Lochinvar 399 - Manual (Page 63)

Installation and
Service Manual
63
Step 1
Does the power
switch provide
power to the
control panel?
Check the switch and/or
the line voltage.
Step 1
Does the power
switch provide
power to the
Check the switch and/or
the line voltage.
NO
YES
Combustion air
blowers come on.
NO
Is there 24VAC at B2 on
the terminal strip.
Check 24VAC at TH
(orange wire) on ignition
module(s).
Check all safety limit
devices and voltage from
the transformer to B2.
NO
Does F2 on ignition module
have 120VAC? YES
YES
NO
Exchange ignition
module.
Check fan relay
board. Is there
120VAC on red
wires, pins #7 &
#9?
NO
YES
Is there continuity from the fan
relay board to fan(s)?
Replace fan
relay board.
Replace fan.
YES
Status light(s) does
not blink 1 flash
continuous. Check air pressure
switch 24VAC on tan
wire (N.O.)
NO
24VAC at PS (tan wire) at ignition module
and/or connector plug for proving relay secure.
NO
YES
Check air pressure
switch for correct
pressures. YES
Replace air pressure
switch.
NO
Correct air settings
may have to clean
burners/heat
exchanger.
YES
Does
igniter(s)
proof?
NO
Check Amp draw for 3.1 amps or
greater.
NO
Is Air Switch
bouncing? YES
Replace igniter if less than 2.75 amps.
YES
YES
Step 2
Step 3
Step 4
YES
YES
Check flow switch, all connectors
behind control panel and Tekmar
output pins #16 and/or #20.
NO
Do the gas valve(s)
open and getting
24VAC?
Is the flame sense
signal to the ignition
module 5uA dc or
greater?
NO YES
Check inlet/manifold gas pressure
both static and dynamic. Check
down draft.
NO
Is 24VAC present at the main unit connector
(3x5 amp plug) red and/or red - black wire,
block position #01 and #02?
YES
Replace gas valve.
NO
Check voltage at fan relay
board. No Voltage at pins #10
(red) and/or #02 (red-orange)
check ignition module pin #05
(replace RLY2402 if no
voltage). No Voltage at pins
#08 (red-black) and/or #03
(red-white) check Tekmar
controller pins #17-18 (red-
black) and/or #21-22 (red-
white) input/output voltage.
YES
Unit is running.
NO
Call our Technical
Service Department
1-800-722-2101
Step 6
Step 5
TROUBLESHOOTING GUIDE
990,000 - 2,070,000 Btu/hr Models