Vulcan-Hart VL3GMS Manual

A SERVICE OF

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VL SERIES STEAMER - SERVICE PROCEDURES AND ADJUSTMENTS

Pa

g

e 30 of 88

NOTE: If adjustments in

g

as or pilot pressure

settin

g

s are made, always replace the adjustment

cover screw to assure proper

g

as control operation.

If the adjustment does not result in a pilot flame of

proper size, then

g

as mi

g

ht not be flowin

g

properly

to the pilot. Check for a plu

gg

ed pilot orifice, a

kinked or plu

gg

ed pilot

g

as supply tube and for low

g

as supply pressure. The pilot operates unre

g

ulated

at

g

as supply pressures while the pressure re

g

ulator

in the combination control valve re

g

ulates pressure

to the main burners only. Visually check the

thermocouple tip (hot end) and tube lead for kinks or

pinches that mi

g

ht be causin

g

a short between the

tube and the wire inside. Also, check the threaded

connector tip for corrosion, tarnish or dirt which can

cause a poor connection. If the thermocouple shows

either of these si

g

ns, it should be replaced with a

new one.

NOTE: The connection of the tubin

g

from the

thermocouple tip to the control valve is an electrical

connection and must be clean. Do not use any

sealin

g

compound on the threads or over ti

g

hten the

threaded connection. Fin

g

er ti

g

hten the nut plus 1/4

turn with a wrench. Over ti

g

htenin

g

the nut could

crush the insulator, shortin

g

the thermocouple.

If the pilot flame is correct and there are no drafts,

then the problem is in the thermocouple output

volta

g

e or the

g

as solenoid valve in the combination

control.

Check the thermocouple output volta

g

e as follows:

1. Turn the power switch OFF and disconnect the

thermocouple from the

g

as combination control

valve.

2. Check the thermocouple DC millivolt output

with a VOM. If a meter is not available, replace

the thermocouple with a new one and check

operation a

g

ain.

A. Install a thermocouple adaptor into the

connection on the

g

as combination control

valve. Screw the thermocouple in to the

adaptor then connect the meter leads to it.

See “TOOLS” under “GENERAL” for

information on thermocouple adaptor. If a

thermocouple adaptor is not available then

turn the power switch OFF, disconnect the

thermocouple from the

g

as combination

control valve and proceed to step 2D.

B. Turn the power switch ON and li

g

ht the

pilot. Allow the pilot to heat the

thermocouple for one to two minutes and

take a closed

circuit readin

g

. Compare the

readin

g

s with the chart below.

1) If the readin

g

is less than the

minimum or thermocouple is not

operatin

g

as described, replace the

thermocouple as outlined under

“PILOT AND THERMOCOUPLE

ASSEMBLY (GAS MODELS)” in

“REMOVAL AND REPLACEMENT

OF PARTS” then check for proper

operation.

2) If the readin

g

is within the ran

g

e listed

in the chart below then thermocouple

is operatin

g

properly. Reconnect the

thermocouple to the

g

as combination

control valve.

3) If after replacin

g

thermocouple, the

pilot or main burners are still not

functionin

g

properly, then a problem

in the

g

as combination control valve

exists as well. Replace the

combination control valve as outlined

under “GAS COMBINATION

CONTROL VALVE” in “REMOVAL

AND REPLACEMENT OF PARTS”

then check for proper operation.

C. Turn the power switch OFF and

disconnect the thermocouple adaptor from

the

g

as combination control valve and

thermocouple.