air conditioner

[Mike in S Fla]

Got a cruisair question coppressor trys to start but immedidly stops gauge shows about 50psi on the cold side, is that how a bad capacitator acts

 

[Boatsb]

Whats the amp draw?

It will pop a breaker if its a bad compressor.

 

[Mike in S Fla]

not popping the breaker Scott, repeadily trys to start about every 5 seconds sound like coppresors runs for about half a second then shuts off and retrys about 5 seconds later thanks for the reply

 

[Boatsb]

Could be low Freon, bad sensor or other issues.

What doe's the pressure do when it tries to start?

Low pressure should probably be 60 to 70 psi depending on temp when running. If its 50 psi on the low side before starting you probably are low on gas and tripping the low pressure safety switch.

 

[Mike in S Fla]

Thats what i thought, low pressure, i have a tank and gauges on it now for the breif time it starts pressur reading starts to drop try to add fron but wont take it

 

[wpc691]

Raw water line maybe blocked?

 

[johnjen50]

A friend of mine had this happen to him last summer and it ended up being low freon, or 134A whatever they put in now.

 

[BOATER BOB]

Replace starting capacitor.
Bob

 

[Pete]

Sounds like a three knob control unit behavior, so I will assume this. If so, sounds like two problems, first the short cycling is most likely the "run" capacitor, the silver metal cased one in the control box on the compressor unit. With the breaker off, take a look at the top of this capacitor where the terminals are located and see if the top of the can is still flat or bulging upward. If bulging replace it. The compressor starting initially indicates to me that the start capacitor and potential relay are functioning correctly and the problem starts when the run capacitor fails to provide the required phase shift to keep the compressor motor running.

Regardless of the status of the run capacitor, you are low on refrigerant as mentioned already, and need to get up in the range of 60 or 70 lbs on the low side when not running. Once there use some gauges and a charging chart to get the setting correct when operating.

Pete

 

[Mike in S Fla]

Thanks guys for the advice Ill check all the suggestions when im back on the boat next weekend


thanks

 

[Reefgeorge]

Whats the amp draw during the brief on period, this behavior can be a locked compressor. Most compressors have a LRA rating on the can which is the amp draw during this condition. The compressor tries to start and then overheats. The temp sensor on the side of the can then shuts the power off to the compressor. When the sensor cools down it tries again. A hard start kit might buy you some time and rapping the can during start up can sometimes break the thing loose for a few start ups but its toast in short order.

As stated above it can be the capacitors as well. The start, run or the relay that does the switching function during the start up sequence.

It can also be low refrigerant. When the system is idle the pressures are equalized across the metering device so that the low and high side are equal and at the correct pressure for the ambient condition. At start up, the low side starts to drop and the high side starts to rise, If your low on gas then the low side switch shuts the system down as the suction side passes through around 30 PSI. This takes about 10 seconds or so and should show a fault code on a digital display set up.

A malfunctioning heat exchanger will do the same thing. The high side goes above the limit switch and shuts down. Again a digital display will show a fault.

Don't add gas unless you confirm a low charge condition or you might have new problems to deal with.

George