TurboChef NGO/SOTA - Measuring RF Leakage for Microwave Safety; Troubleshooting

22 OVEN SY
STEMS
Measuring RF Leakage for Microwave Safety
W
ARNING: This procedure requires work with
hot sur
faces and water loads.
T
o avoid burns, be
car
eful when testing.
An RF (microwave) leakage test must be performed
at the conclusion of the follo
wing ser
vice tasks:
- Door removal, replacement and/or adjustment
-
W
aveguide removal and/or replacement
- Magnetron removal and/or replacement
-
Door switch adjustment and/or replacement
WARNING: If the unit fails the microwave
leakage test (leakage greater than 5mW/cm
2
),
the oven must be taken out of service
immediately until the defect is corrected. In
addition, the CDRH R
egulation 21 Subpart C,
1002.20 r
equires that leakage readings of over
5mW/cm
2
must be r
eported to the manufacturer.
To measure RF leakage,
1.
Turn the oven on (page 8) and allow it to warm
up to the set temperatur
e (approximately 15
minutes if the o
ven starts cold).
2. Once the oven has warmed up, place the oven
in Test Mode (see page 13). From Test Mode,
select M
anufacturing M
ode.
3.
F
rom the Manufacturing Mode screen, select
“MW Leak
T
est” and follow the instructions on
the screen (also detailed in the following steps).
4. Place a water load into the cook cavity. The
water load must conform to the follo
wing
specifications:
-
V
olume: 275 ml ± 15 ml
- Temperature: 68
º
F ± 9
º
F (20
º
C ± 5
º
C)
- Vessel: Low form, 600 ml beaker with an
inside diameter of approximately 3.35" (85
mm) and made of P
yrex or equivalent.
5.
Close the o
ven door and press the Enter key.
The microwave system will turn on.
6. Measure microwave emission around the door as
sho
wn in Figure 30, moving the meter sensor at
0.5 inches/second.
7. As microwave leakage is observed while moving
the sensor
, note any meter spike ar
eas that come
close to 5mW/cm
2
for later re-measurement.
8. Replace the water load every 60 seconds until
the test is completed, and also after scanning
the door.
9. Close the oven door and return the meter probe
to any “
meter spike
” areas and allow the probe to
remain in the “spike” area for 17 seconds. Note
the highest reading obtained.
NO
TE:
There may be several places on the door
where this procedure needs to be done. If so, start
out with a fr
esh water load each time a ne
w area is
measur
ed, or if measurement of an area takes longer
than 60 seconds.
10.
After each test is complete, open the o
ven door
and dispose of the hot water.
Troubleshooting
The following faults may occur in relation to the
oven door:
-
F4: Monitor (see page 36)
The follo
wing issues may occur in r
elation to the
oven door:
- “Cook Door Open” message when door is
closed (see page 39)
Figure 30: Survey Meter Placement