot Surface Ignition Module is designed to provide easy field replacement of a wide range of hot surface ignition modules manufactured by Honeywell, Robertshaw, and White-Rodgers. The S8910U Module provides operating control of a direct ignition system using a 120 Vac hot surface igniter.

Features

• Replaces many White-Rodgers, Robertshaw, and Honeywell hot surface ignition models (See Tables 2, 3, and 4).
• For 120 Vac (up to 5.0A) surface igniter (Norton 201/271 or equivalent).
• For local (single rod) or remote (dual rod) rectification type flame sensing.
• Includes easy-to-use instructions and accessories for adapting to existing modules.
• Provides one or three ignition trials (four-second or seven-second trials) per call for heat; prepurge of 32 seconds or less; up to 96 seconds between purge trial times.
• Operating temperature range: -40°F to 175°F (-40°C to 79°C).

Product Data

Electrical Ratings

• Control Voltage: 24V, 60 Hz.
• Maximum Valve Contact Rating: 2A.
• Current Draw: 0.4A plus valve load.
• Hot Surface Igniter Voltage: 120 Vac, 60 Hz.
• Igniter Contact Rating: 5A at 120 Vac.

Ambient Operating Temperature

-40°F to +175°F (-40°C to +79°C).

Specifications

IMPORTANT: Specifications do not include normal manufacturing tolerances. Performance may vary slightly under different conditions.

Super TRADELINE(R) Models

The SUPER TRADELINE(R) S8910U package includes the S8910U control, instructions, and accessories for adapting to existing hot surface ignition modules. Accessories include a White-Rodgers adapter, Robertshaw ground lead, quick-connects, selection tabs, and wire labels.

NOTE: The S8910U is intended for direct replacement of defective ignition controls. Ensure the appliance and control system operate safely and reliably before replacement.

WARNING: EXPLOSION HAZARD. CAN CAUSE INJURY OR EQUIPMENT DAMAGE. Use only for direct replacement. Consult Tables 2-4 before replacing an existing module. Using an unlisted module or incorrect selection tab can cause appliance malfunction.

IMPORTANT: The S8910U is designed for 60 Hz systems only.

Hot Surface Igniter Requirements

Norton Model 201 or 271 or equivalent. If using a different igniter, it must meet minimum specifications including reaching 1832°F (1000°C) within 34 seconds with 102 Vac, maintaining 500M ohm insulation resistance, and not developing insulating layers that prevent flame sensing. Igniter surface area immersed in flame should not exceed one-fourth of the grounded area. Igniter current draw at 132 Vac must not exceed 5A.

Ordering Information

Refer to the TRADELINE(R) Catalog or price sheets for ordering numbers. Specify order number, desired accessories, and any additional system components separately.

For questions or comments, contact your local Home and Building Control Sales Office or write/phone: Home and Building Control Customer Logistics, Honeywell Inc., 1885 Douglas Drive North, Minneapolis, Minnesota 55422-4386.

International offices and manufacturing locations are also listed.

Installation

WARNING: FIRE OR EXPLOSION HAZARD. FOLLOW ALL SAFETY WARNINGS. Review installation procedures and plan for frequent maintenance.

Important Considerations

The S8910U is NOT a replacement for:

• Intermittent pilot ignition controls.
• Direct spark ignition controls.
• Certain specific 120 Vac or 24 Vac hot surface ignition controls, especially those with different trial times or edge connectors.

For applications in demanding environments (commercial cooking, agricultural, industrial, high cycling, moisture, chemicals, dust, heat), consult Honeywell Home and Building Control Engineering.

Environmental Factors

• Frequent Cycling: Designed for 3-4 cycles/hour. High cycling rates may reduce lifespan. Monthly checkout recommended.
• Water or Steam Cleaning: Protect controls from water/steam. Mount controls high. NEMA 4 enclosure recommended. Replace wet modules.
• High Humidity/Dripping Water: Prevent water contact. Ensure adequate air circulation in humid environments. NEMA 4 enclosure recommended.
• Corrosive Chemicals: Avoid contact. NEMA 4 enclosure recommended if chemicals are suspended in air.
• Dust or Grease Accumulation: Use covers or NEMA 4 enclosure to limit contamination.
• Heat: Ensure ambient temperature does not exceed control rating. Use insulation/shielding/air circulation for high-temperature applications.

