Aquacal HP7 Manuale Utente

Defrost Sensor Open  Cut or loose sensor wiring  

Water Temperature 
Sensor Open 

Cut or loose sensor wiring  

Defrost sensor 
shorted 

Short circuit in defrost sensor wiring or defective sensor. 

Water temperature 
sensor shorted 

Short circuit in water sensor wiring or defective sensor. 

Refrigerant system 
low pressure switch 
open  

System refrigerant charge low or defective low-pressure switch.  

Refrigerant system 
high pressure switch 
open 

Low water flow, defective high-pressure switch or wiring. 

[FLO]   Low or no water 

flow detected 

Circulating pump off, isolation valves set improperly, defective 
water pressure switch.  

Heater in defrost 
mode  

Normal function in lower air temperatures. Fan continues to run 
and compressor is off. Compressor will restart when air coil 
temperature reaches 38

°F or above.   

Control system error  Control may need reset. Disconnect then reconnect power to reset 

control if error continues replace control board. 

 

 

 

The Microprocessor Control monitors the heater’s air-coil temperature, minimizing air-coil  
freeze-up during cooler weather conditions. Should the control sense air-coil temperatures 
conducive to making ice, the heater’s compressor operation is interrupted while the fan is 
allowed to continue in operation. With the compressor off,  the air coil begins to warm to the 
surrounding air temperature. As air-coil temperatures rise above approximately 38

° F,  the 

compressor is restarted and heating resumes. In the event air temperatures remain below 
approximately 38

° F,  the compressor will remain off until the air temperature rises above 

approximately 38

° F.  Heating of water will not be taking place as long as the compressor 

remains off.   

 

17