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X-XX UL

INSTALLATION INSTRUCTIONS

Copyright © 1998 Honeywell Inc.   •   All Rights Reserved

Piezo Envelope Assembly

PART NO. 396079

APPLICATION

The 396079 Piezo Envelope Assembly is a replacement
device used with the VS8420/21 and VS8510/20/21 gas
valves, that allows manual lighting of the pilot burner. The
piezo is mounted on the gas valve and lights the pilot
burner by creating a spark when the plunger is depressed.
The connecting wire includes a terminal to connect to the
electrode of the pilot burner.

The piezo envelope assembly includes the piezo, cover
and 2-screws.

INSTALLATION

When Installing this Product...

1. Read these Instructions carefully. Failure to follow

them could damage the product or cause a hazard-
ous 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 installation is complete, check out product

operation as provided in these Instructions.

Mounting and Wiring the Piezo

IMPORTANT

This installation requires working within the
combustion chamber, follow instructions carefully.

1.

Turn the knob on the gas valve to the OFF position.
See Fig. 1.

2.

Disconnect pilot burner wire from piezo wire.

3.

Remove the two screws from the cover.

4.

Remove and discard the existing; cover, piezo and
screws.

5.

Replace the existing piezo with the new piezo.

6.

Place the new cover over the new piezo.

7.

Screw the new screws into the new cover.

8.

Connect the pilot burner wire to the piezo wire.

Pilot Lighting Test

1.

Turn the knob on the gas valve 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 the knob counterclockwise

to the ON

position. On a call-for-heat, the main valve opens and
the main burner ignites.

Home and Building Control
Honeywell Limited-Honeywell Limitée
155 Gordon Baker Road
North York, Ontario
M2H 3N7

69-1206–1   L.C.  Rev.  9-98

Home and Building Control
Honeywell Inc.
Honeywell Plaza
P.O. Box 524
Minneapolis, MN 55408-0524

Printed in U.S.A. on recycled 
paper containing at least 10% 
post-consumer paper fibers.

www.honeywell.com

Fig. 1. Exploded view of the piezo assembly and pilot

burner connection with VS8520 gas valve.

LO

HI

OFF

ON

PILOT

M12899

PIEZO

M12896

PIEZO

COVER

SCREWS (2)

GAS CONTROL KNOB

OFF

ON

PILOT

TOP VIEW 
OF KNOB

69-1206-1

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