Honeywell VS8510/VS8520 Millivolt Combination Gas Control

PRODUCT DATA

FEATURES

• For use with 750mV thermopile generator.
• VS8510 has operator and power unit powered by 750mV thermopile generator.
• VS8520 has operator powered by 750mV thermopile and power unit powered by 30mV thermocouple.
• Vented and vent free models.
• Available with standard or high/low regulators.
• Capacity rated at 60,000 BTUH at 1" wc pressure drop. Maximum regulation capacity is 100 BTUH and minimum regulated capacity is 10 BTUH. All capacities are with side inlet.
• Adjustable servo regulator maintains almost constant gas outlet pressure over a wide range of gas supply pressures.
• Models available with 0°F to 175°F (-18°C to 79°C), -40°F to 175°F (-40°C to 79°C), 0°F to 225°F (-18°C to 107°C).
• Multiple inlet and output main gas connections with NPT or BSP.
• Multiple pilot outlet and thermocouple locations.
• European style inlet and outlet pressure taps.
• Programmed lighting sequence with safe lighting pilot system and safety shutoff.
• Fine mesh inlet screen included optional outlet screen.
• Multiple mounting holes can be mounted at any angle between 0 and 90 degrees from the top upright position (knob on top).
• Latching device interlock eliminates involuntary re-ignition of the main burner.
• Snap-open opening characteristics.
• Compact.
• ECO (Energy Cut-Off) option.

APPLICATION

The VS8510 and VS8520 are low capacity, compact size millivolt operated gas valves designed for use in small gas appliances burning either LP or natural gas. Primary appliance applications include gas fireplaces, fireplace inserts, log sets, free standing stoves, wall furnaces, and room space heaters. The VS8510 and VS8520 millivolt gas valves are approved in accordance with IAS (AGA and CGA).

Contents

• Application
• Features
• Specifications
• Ordering Information
• Installation
• Startup and Checkout
• Service
• Accessories

SPECIFICATIONS

IMPORTANT: The specifications given in this publication do not include normal manufacturing tolerances. Therefore, this unit may not exactly match the listed specifications. Also, this product is tested and calibrated under closely controlled conditions, and some minor differences in performance can be expected if those conditions are changed.

Models

The VS8510 circuit consists of a gas valve, thermopile, millivolt thermostat, and a pilot burner, powered by a 750mV thermopile generator. The VS8520 circuit includes a gas valve, quick dropout thermocouple, thermopile, millivolt thermostat, and a pilot burner. The VS8520 has its operator powered by a 750mV thermopile and its power unit powered by a 30mV Quick Dropout Thermocouple. Use the VS8520 when the appliance standard requires a gas valve with a fast dropout thermocouple.

Options

• High/Low Adjustable Pressure Regulator: Available on both models, providing a main burner regulator with preset maximum and minimum pressure settings for natural and LP gases. Offers infinite adjustment between minimum and maximum pressure settings.
• Convertible Pressure Regulator: Available on standard models only. Converts factory natural gas setting to LP gas setting by removing the regulator adjustment screw, adding an LP spring, and adjusting the screw for the desired outlet pressure.
• Outlet Screen: Wire mesh outlet screen prevents debris, such as thread dope, from entering the valve from the outlet opening.
• Inlet and Outlet Mounting Threads: Optional mounting threads are available on the inlet and outlet sides with M5X0.8 or #10-24 threads.
• Additional: Table 1 lists more model configuration identifications.

Table 1. VS8510/VS8520 Configurations

ORDERING INFORMATION

When purchasing replacement and modernization products, refer to the TRADELINE® Catalog or price sheets for the complete ordering number. The ordering number is determined by:

1. Model
2. Tip style
3. Type of gas
4. Accessories

For additional questions or information, contact:

1. Your local Home and Building Control Sales Office.
2. Home and Building Control Customer Relations, Honeywell, 1885 Douglas Drive North, Minneapolis, Minnesota 55422-4386.

In Canada: Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9. International Sales and Service Offices are located in principal cities worldwide. Manufacturing occurs in Australia, Canada, Finland, France, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, and U.S.A.

Model Voltage and Capacity

Table 2. VS8510/VS8520 Voltage and capacity ratings.

Regulation Capabilities

Table 3. HI/LO and Standard Regulator Specification Pressures in inches wc(kPa)

Main Gas Connection:

The Millivolt Combination Gas Control has a 3/8 in. thread, NPT or BSP.

Pilot Gas Connection and Flow:

• Connection size: 7/16-24 UNS.
• Flow 1700 Btuh/H at 4.0 in. w.c. inlet.
• Option M10x1 connection.

Pilot Location:

• Inlet side.
• Bottom.

Thermocouple Size/Connections:

• 11/32-32 UNS double lead.
• Outlet.
• Bottom.
• Option MM10x1 connection.

Inlet/Outlet Options:

• Straight through.
• Bottom.
• 3/8" x 3/8" NPT or BSP.

Thermocouple and Pilot:

Metric or UNS.

Ambient Temperature:

• 0°F to 175°F (-18°C to 79°C).
• Option for -40°F (-40°C), 225°F (107°C).

Shipping Temperature:

-40°F to 175°F (-40°C to 79°C).

Pressure Regulation:

Servo regulator with adjustable outlet pressure. Typically 3.5 in. wc for natural gas; 11 in. wc for LP.

Interrupter (ECO):

1/4 in. tab connectors.

Pressure Taps:

European style inlet and outlet.

Opening Characteristics:

Snap open.

Screens:

Fine mesh inlet screen standard; optional outlet screen.

Approvals:

• International Approval Services (IAS) Certificate: C2030022.
• European Community (CE) Certificate pending.
• Australian Gas Approval pending.

IAS Rated Capacity

• 60,000 BTUH at 1 in. wc pressure drop for side inlet.
• 50,000 BTUH at 1 in. wc pressure drop for bottom inlet.

PRESSURE DROP CAPACITY CURVE – NATURAL GAS

A graph titled 'PRESSURE DROP CAPACITY CURVE – NATURAL GAS' shows the relationship between gas flow rate (BTUH x 1K) on the x-axis and pressure drop (IN. W.C.) on the y-axis. Two lines represent 'BOTTOM INLET' and 'SIDE INLET' with pressure drop values ranging from 0.5 to 2.0 inches of water column and gas flow from 0 to 120 (x1K BTUH).

Diagrams and Dimensions

Dimensions (Figure 1)

Figure 1 illustrates the physical dimensions and connection points of the VS8510/VS8520 models. It shows top, bottom, and side views. Key dimensions include overall height (approx. 4-5/8 inches), width (approx. 4-1/8 inches), and depth (approx. 4-9/16 inches). Various ports are labeled: Inlet, Outlet, Pilot Outlet, Thermocouple Connection (top, bottom, side), Inlet Pressure Tap, Outlet Pressure Tap, HI/LO Regulator Adjustment, Pilotstat Knob, and Mounting Screw locations (accepting #10-24 or M5X0.8 screws). The ECO window is also indicated.

Sediment Trap Installation (Figure 2)

Figure 2 depicts the correct installation of a sediment trap in the gas supply line. It shows a horizontal gas supply line with a vertical drop, leading to a sediment trap, followed by a horizontal riser to the gas control. It emphasizes maintaining a minimum of 3 inches clearance for piping and the importance of smooth bends in metallic tubing.

Pipe Compound Usage (Figure 3)

Figure 3 illustrates the proper application of pipe compound. It shows pipe threads being inserted into the gas control, with the instruction to apply a moderate amount of good quality pipe compound to the pipe only, leaving the first two end threads bare. It also notes that for LP installations, compound resistant to LP gas should be used.

Top Views of Gas Control (Figures 4 & 5)

Figures 4 and 5 provide top views of the gas control with HI/LO regulator (Fig. 4) and standard regulator (Fig. 5). They clearly label the control knob positions (OFF, PILOT, ON), the pilot adjustment screw, the HI/LO regulator adjustment screw (under a cap screw), and the inlet and outlet pressure taps. Wiring terminals are also indicated.

Proper Wrench Usage (Figure 6)

Figure 6 demonstrates the correct method for using a wrench on the gas control. It shows applying the wrench to the bottom of the gas control, specifically to the shaded area, to prevent damage or distortion to the unit when connecting or disconnecting piping.

Wiring Diagrams (Figures 7 & 8)

Figure 7 shows the wiring diagram for the VS8520 Millivolt system with a quick drop-out thermocouple, illustrating connections between the millivolt thermostat, high limit control, Q313 thermopile, quick drop-out thermocouple, electrode, and the VS8520 HI/LO millivolt gas valve. Figure 8 shows the wiring diagram for the VS8510 Millivolt system without a quick drop-out thermocouple, connecting the millivolt thermostat, high limit control, Q313 thermopile, electrode, and the VS8510 HI/LO millivolt gas valve.

