![background image](http://html1.mh-extra.com/html/desa/vp20btb/vp20btb_safety-information-and-installation-manual_2485638015.webp)
www.desatech.com
121880-01B
15
oPeRaTIoN
Continued
• If control knob does not pop up when
released, contact a qualified service
person or gas supplier for repairs.
Note: If pilot goes out, repeat steps 4 thru
7. Wait one (1) minute before lighting pilot
again.
9. Turn control knob counterclockwise
to desired heating level. The main burner
should light.
10. To leave pilot lit and shut off burner only,
turn control knob clockwise
to the
PILOT position.
CAUTION: Do not try to ad-
just heating levels by using the
equipment shutoff valve.
TO TURN OFF GAS
TO APPLIANCE
Shutting Off Heater
1. Turn control knob clockwise
to the
OFF position.
2. Turn off all electric power to the appliance
if service is to be performed.
3. Close equipment shutoff valve (see Figure
16, page 13).
THERMOSTAT
CONTROL OPERATION
The thermostatic control used on these
models differs from standard thermostats.
Standard thermostats simply turn on and off
the burner. The thermostat used on this heater
senses the room temperature. The thermostat
adjusts the amount of gas flow to the burner.
This increases or decreases the burner flame
height. At times the room may exceed the
set temperature. If so, the burner will shut
off. The burner will cycle back on when room
temperature drops below the set temperature.
The control knob can be set to any heat level
between 1 and 5. Selecting the 5 setting will
cause the burner to remain fully on without
modulating down in most cases.
Note: The thermostat sensing bulb mea-
sures the temperature of air near the heater
cabinet. This may not always agree with
room temperature (depending on housing
construction, installation location, room size,
open air temperatures, etc.). Frequent use of
your heater will let you determine your own
comfort levels.
MANUAL LIGHTING
PROCEDURE
1. Remove front panel (see Figure 7, page 9).
2. Follow steps 1 through 7 under
Lighting
Instructions
, page 14.
3. With control knob pressed in, strike match.
Hold match to pilot until pilot lights.
4. Keep control knob pressed in for 30 sec
-
onds after lighting pilot. After 30 seconds,
release control knob. Now follow step 9,
under
Lighting Instructions
, page 14.
5. Replace front panel.
INsPeCTING HeaTeR
Check pilot flame pattern and burner flame
pattern often.
PILOT FLAME PATTERN
Figure 21 shows a correct pilot flame pattern.
Figure 22 shows an incorrect pilot flame pat
-
tern. The incorrect pilot flame is not touching
the thermocouple. This will cause the thermo
-
couple to cool. When the thermocouple cools,
the heater will shut down.
If pilot flame pattern is incorrect, as shown
in Figure 22
• turn heater off (see
To Turn Off Gas to Ap-
pliance
)
• see
Troubleshooting
, page 17
Note: The pilot flame on natural gas units will
have a slight curve, but flame should be blue
and have no yellow or orange color.
Figure 22 - Incorrect Pilot Flame Pattern
Figure 21 - Correct Pilot Flame Pattern
Thermocouple
Pilot Burner
Pilot Burner
Thermocouple
Blue Flame
Yellow Flame