Sanyo CHDXR09663, CHDX09663, CHDX07263 H06 Alarm Alarm code, Which may damage the compressor

4. W-2WAY ECO-i Alarm Codes

W-2WAY ECO-i SYSTEM Trouble Diagnosis

H06 Alarm

Alarm code	H06
Alarm meaning	Low-pressure switch activated
Alarm conditions	A report occurs during A/C operation when the low-pressure sensor installed at constant
	low-pressure parts detects a pressure of 7.3 psi or less continuously for 2 minutes,
	or an instantaneous pressure of 2.9 psi or less. (These values represent abnormal low pressure
	which may damage the compressor.)
	However, the alarm does not actually occur the first 2 times that the above operation takes place.
	At these times, the outdoor unit is stopped and the conditions are monitored. The alarm occurs
	when the above operation occurs for the fifth time. The first 4 times before the alarm occurs are
	called “pre-trip.” After pre-trip occurs, if the low-pressure sensor detects a pressure of 21.8 psi or
	more for 3 minutes of continuous operation, the pre-trip count is reset to 0.
	If the low-pressure sensor detects a pressure of 23.2 psi or less continuously for 30 minutes
	when the compressor is stopped, an alarm occurs immediately (no pre-trip).
Probable cause	The A/C unit low pressure has dropped to a level that does not occur under ordinary conditions.
	(1) The absolute amount of gas in the system is too low (as a result of insufficient refrigerant
	charge or leak).
	(2) The refrigerant has accumulated in the circuit and has not returned to the compressor.
	Refrigerant has accumulated in a location of one-way flow and cannot escape.
	High-pressure level is low, resulting in poor flow of refrigerant in the circuit. (A lower high-
	pressure level results in a smaller difference between low pressure and high pressure, that
	may be insufficient to cause refrigerant flow.)
	(3) The refrigerant circuit has become closed, and refrigerant has not returned to the
	compressor. In some cases when moisture enters the refrigerant circuit, it can freeze at the
	low-pressure locations and the resulting ice can block the circuit.
	If the alarm occurs when there is sufficient refrigerant in the system ((1) and (3)), liquid
	refrigerant has definitely accumulated somewhere in the system. Liquid refrigerant generally
	accumulates in high-pressure locations. In this case the high pressure gradually increases
	(however it may not increase if the location where the liquid accumulates is sufficiently
	large). Depending on the refrigerant saturation temperature, it may also accumulate in low
	pressure locations. In this case the high pressure is unlikely to increase.
Check	(1) Check that the service valve is open.
	(2) Check that none of the valves (solenoid valves, mechanical valves) in the main refrigerant
	circuit is closed due to an operation failure.
	(3) Check that there is no possibility of foreign objects or water having entered the refrigerant
	circuit.
	(4) Check that valve leakage at a stopped sub unit has not resulted in accumulation of
	refrigerant at that sub unit.
	(5) Check that no refrigerant leakage has occurred.
Correction	(1) If there was a valve operation failure, in general it is necessary to replace the valve.
	(2) If a foreign object or moisture has entered the circuit, install a strainer or dry core (depending
	on the degree of the problem).
	(3) If refrigerant has leaked into stopped sub units, it is likely that valve leakage has occurred.
	The valve must be replaced.
Example
Notes

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