Safety Valve and Main Valve Operation Diagrams (Figures 9, 10, 11)

These figures illustrate the internal gas flow paths for the standing pilot millivolt valve in different operational states. Figure 9 (OFF-POSITION) shows all valves closed, with no gas flow. Figure 10 (PILOT-POSITION) shows the pilot valve open, allowing gas to flow to the pilot burner, while the main valve remains closed. Figure 11 (ON POSITION) shows both the pilot and main valves open, allowing gas to flow to both the pilot burner and the main burner. Key components like the pilotstat knob, power unit, servo valve, millivolt operator, safety valve, pilot tube, main valve, thermopile, electrode, and main burner are depicted.

INSTALLATION

When Installing this Product...

• Read these instructions carefully. Failure to follow them could damage the product or cause a life-threatening hazardous condition.
• Check the ratings given in the instructions and on the product to ensure suitability for your application.
• The installer must be a trained, experienced service technician.
• After installation, check product operation as provided in these instructions.

WARNING: Oxygen depletion hazard. Can cause injury or death due to asphyxiation.

• Use only vented gas valve models on vented appliances.
• Use only unvented gas valve models on unvented appliances.

WARNING: Fire or explosion hazard. Can cause severe injury or death and property damage.

• Disconnect power supply before wiring to prevent electrical shock or equipment damage.
• To avoid dangerous accumulation of fuel gas, turn off the gas supply at the appliance service valve before starting installation, and perform a Gas Leak Test after installation is complete.
• Always install the sediment trap in the gas supply line to prevent contamination of the gas control.
• Do not force the gas control knob. Use only your hand to turn it. Never use any tools.
• If the gas control knob does not operate by hand, the gas control should be replaced by a qualified service technician. Force or attempted repair can result in fire or explosion.

CAUTION: Equipment damage. Can burn out heat anticipator in thermostat. Never apply a jumper across or short the valve coil terminals.

IMPORTANT: These gas controls are shipped with protective seals over the inlet and outlet tappings. Do not remove the seals until ready to connect the piping.

Follow the appliance manufacturer instructions, if available; otherwise, use these instructions.

Converting Between Natural and LP Gas

WARNING: Fire or explosion hazard. Can cause severe injury or death and property damage.

• Do not use a gas control set for natural gas on an LP gas system or vice versa.
• When making a conversion, the main pilot burner orifices must be changed to meet the appliance manufacturer specifications.

Refer to the appliance manufacturer instructions for orifice specifications and changeover procedures. Gas controls are factory-set for natural (and manufactured) or LP gas. Do not attempt to use a control set for one gas type on the other. Gas controls with standard regulators can be converted using a conversion kit (ordered separately): Part no. 395991 for natural to LP, and part no. 395992 for LP to natural.

Location

Locate the combination gas control where it cannot be affected by steam cleaning, high humidity, dripping water, corrosive chemicals, dust, grease accumulation, or excessive heat. For proper operation, follow these guidelines:

• Locate the gas control in a well-ventilated area.
• Mount the gas control high enough to avoid exposure to flooding or splashing water.
• Ensure the ambient temperature does not exceed the ambient temperature ratings for each component.
• Cover the gas control if the appliance is cleaned with water, steam, or chemicals, or to avoid dust and grease accumulation.
• Ensure the gas control is not located where exposure to corrosive chemical fumes or dripping water can occur.

Install Piping to Gas Control

All piping must comply with local codes and ordinances or the National Fuel Gas code (ANSI Z223.1 NFPA No. 54), whichever applies. Tubing installation must comply with approved standards and practices.

• Use new, properly reamed pipe free from chips. Ensure tubing ends are square, deburred, and clean. All tubing bends must be smooth and without deformation.
• Run pipe or tubing to the control. If tubing is used, obtain a tube-to-pipe coupling to connect the tubing to the control.
• Install a sediment trap in the supply line to the gas control. See Figure 3.

Install Control

1. Mount the control 0 to 90 degrees from the upright position of the gas control knob, including vertically.
2. Mount the control so gas flow is in the direction of the arrow on the side of the control.
3. Thread pipe 9/16 in. into the control. Do not insert deeper than 3/8 in. to prevent valve distortion or malfunction.
4. Apply a moderate amount of good quality pipe compound (do not use Teflon tape) to the pipe only, leaving the first two end threads bare. For LP installations, use compound resistant to LP gas. See Figure 3.
5. Remove seals over control inlet and outlet, if necessary.
6. Connect pipe to control inlet and outlet. Use a wrench on either side of the pipe outlet. Refer to Figures 2 through 6.

