Desa B350D Service Manual page 20

H I G H P R E S S U R E P O R T A B L E F O R C E D A I R H E A T E R S E R V I C E M A N U A L
D. Defective fan switch
1. Unplug heater.
2. Remove upper shell of heater.
3. Remove fan switch from heater.
4. Set ohmmeter to RX1K scale.
5. Connect test leads from ohmmeter to
terminals marked 1 and 3 on fan switch.
The ohmmeter should move upscale and
read continuity (0 ohms). Note: Make
sure fan switch is at room temperature
before performing this test.
3
Figure 28 - Testing Terminals 1 and 3
20
2
Figure 27 - Fan Switch
of Fan Switch
6. Connect test leads from ohmmeter to
terminals marked 1 and 2 on fan switch.
Figure 29 - Testing Terminals 1 and 2
1
7. Apply a low level of heat to the face of the
switch. Do this with a lit match, heated
soldering iron, etc. Ohmmeter should
read continuity (0 ohms) when fan switch
is heated.
8. Replace fan switch if any of these condi-
tions are not met during testing.
E. Incorrect fuel pump pressure
Follow steps under INCORRECT FUEL PUMP
PRESSURE, procedure "C" on page 13.
F. Dirty fuel filter
Follow steps under DIRTY FUEL FILTER,
procedure "H" on page 17.
G. Dirty photocell
Follow steps 1 thru 5 under DEFECTIVE OR
DIRTY PHOTOCELL, procedure "B" on page
19.
of Fan Switch