SG4D

Overview

The Vulcan Hart SG4D is a single-deck, full-size gas convection oven with electric ignition. Its solid-state temperature controls regulate oven heat, while a two-speed fan circulates air through the porcelain-lined cavity. A power-level control adjusts heat input, and the SG4D includes a 60-minute timer. The service manual identifies the SG4D as model ML-114875.

The oven is supplied with five racks and has an operating capacity of up to six racks. Eleven-position rack supports allow different rack arrangements for baking, broiling, reheating and roasting. The manual also describes the SG4D as having independently opening doors with a window as standard; other door arrangements are listed as options for the SG series.

Key Features

• Gas convection heat: Two 30,000 BTU/hr burners provide a combined rated input of 60,000 BTU/hr.
• Adjustable heat input: The power-level control varies burner input. The manual says the control must be on for the oven to operate.
• Two-speed fan: The 1/2 HP electric motor provides two fan speeds to adjust air velocity in the oven.
• Solid-state controls: The SG4D has a solid-state temperature controller and a 60-minute timer. A five-hour timer is listed as an option.
• Rack flexibility: Five racks are supplied, with capacity for six operating racks and eleven rack-support positions.
• Construction: The manual describes a porcelain interior and stainless-steel exterior panels.
• Listing information: The Wasserstrom listing excerpt identifies this SG4D as NSF approved.

Specifications

• Model: SG4D, ML-114875.
• Equipment type: Single-deck gas convection oven with electric ignition.
• Gas input: 60,000 BTU/hr on natural gas or propane; the manual specifies two 30,000 BTU/hr burners.
• Manifold pressure: Natural gas, 3.5 inches water column; propane, 10 inches water column.
• Electrical service: 120 V, 60 Hz, single phase, 7.5 A; optional 208 V, 60 Hz, single phase, 3.6 A; or 240 V, 60 Hz, single phase, 3.75 A.
• Motor: Two-speed, 1/2 HP electric motor.
• Controls and timer: Solid-state temperature controls; 60-minute timer, with a five-hour timer listed as an option.
• Racks: Five supplied; maximum operating capacity of six racks; eleven-position rack supports.
• Interior: Porcelain.
• Height and weight: The supplied Wasserstrom excerpt lists a height of 58.75 and weight of 590, but does not show units.

Installation & Requirements

Location and clearances

The SG4D manual says the installation location must provide room for servicing and operation, keep combustion and ventilation air paths unobstructed, and provide adequate air to support gas combustion. The oven should not be exposed to fans blowing directly at it or cross-currents from nearby windows or wall fans.

For combustible construction, the manual specifies minimum clearances of 1 inch at the left side, 4 inches at the right side and 6 inches at the rear. For non-combustible construction, the specified clearances are 0 inches at the left side, 4 inches at the right side and 6 inches at the rear. The manual says the oven may be installed on combustible floors.

Gas, electrical and ventilation connections

Before installation, the manual instructs the installer to check that the available electrical service and gas type—natural gas or propane—match the oven’s rating plate. The gas inlet is at the rear. The gas supply line must be at least equivalent to 3/4-inch iron pipe, and the manual specifies a shutoff valve in the gas line ahead of the oven. It states that the oven has a regulator integral to the gas solenoid valve and requires no external regulator. The specified manifold pressures are 3.5 inches water column for natural gas and 10 inches water column for propane. Check gas joints for leaks with soap and water solution; the manual says not to use an open flame.

The manual lists standard electrical service as 120 V, 60 Hz, single phase and gives 208 V and 240 V single-phase options. It states that units with a flexible power cord have a three-prong grounding plug that must connect to a properly grounded three-prong receptacle; do not remove the grounding prong.

The flue is at the rear and must not be obstructed. The manual recommends venting flue gases outside through a ventilation system installed by qualified personnel. If a hood ventilation system is used, it specifies at least 18 inches between the flue termination and the hood filters. For Canadian installation, the manual refers to local codes, CAN/CGA-B149.1 for natural gas or CAN/CGA-B149.2 for propane, and Canadian Electrical Code CSA C22.2 No. 3.

Operation

Controls and cooking

The control panel includes a master switch with OFF, ON and OVEN COOL positions; a thermostat; a power-level control; a timer; a two-speed fan switch; and a light switch. The fan switch selects air velocity, while the light switch turns the oven lights on or off. The timer selects cooking-cycle time and sounds continuously when the countdown reaches zero. The timer does not turn the oven off; turn it to OFF to silence the buzzer. Keep it at OFF when the oven is not in use.

For the SG4D lighting procedure, the manual directs the operator to turn on the main gas supply and the gas control valve behind the small lower-front-panel door, then switch the master control on and set the thermostat to its maximum setting. The manual’s control-panel instructions say that if the burner fails to light, turn the gas off and wait five minutes before retrying. The oven and its parts become hot during operation, so use care when operating or handling it.