Wiring

Follow the wiring instructions furnished by the appliance manufacturer, or use the general instructions provided below. If these instructions differ from the appliance manufacturer's, follow the manufacturer's instructions. For typical wiring diagrams, see Figures 8 and 9. All wiring must comply with applicable electrical codes and ordinances.

Disconnect power supply before making wiring connections to prevent electrical shock or equipment damage.

• Check the power supply rating on the gas control and ensure it matches the available supply. Install the transformer, thermostat, and other controls as required.
• This valve can only be used in a self-generating system.
• Adjust the thermostat heat anticipator to the 0.1A at 750 mV rating stamped on the valve operator.

STARTUP AND CHECKOUT

The Millivolt Gas Valve System has two configurations: The VS8510 includes a gas valve, thermopile, millivolt thermostat, and a pilot burner, with the thermopile driving the operator and power unit. The VS8520 includes a gas valve, quick drop-out thermocouple, thermopile, millivolt thermostat, and a pilot burner, where the thermopile drives the operator and the quick dropout thermocouple operates the power unit. Figures 9, 10, and 11 show how gas flow is controlled for each position of the control knob.

SERVICE

WARNING: Fire or Explosion Hazard. Can cause severe injury or death and property damage.

• Do not disassemble the gas control; it contains no replaceable components. Attempted disassembly or repair can damage the control.

CAUTION: Equipment Damage Hazard. Can burn out heat anticipator in thermostat. Do not apply a jumper across (or short) the valve coil terminals even temporarily.

If Main Burner Does Not Come On With Call For Heat

1. Confirm that the gas control knob is in the ON position.
2. Adjust the thermostat several degrees above the room temperature.
3. Use a DC voltmeter to measure the voltage across the THTP and TP terminals.
4. If no voltage is present, check the control circuit for proper operation.
5. If proper control system voltage is present, replace the gas control.

Warning to the Appliance Owner. For Your Safety, Read Before Lighting Appliance.

WARNING: Fire or Explosion Hazard. Can cause severe injury or death and property damage.

• Exactly follow the warnings and the lighting instructions.
• Before lighting, smell around the appliance area for gas. If the appliance uses LP (bottled) gas, smell next to the floor as LP gas is heavier than air. If you smell gas, immediately shut off the manual valve in the gas piping to the appliance or, on LP, at the tank. Do not try to light any appliance. Do not touch any electrical switch or use the phone. Leave the building and call your gas supplier. If your gas supplier cannot be reached, call the fire department.
• Do not force the gas control knob on the appliance. Use only your hand to turn it. Never use any tools. If the knob does not operate by hand, have a qualified service technician replace the control. Force or attempted repair can result in fire or explosion.
• The gas control must be replaced if it has been flooded with water. Call a qualified service technician.
• The gas control is a safety device and must be replaced in case of any physical damage such as bent terminals, missing or broken parts, stripped threads, or evidence of exposure to heat.

MAINTENANCE

WARNING: Fire or explosion hazard. Can cause severe injury or death and property damage.

• Do not attempt to take apart the gas control or to clean it. Improper assembly and cleaning can cause unreliable operation.

Regular preventive maintenance is important in applications that place a heavy load on system controls, such as those used in commercial cooking and agricultural and industrial industries, because:

• In many such applications, particularly commercial cooking, the equipment operates 100,000 to 200,000 cycles per year. Such heavy cycling can wear out the gas control in one to two years.
• Exposure to water, dirt, chemicals, and heat can damage the gas control and shut down the control system.

The maintenance program should include regular checkout of the system as outlined in the Checkout section, and checkout of the control system as described in the appliance manufacturer literature. Maintenance frequency must be determined individually for each application. Some considerations are:

• Cycling frequency: Appliances that may cycle 20,000 times annually should be checked monthly.
• Intermittent use: Appliances that are used seasonally should be checked before shutdown and again before the next use.
• Consequence of unexpected shutdown: Where the cost of an unexpected shutdown would be high, the system should be checked more often.
• Dusty, wet, or corrosive environment: Because these environments can cause the gas control to deteriorate more rapidly, the system should be checked more often.

Any control should be replaced if it does not perform properly on checkout or service. In addition, replace any module if it is wet or looks like it has ever been wet.

ACCESSORIES