Carrier 48TJ016-028 Heating Service Analysis, MoistureMi$er TM Dehumidification, Problem Cause

Table 28 --Heating Service Analysis

PROBLEM		CAUSE
Burners Will Not	Misaligned spark	electrodes.
Ignite.
	No gas at main burners.
	Water in gas line.
	No power to furnace.
	No 24 v power supply to control circuit.
	Miswired or loose	connections.

Burned-out heat anticipator in thermostat.

Broken thermostat wires.

Inadequate Heating, Dirty air filter.

Gas input to unit too low.

REMEDY

Check flame ignition and sensor electrode positioning. Adjust as needed.

Check gas line for air; purge as necessary. After purging gas line of air, allow gas to dissipate for at least 5 min- utes before attempting to relight unit.

Check gas valve.

Drain water and install drip leg to trap water.

Check power supply, fuses, wiring, and circuit breaker. Check transformer. Transformers with internal overcur-

rent protection require a cool-down period before resetting. Check 24-v circuit breaker; reset if necessary.

Check all wiring and wire nut connections.

Replace thermostat.

Run continuity check. Replace wires if necessary.

Clean or replace filter as necessary.

Check gas pressure at manifold. Check gas meter for

input. If too low, increase manifold pressure or replace with correct orifices.

Unit undersized for application. Restricted airflow.

Blower speed too low.

Replace with proper unit or add additional unit.

Clean filter, replace filter, or remove any restrictions.

Install alternate motor, if applicable, or adjust pulley to increase fan speed.

	Limit switch cycles main burners.
	Too much	outdoor air.
Poor Flame	Incomplete	combustion (lack of combustion air)
Characteristics.	results in:

Aldehyde odors, CO, sooting flame, or floating flame.

Burners Will Not Turn Unit is locked into Heating mode for a one minute

Off.minimum.

Table 29 -- MoistureMi$er TM Dehumidification

PROBLEMCAUSE

Subcooler Will Not Energize No power to subcooler control transformer.

Check rotation of blower, thermostat heat anticipator set- tings, and temperature rise of unit. Adjust as needed.

Adjust minimum position.

Check economizer operation.

Check all screws around flue outlets and burner com- partment. Tighten as necessary.

Cracked heat exchanger.

Overtired unit --reduce input, change orifices, or adjust gas line or manifold pressure.

Check vent for restriction. Clean as necessary.

Check orifice to burner alignment.

Wait until mandatory one-minute time period has elapsed or cycle power to unit.

Subcooler Service Analysis

REMEDY

Check power source. Ensure all wire connections are tight.

No power from subcooler	control transformer to	1.	Fuse open; check			fuse. Ensure		continuity of wiring.
liquid line three-way valve.		2.	Subcooler	control		low-pressure		switch open.
			Cycle unit off and allow low-pressure switch
			to reset.	Replace		switch	if it will	not close.
		3.	Transformer		bad;	check	transformer.
Liquid line three-way valve	will not operate.	1.	Solenoid	coil	defective;		replace.
		2.	Solenoid valve stuck closed; replace.

Subcooler Will Not Deenergize	Liquid line three-way valve will not	close.
Low System Capacity	Low refrigerant charge or frosted	coil.

Valve is stuck open; replace.

1.Check charge amount. See system charging section.

2.Evaporator coil frosted; check and replace subcooler control low-pressure switch if necessary.

5O