AC behavior during hot weather

[DaleM]

My wife and I have noticed a behavior with our AC system that I'm not sure where to start looking. Nothing on here came up because I wasn't sure how to clearly search for this situation. The weather was VERY hot this past weekend. The AC kept the cabin very cool so it seems like the performance of it from that point of view is fine. What we notice though is the thermostat will reach the set point of say 65* and turn off. Then in a few minutes (3 or less), you'll hear a click, and then the system turns on again blowing cold air.

It doesn't feel like the cabin is heating up that quickly to warrant the system to kick on. I have cleaned the filter. There's no ice build up. Could this be something with a set point on the thermostat that I messed up when I changed the fan from continuous to intermittent?

Open for suggestions!

 

[CliffA]

My wife and I have noticed a behavior with our AC system that I'm not sure where to start looking. Nothing on here came up because I wasn't sure how to clearly search for this situation. The weather was VERY hot this past weekend. The AC kept the cabin very cool so it seems like the performance of it from that point of view is fine. What we notice though is the thermostat will reach the set point of say 65* and turn off. Then in a few minutes (3 or less), you'll hear a click, and then the system turns on again blowing cold air.

It doesn't feel like the cabin is heating up that quickly to warrant the system to kick on. I have cleaned filter. There's no ice build up. Could this be something with a set point on the thermostat that I messed up when I changed the fan from continuous to intermittent?

Open for suggestions!

yes.....I tried to change my fan to only come on 'as needed' but I was never happy with the performance of the AC.....it cycled frequently and did not do a good job of maintaining the temp in the cabin at a constant level...I relocated the thermistor to be exposed to the cabin air......I also tried to set the sensitivity of the thermistor and the cycle time.....I played with the AC system for a couple days but eventually switched it back to the OEM set up which does a better job.....without the fan blowing continuously to circulate the cooler air the temp in the cabin can heat up very quickly on a hot summer day thus causing the unit to cycle back on sooner....

cliff

 

[Jaybeaux]

Dale,

Let me preface this by saying I'm no AC expert by any means. I have observed some "funny" behaviors with the thermostats. One night 73 as a setpoint is fine, the next it is too hot! Don't get me started about running the heat!

My theory is that the living quarters of the boat are not necessarily insulated like your home. I believe that that heat is radiating through the side of the boat thus tricking the thermostat into calling for cool.

I've learned to "ignore" these little eccentricities. If warm, make it cooler; if cold, make it warmer. You hit the nail on the head that your system (the compressor/condenser/evaporator) is working normally. Kick back and relax. I have a brand new AC and thermostat in my salon.

Jaybeaux

 

[DaleM]

Thank you both for your replies. I am going to reprogram for the really hot months to have the fan run constantly and see what that does. For the beginning and the end of the season, cycling seems fine.

 

[bmac]

I believe what you are seeing is the unit going into defrost mode to ensure that your coils don't freeze over.

 

[NotHerDecision]

Maybe check the temperature probe in front of the coils. It has a little clip that it goes in to measure the temperature of the return air. If it is touching the coils it can get a reading that is too cold. Then as soon as the unit turns off it reads high and turns on the system starting the issue of short cycling. So make sure it is placed where it should be and then...

Make sure the filter before your coils is clean. Once you clean that the actual coils also require a little cleaning. You can clean them with ac coil cleaner which is a aerosol cleaner that comes in a can at Home Depot for 5 bucks, then rinse the coils with plain water, I put water in a small garden sprayer and carefully rinse the coils.

I'll bet it works significantly better once you do this and it can all be done in 10 minutes.

Josh
Sent from my iPhone using Tapatalk

 

[sbw1]

I believe what you are seeing is the unit going into defrost mode to ensure that your coils don't freeze over.

That is my guess as well. And, it is a guess. Notice this especially on hot, humid days. Leaving fan on constant makes it better.

 

[DaleM]

I'll check the thermister and head to HD to get the cleaner. Thanks for the suggestions.

 

[Crushin It]

Dale, I noticed mine doing the same thing. It would cycle off and within 30 seconds back on. I thought the same thing, how could the interior be warming so fast? Hopefully this is normal...

 

[The Bill Collector]

I leave the fan blowing on low always....

 

[LG111]

The thermostat is near the screen on the unit. It's hooked to a wire lead. You can move it to another location where the air temp is different.
In the winter I move mine to the OEM location. In the summer I move it near the air intake grill under my seat. Seems to have a better balance of temp variance.

 

[DaleM]

I'll give all these suggestions a try. I'd be more concerned if the unit was developing ice or not cooling at all. Seems like this is more related to the sensor, air circulation, or just because it's friggin' hot and humid. I'll take hot and humid over anything Nov-Mar can deliver!