Before first use, wipe the interior and racks with a clean damp cloth. The manual then calls for closing the doors, switching the master control on, setting the thermostat to 300°F and allowing the oven to cycle for six to eight hours to release odours from new surfaces.

Rack arrangements and cooking uses

The manual gives recommended rack positions for different loads. Five racks in positions 2, 4, 6, 8 and 10 are recommended for broiling, cookies or reheating frozen lunches at maximum capacity, and for general baking of sheet-pan products no more than 2 1/2 inches high. Four racks in positions 1, 4, 7 and 10 suit general baking in sheet pans, muffin pans, pie or cake tins, and pudding pans with products up to 4 inches high. Three racks in positions 1, 5 and 9 are suggested for loaf or tube pans, breads, cakes and deeper casseroles or roasting pans. Two racks in positions 1 and 6 are recommended for turkeys and roasts up to 7 inches high.

For roasting, the manual gives a general temperature range of 225°F to 325°F for beef, lamb, poultry and ham, and 325°F for fresh pork. Its examples include standing rib roast at 250°F, rolled rib roast at 275°F, veal roast and turkey at 300°F, and meat loaf at 350°F. The baking guidance includes sheet cakes, angel food or sponge cakes, cupcakes, frozen fruit pies, and pumpkin or custard pies, with settings varying by product and load.

Cleaning & Maintenance

Before cleaning, disconnect electrical power, tag the disconnect switch to show that work is being done, and allow the oven to cool. Clean the stainless-steel exterior panels daily with a damp cloth; detergent may be used for stubborn soil. Rinse and dry with a soft, clean cloth. Clean the porcelain interior daily with soap or detergent and water, then rinse and dry. The manual cautions against using “Dawn.”

Racks and rack supports may be removed for cleaning. For burned-on food or grease that resists soap and water, the manual permits an abrasive cleanser mixed into a paste, applied with stainless-steel wool or a sponge while rubbing with the grain. Rinse with clear water and dry with a soft cloth. Do not use scouring powder on the glass window, as it can scratch and fog the glass.

Keep the snorkel tube opening clear. The manual says to check it for foil particles if aluminum foil is commonly used and to clean the tube with standard oven cleaner at least once a week. Rinse off all cleaning solution before operating the oven again. The manual also recommends running the oven at 400°F for 20 minutes before use to burn off any cleaning solution that was not thoroughly rinsed. To clear lingering odours after cooking at low temperatures, it describes running the unloaded oven at 500°F with the power-level control at 10 for 30 to 45 minutes.

The fan motor bearings are sealed and require no lubrication. Periodically check the flue for obstructions when the oven is cool. For lamp replacement, allow the oven to cool, remove the racks, unscrew the glass dome from the lamp body, replace the bulb and reassemble. The manual warns that the oven and its components are hot and that electrical power must be disconnected before maintenance.

Troubleshooting

The service manual is written for trained service technicians. It lists the following possible causes for common symptoms; gas and electrical service work should be handled by appropriately qualified personnel.

• Blower does not run in OVEN COOL or ON: Possible causes include line voltage, a faulty power/master switch or fan switch, interconnection wiring, or the blower motor.
• Blower runs in OVEN COOL but not ON: Possible causes include the door switch, power/master switch contacts or interconnecting wiring.
• Blower runs in ON but not OVEN COOL: Possible causes include the power/master switch or interconnecting wiring.
• Gas does not ignite and there is no spark: Possible causes include a shorted igniter/flame-sense electrode, an open igniter cable, heat relay, blower centrifugal switch, transformer, open high-limit thermostat, wiring or ignition module.
• Spark is present but gas does not ignite: Check possible causes listed in the manual, including a gas solenoid valve that is off or inoperative, a closed manual gas valve, gas supply that is off or at insufficient pressure, wiring or the ignition module.
• Gas ignites but the flame does not stay on: Possible causes include igniter lead connections, igniter grounding, an inoperative or maladjusted igniter/flame sensor, insufficient gas pressure, a plugged or obstructed snorkel vent, or incorrect transformer polarity to the ignition module.
• Oven does not heat or is not hot enough: The troubleshooting section lists possible control, probe, high-limit, power-level, gas-pressure, orifice, timer and wiring issues, depending on the symptom and model configuration.
• Uneven cooking: Possible causes include fan motor speed or direction, poor combustion, incorrect gas pressure, an obstructed exhaust or snorkel vent, or missing or damaged airflow baffles.
• Intermittent problems: The manual lists high ambient temperatures, loose wiring connections and a malfunctioning cooling fan as possible causes.

Applications

The SG4D’s rack positions and the manual’s cooking guidance support commercial baking, broiling, roasting, reheating and batch cooking. Example uses in the manual include sheet cakes, breads, cookies, pies, casseroles, meat dishes, turkeys and other roasts. Select rack positions and temperature settings for the product and load being cooked.