Nibe Climate Master RGED Series, Installation Instructions Manual

Page: 68 / 160

68
N. DIAGNOSTICS
Alarm Codes - Heating Only
CODE MAIN LIMIT OPEN
22
DESCRIPTION: The furnace will not operate in gas heat mode.
CAUSE:
1. No airflow or dead blower
2. Insufficient airflow
3. Faulty limit control
4. Loose or faulty wiring.
5. Incorrect blower tap
6. Furnace input is too high.
SOLUTION:
1. Check for proper blower operation. If a blower motor fault
has occurred fault code “61” should also be present. Check
the wiring to the motor then the motor.
2. Check filters and ductwork. Determine static pressure and
confirm it is not above published values found in the
Checking and Adjusting Airflow section.
3. Replace the limit control
4. Check wiring and connections.
5. Confirm proper blower speed taps for high and low-fire.
6. Insure properly sized burner orifices are installed. Check
manifold pressure at high and low-fire and compare to val-
ues found in Measuring and Adjusting Manifold Gas Pres-
sures section. Check rate and compare to nameplate input,
high and low-fire. Adjust as necessary.
33
MRLC (Manual Reset Limit Control) OPEN
DESCRIPTION:
The MRLC is also known as the rollout limit.
There are two rollout limits on (-)GEC gas units. When one or
more of these limits open, they must be manually reset to the
closed position. This fault can occur when burner flames are
not directed down the center of the burner tube and roll out into
the burner assembly. This fault indicates a serious problem that
must be repaired before furnace operation can continue.
CAUSE:
1. Faulty limit.
2. Loose or faulty wiring.
3. Damaged heat exchanger
4. Insufficient combustion air or blocked flue pipe.
5. Overfired condition.
6. Air leak between burner and blower compartment.
SOLUTION:
1. Replace limit if limit will not reset. Observe flame pattern for
normal operation after limit has been replaced.
2. Check wiring and connections. Replace and/or repair as nec-
essary
Fault Codes with Descriptions and Solutions: