See SERVICE PROCEDURE AG-II
THERMOCOUPLE TESTING
MAGNET ASSEMBLY TESTING (White Rodgers Control)
Page 13
Step 1. Following the lighting instruc tion label on the heater, p roceed to light the pilot an d allow to operate for
three minutes. If the pilot will not stay lit, hold the pilot butto n (located on the combination
thermostat/gas valve) down during this test
Step 2. Using a multimeter capable of me asuring millivolts, connect o ne lead
using an alligator clip to the copper sheath of the thermocouple, use the second lead of the multi meter to
probe the top terminal located at the back of the gas control.
Step 6. With a meter reading of 13 mi llivolts or greater, rot ate knob of gas control to t he
“OFF” position.
Step 7. The magnet should remain closed for a drop of at least 6 millivolts. You will here a “snap” or “click” sound
when the magnet opens, if you hear this sound prior to a drop of 6 millivolts, the magnet is out of
specification and the gas control should be replaced.
MAGNET ASSEMBLY TESTING (Robertshaw Control)
Step 1. Disconnect thermocouple from gas control.
Step 2. Connect a thermocouple adaptor
(BWC P/N 239-44642-00, R obertshaw P/N 75036) at the
thermocouple location in the ga s control.
Step 3. Reconnect thermocouple to adaptor. Make certain all connections
are tight (finger tigh t plus ¼” turn).
Step 4. Using a multimeter capable of me asuring millivolts, connect o ne
alligator clip to the set screw of the adaptor and the other alligator
clip to copper portion of the thermo couple.
Step 5. Following the lighting instruc tion label on the heater, p roceed to light the pilot an d allow to operate for
three minuets.
Step 6. With a meter reading of 13 mi llivolts or greater, rot ate knob of gas control to t he
“OFF” position.
Step 7. The magnet should remain closed for a drop of at least 6 millivolts. You will here a “snap” or “click” sound
when the magnet opens, if you hear this sound prior to a drop of 6 millivolts, the magnet is out of
specification and the gas control should be replaced.
Figure 21
Figure 22
Figure 20
Probe top terminal on back of
gas control
Alligator clip to copper sheath
of thermocouple
SERVICE PROCEDURE AG-III
Gas Control Testing and Replacement
For Models using White Rodgers or
Robertshaw Gas Control
13