Installation Steps

1. Read instructions carefully.
2. Verify S8910U is a direct replacement using Tables 2, 3, and 4.
3. Installation must be performed by a trained, experienced service technician.
4. Perform checkout after installation.

WARNING: If module gets wet, it can malfunction, leading to explosive gas accumulation. Never install where water can flood, drip, or condense. Never use a wet module; replace it. LP gas is heavier than air; ensure area is free of gas before lighting or operating appliances. Do not disassemble or clean the module.

Mounting Recommendations

Mount the S8910U in the same location as the old module. Protect from moisture, chemicals, dust, and grease. Ensure ambient temperature is within the specified range. Mount with terminals facing down to protect from dust and dripping water. Terminals can also face sides, but NOT upwards. Refer to Fig. 2 for mounting positions.

Install Selection Tab

Select the correct tab (A, B, C, or D) based on Tables 1-4. Install the tab firmly on the module. Discard unused tabs safely. If no tab is installed, the module defaults to a 4-second trial time and one ignition trial.

Wire the Module

CAUTION: Disconnect power before wiring. Check appliance manufacturer's wiring diagrams. Ensure all wiring complies with electrical codes. Prevent igniter leadwires from contacting grounded metal surfaces. Ensure common ground for module, igniter, flame sensor, and burner. Verify transformer VA rating is adequate.

Connect wires according to Table 5 and Figs. 4-6. Use provided quick-connects as needed. Ensure proper system ground.

Table 5. Replacement Wiring Terminals

^a Remove quick-connect and replace with the included 1/4 in. quick-connect.
^b Use green adapter cable (provided) to connect S8910U GND (BURNER) terminal to chassis ground.
^c Do not use the S8910U VALVE (GND) terminal. VALVE (GND) and 24V (GND) are interconnected in the appliance wiring.
^d Remove quick-connect and replace with the included 3/16 in. quick-connect.
^e Do not use this terminal if model being replaced does not have 120V neutral power supply connection.
^f Use the black wire on the included adapter cable.
^g Use the orange wire on the included adapter cable.
^h On remote sense models, remove jumper quick-connect from S8910U sense terminal, cut jumper wire at circuit board and discard. On local sense models, leave black jumper connected.
ⁱ Remove jumper from S8910U sense terminal, cut jumper wire at circuit board and discard.

Wiring Diagrams

Refer to Figures 4, 5, and 6 for typical hookup diagrams when replacing White-Rodgers 50E/F47, Robertshaw HS780, and Honeywell S89/S890 modules, respectively. These diagrams illustrate specific connections and component placements.

Cross Reference Tables

The following tables provide cross-reference information for replacing older ignition modules with the S8910U.

Table 2. White-Rodgers Control to Honeywell S8910U Cross Reference

NOTE: Information based on 1991 White-Rodgers Product Catalog (R3700). Honeywell reserves the right to update this list.

^a S8910U and original control lockout times differ; S8910U time is within design tolerance.
^b S8910U lockout time is shorter than original. Observe appliance operation under various input conditions.

Table 3. Robertshaw Control to Honeywell S8910U Cross Reference

NOTE: Robertshaw product information from 1993-1994 Robertshaw Uni-Line Catalog (2-064).

^a S8910U and original control lockout times differ; S8910U time is within design tolerance.
^b S8910U lockout time is shorter than original. Observe appliance operation under various input conditions.

Table 4. Honeywell Control to Honeywell S8910U Cross Reference

^a S8910U and original control lockout times differ; S8910U time is within design tolerance.
^b S8910U lockout time is shorter than original. Observe appliance operation under various input conditions.

Startup and Checkout

WARNING: FIRE OR EXPLOSION HAZARD. FOLLOW ALL SAFETY WARNINGS. If gas smell or leak is suspected, turn off gas supply, evacuate building, and do not use electrical devices until area is clear. Perform gas leak test after installation or any work on gas piping.

