Honeywell VS8521 Installation Instructions Manual Download Page 7

VS8521 VENTFREE MILLIVOLT GAS VALVE

7

69-1223—1

SERVICE

WARNING

Fire or Explosion Hazard.
Attempted disassembly or repair can cause 
property damage, severe injury or death.
Do not disassemble the gas valve; it contains no 
replaceable components.

CAUTION

Equipment Damage.
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 valve.

WARNING TO THE APPLIANCE 
OWNER. FOR YOUR SAFETY, READ 
BEFORE LIGHTING APPLIANCE.

WARNING

Fire or Explosion Hazard.
Can cause property damage, severe injury 
or death.
Exactly follow the instructions for Pre-Lighting 
Checks.

Pre-Lighting Checks

1.

Before lighting, smell around the appliance area for 
gas. If the appliance uses LP gas, be sure to smell 
next to the floor because LP gas is heavier than air.

2.

If you smell gas, immediately shut off the manual 
valve in the gas piping to the appliance or, on LP, at 
the tank. Leave the building immediately and call 
your gas supplier. If your gas supplier cannot be 
reached, call the fire department.

3.

Do not force the gas valve control knob. Use only 
your hand to turn the control knob.

4.

If the knob does not operate by hand, the valve 
should be replaced by a qualified service 
technician.

5.

The gas valve must be replaced if it was flooded 
with water. Call a qualified service technician.

6.

The gas valve is a safety device. It must be 
replaced in the event of any physical damage such 
as bent terminals, missing or broken parts, stripped 
threads, or evidence of exposure to heat.

IMPORTANT

Follow the operating instructions provided by 
the manufacturer of your heating appliance.

Summary of Contents for VS8521

Page 1: ...2 European Community CE Certificate Applied for INSTALLATION When Installing this Product 1 Read these instructions carefully Failure to follow them could damage the product or cause a hazardous condition 2 Check the ratings given in the instructions and on the product to make sure the product is suitable for your application 3 Installer must be a trained experienced service technician 4 After ins...

Page 2: ... comply with approved standards and practices 1 Use new properly reamed pipe free from chips When tubing is used assure the ends are square deburred and clean All tubing bends must be smooth and without deformation 2 Run pipe or tubing to the valve If tubing is used obtain a tube to pipe coupling to connect the tubing to the valve 3 Install sediment trap in the supply line to the gas valve See Fig...

Page 3: ...nect power supply before making wiring connections to prevent electrical shock or equipment damage 1 Check the power supply rating on the gas valve and make sure it matches the available supply Install the transformer thermostat and other controls as required 2 This valve can be used only in a self generating system 3 Adjust the thermostat heat anticipator to the 0 1A at 750 mV rating stamped on t...

Page 4: ...lve counterclockwise to the PILOT position push the knob down and hold in position The pilot valve opens and allows gas to flow to the pilot burner 2 Push the plunger on the piezo until the pilot burner is lit Hold down the knob until a strong flame is present approximately 60 seconds 3 Release the knob The shaft will move upward and engage the safety valve lever that opens the safety valve 4 Turn...

Page 5: ...ner HI LO Manually adjusts outlet pressure NOTE Valves are shipped with the gas control knob in the ON position Perform Gas Leak Test WARNING Fire or Explosion Hazard Can cause property damage severe injury or death Stand away from the main burner while lighting Hidden gas leaks can cause flashbacks in the appliance vestibule Check for gas leaks with rich soap and water solution any time work is d...

Page 6: ...perly MAINTENANCE WARNING Fire or Explosion Hazard Can cause property damage severe injury or death Do not attempt to take apart the gas valve or 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 the commercial cooking and agricultural and industrial ind...

Page 7: ...zard Can cause property damage severe injury or death Exactly follow the instructions for Pre Lighting Checks Pre Lighting Checks 1 Before lighting smell around the appliance area for gas If the appliance uses LP gas be sure to smell next to the floor because LP gas is heavier than air 2 If you smell gas immediately shut off the manual valve in the gas piping to the appliance or on LP at the tank ...

Page 8: ...C Thermocouple Have thermostat contacts open and pilot lit with Pilotstat knob turned to PILOT Reading should be a minimum of 12 mV in a new ODS pilot burner assembly If the reading is less than 12 mV replace the ODS pilot burner assembly The power unit will hold in down to 3 mV If the output of the thermocouple is less than 3 mV replace the ODS pilot burner assembly 4 Test D Operator Pull In have...

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