60-2034—7
10
RA890F
SERVICE • TROUBLESHOOTING
Service
GENERAL SERVICE
1. Only qualified personnel should attempt to service
heating equipment or controls.
2. Perform all checks required in the Checkout section
when replacing the RA890, or when relighting or restoring
power to the system after shutdown.
3. The captive mounting screws carry current; always
disconnect power before loosening or tightening the mount-
ing screws.
4. On each service call, check the controller for the ap-
proximately correct calibration and differential; assure that it
is mounted securely. (See controller instructions.)
5. Never use oil on any part of the RA890F.
6. When cleaning the burner, clean the flame detector.
7. Do not manually push in the RA890 relays. This may
damage the relays and it is an unsafe practice because it
overrides the protective features of the relay. Clean relay
contacts only as instructed below.
PERIODIC MAINTENANCE
The specific maintenance schedule setup depends on
several factors including type of equipment being controlled,
operating conditions (dirt and heat especially), cost of a
nuisance shutdown, etc. The following should be included in
any program:
1. Replace the vacuum tubes in the C7012 Flame Detec-
tor (when used) annually.
2. Perform a flame failure check and pilot turndown test
whenever the burner is serviced, and at least annually.
3. Inspect and clean the detector and any viewing win-
dows as often as required by soot accumulation and heat
conditions at the detector.
4. Perform a flame current check at least monthly and
more often when a shutdown may be costly.
5. Clean contacts only when required by failure to oper-
ate properly.
CONTACT CLEANING
Clean the relay contacts on the RA890 only when re-
quired and then only with Honeywell part no. 132569 Con-
tact Cleaner. The contact cleaner comes in pressurized spray
cans; directions for its use are printed on the can. Do not use
other commercial contact cleaners. Most cleaners tested
were found to leave deposits on the contact surfaces or to
attack RA890 chassis parts.
Troubleshooting
When trouble occurs in the heating system and its cause is
not immediately apparent, the service technician can apply
the following step-by-step checkout to locate the cause of
most problems. Refer to Fig. 3 and 4 for terminal locations,
and to Fig. 6 for location of component parts.
CAUTION
Use extreme care troubleshooting the RA890F;
line voltage can be present on most terminals when
power is on.
TEST STANDBY OPERATION
1. Set controller not to call for heat.
2. Reset the safety switch by pushing in and then releas-
ing the green safety switch reset button.
3. Close the line switch.
4. Check for line voltage at terminals 2 and 6. (Voltage
will be zero when a line voltage controller is used; check for
line voltage when controller is set to call for heat.)
a. Voltage must be 10 to -15 percent of the rated
voltage.
b. When voltage is zero (with low voltage controller), be
sure limit switch contacts are closed and check power
supply. Check for blown fuses, open circuit, or open
disconnect switch.
5. Check position of flame relay. (When a line voltage
controller is used, observe the action of the flame relay on a
call for heat.)
a. If the flame relay is out, proceed to step 6.
b. If the flame relay is pulled in, check for a flame simulat-
ing condition.
(1) Insert flame simulator plug or part no. 196146
Cable Plug into the test jack; do not ground the
other end.
(2) If flame relay holds in, replace the RA890.
(3) If flame relay drops out, trouble is in the flame
detector or external circuit. Check for light reach-
ing the photocell, hot refractory hold-in, or defec-
tive wiring.
TEST STARTING OPERATION
6. Set controller to call for heat . (If control uses a line
voltage controller, go back to steps 4 and 5.)
7. Observe load relay for pull-in.
a. Load relay pulls in to light pilot and start burner—
proceed to step 11.
b. Load relay does not pull in—proceed to step 8.
c. Load relay pulls in but does not light or burner does
not start—proceed to step 10.
8. Check line voltage controller, if used, and the limit; if
the load relay does not pull in, check again for power at