Gas Control System Checkout

Checkout the gas control system:

• At initial installation.
• As part of regular maintenance.
• As the first step in troubleshooting.
• Any time work is done on the system.
• At maintenance intervals determined by the application.

Steps

1. Visual Inspection: With power off, check all wiring connections. Turn on power, open gas shutoff valves, and test for gas leaks upstream of the gas control.
2. Verify Control System Ground: Ensure common ground between the module, igniter, flame sensor, and main burner. Check for good metal-to-metal contact. Run a ground lead from the burner to ground if necessary.
3. Review Normal Operation: Refer to Operation and Application sections for normal sequence and specifications.

Operation

The S8910U is a direct ignition control for 120 Vac timed warmup hot surface igniters. It controls ignition and shuts off gas on ignition failure or loss of main burner flame.

Operating Phases

• Purge/Prepurge: Combustion air blower starts on call for heat. Air proving switch closes, energizing the S8910U. Initiates a 32-second prepurge delay.
• Igniter Warmup: Energizes the hot surface igniter for a 34-second warmup period. Gas control remains closed.
• Trial for Ignition: Gas control opens for the trial time set by the selection tab. Igniter stays powered for activation. Flame sensing circuit checks for flame. If flame is present, gas control stays open.
• Burner Operation: Flame rectification circuit maintains gas control open. Flame is monitored continuously.

Safety Shutdown

One Trial Selection Tabs (A and C): If flame is not sensed by the end of the trial, the gas control closes, and the module locks out. Requires manual reset (remove power or set thermostat below room temp for 30 seconds). If flame is lost during operation, module initiates a warmup and one trial; if still no flame, it locks out.

Three Trial Selection Tabs (B and D): If flame is not sensed on the first trial, a 96-second between-trial purge occurs, followed by warmup and a second trial. This repeats a third time. If flame is still not established after the third trial, the gas control closes, and the module locks out, requiring manual reset. If flame is lost during operation, module performs a between-trial purge, warmup, and trial sequence up to three times per call for heat before lockout.

Fig. 8. S8910U normal operating sequence.

This flowchart illustrates the step-by-step process from call for heat to burner operation or safety lockout, detailing prepurge, igniter warmup, trial for ignition, and flame sensing.

Troubleshooting

IMPORTANT: Follow appliance manufacturer service instructions. Meter readings must be taken during the trial for ignition period. Ignition module cannot be repaired; replace if malfunctioning. Service only by trained technicians.

Status LED

The LED indicates system status:

• Pulsing Heartbeat: Normal operation during call for heat (prepurge, warmup, trial, run).
• One Flash: Ignition lockout. Probable causes: burner failure to light, failure to detect flame. Check gas supply, voltage, igniter, gas control, wiring. If burner lights but goes out, check igniter/sensor, flame rod, ground connections, wiring.
• Two Flashes: Weak flame rectification signal. Probable causes: contaminated/mislocated igniter/sensor/flame rod, poor leadwire insulation, poor gas pressure. If signal is strong initially but weak during operation, check for overheating.
• Three Flashes: Internal error. Probable cause: S8910U logic failure. Replace the S8910U.

Ignition System Checks

1. Igniter Wire Harness: Ensure cable is not in contact with metal, connections are clean/tight, and continuity is good.
2. Ignition System Grounding: Check for common ground between module, igniter, sensor, and burner. Ensure good metal-to-metal contact. Check ground path continuity. Check igniter/sensor insulator temperature. Restore bent sensor/bracket to position. Replace cracked insulators.
3. Flame Sensing Circuit: Verify burner flame provides a good rectification signal. Ensure 3/4 to 1 inch of sensor/igniter-sensor is immersed in flame. Check for excessive temperature at the ceramic insulator. Check for cracked insulators. Ensure electrical connections are clean and tight. Replace damaged wire with appropriate type. Verify igniter meets minimum specifications if not Norton 201/271.

Fig. 9. S8910U troubleshooting sequence.

This flowchart guides users through diagnosing issues, starting with basic checks and progressing to specific component tests and potential module replacement.

Dimensions

Refer to Fig. 1 for approximate ignition module dimensions in inches (mm).

Approvals

IAS Design Certified: Report No. C2030018.