507716-01
Page 54 of 58
Issue 1717
Planned Service
A service technician should check the following items
during an annual inspection. Power to the unit must be
shut off for safety.
Fresh air grilles and louvers
(on the unit and in the
room where the furnace is installed) - Must be open and
unobstructed to provide combustion air.
Burners
- Must be inspected for rust, dirt, or signs of water.
Vent pipe
- Must be inspected for signs of water, cracked,
damaged or sagging pipe, or disconnected joints.
Unit appearance
- Must be inspected for rust, dirt, signs of
water, burnt or damaged wires, or components.
Blower access door
- Must be properly in place and
provide a seal between the return air and the room where
the furnace is installed.
Return air duct
- Must be properly attached and provide
an air seal to the unit.
Operating performance
- Unit must be observed during
operation to monitor proper performance of the unit and
the vent system.
Combustion gases
- Flue products must be analyzed and
compared to the unit specifications.
Problems detected during the inspection may make it
necessary to temporarily shut down the furnace until the
items can be repaired or replaced.
Instruct the homeowners to pay attention to their
furnace.
Situations can arise between annual furnace
inspections that may result in unsafe operation. For
instance, items innocently stored next to the furnace may
obstruct the combustion air supply. This could cause
incomplete combustion and the production of carbon
monoxide gas.
Table 13. Diagnostic Codes
Red LED Flash
Code
Diagnostic Codes / Status of Furnace
LED Off
No power to control or control hardware
fault detected
Heartbeat
Control powered - displayed during
all modes of operation if no errors are
detected
1 Flash
Reverse line voltage polarity
2 Flashes
Improper earth ground
3 Flashes
Burner failed to light, or lost flame during
heat demand
4 Flashes
Low flame signal - check flame sensor
5 Flashes
Watchguard - burner failed to light,
exceeded maximum number of retries or
recycles
6 Flashes
Not used
7 Flashes
Primary or Secondary limit open or
watchguard mode - limit switch open
longer than 3 minutes
8 Flashes
Rollout switch open
9 Flashes
Pressure switch failed to close or opened
during heat demand
10 Flashes
Watchguard - Pressure switch opened 5
times during one heat demand
11 Flashes
Pressure switch stuck closed prior to
activation of combustion air inducer
12 Flashes
Flame sensed without gas valve energized
13 Flashes
Low line voltage
Summary of Contents for GUH95C
Page 3: ...507716 01 Page 3 of 58 Issue 1717 Figure 1 Parts Arrangement...
Page 22: ...507716 01 Page 22 of 58 Issue 1717 Figure 25 Figure 26...
Page 37: ...507716 01 Page 37 of 58 Issue 1717 Figure 59 Trap Drain Assembly Using 1 2 PVC or 3 4 PVC...
Page 56: ...507716 01 Page 56 of 58 Issue 1717 Start Up Performance Checklist...
