New Winnie Owner... Couple of Questions about AC Cooling

bnd10706 · 09-23-2022, 11:30 AM

We just purchased a 2008 Sightseer 35j. We have only owned a TT before this, and one of the things about my TT was that it would blow FREEZING cold air from the AC.

With this Sightseer while it feels like there is cool air coming out, it is still 80 degrees in the rig.

yesterday was our first time driving it and I ran the generator while driving. The cab AC was barely cold, and both ACs running was moderately cool, the temperature gauge I had on the dinette never dropped below 79.

In the Florida heat it still felt hot. Is there anything I should start with to try to get my ACs able to keep the Rig cool?

**creativepart** · 09-23-2022, 02:00 PM

You didn’t say how hot it was outside. If it was high 90’s that might be ok, but 80 should be cooler than that

Get an instant read thermometer and measure the air temps coming out of your ducts. The air should be good and cold. If it’s not you have a problem with your A/C unit.

bnd10706 · 09-23-2022, 02:51 PM

Quote:

Originally Posted by creativepart

You didn’t say how hot it was outside. If it was high 90’s that might be ok, but 80 should be cooler than that

Get an instant read thermometer and measure the air temps coming out of your ducts. The air should be good and cold. If it’s not you have a problem with your A/C unit.

Sorry yes, it was low 90s yesterday. But i dont think thats a good reason. The back AC unit is SUPER cold. the air coming out of the front until is moderatly cold. Even today, its 87 out and over cast and im plugged into shore power and its struggling to bring the temp down to 80.

I just installed thermal covers on the windows etc. so its not that. I dont know if the AC just needs a recharge of coolant or a full replacement.

**creativepart** · 09-23-2022, 03:43 PM

RV A/Cs don’t have refrigerant ports. So the only way to add refrigerant is if you find an A/C Tech that’s a) willing to get up on the roof and b) willing to add a new fill port to the tubing. Some folks have been lucky enough to find someone do this. Other times some owners have removed the unit from the roof and taken it to shop for this work to be done.

However, normally the entire A/C unit is simply replaced.

IOS 3 · 09-23-2022, 05:10 PM

Are you sure both compressors are running at the same? If the rear unit is cooling, and the front unit is running fan only, you might get the conditions you describe. I would do what has been suggested and measure your vent temperatures and verify you are getting at least a 20-degree differential from ambient. You can by an inexpensive probe thermometer at an auto parts store if nothing else.

**creativepart** · 09-23-2022, 06:03 PM

A good question to ask is does your RV have 50-amp power and if so… are you plugged in to 50-amp service?

Because, if you have a 30-amp RV OR if you have a 50-amp RV and are plugged into a 30-amp power pedestal then you cannot run both A/Cs at the same time in full cooling mode.

bnd10706 · 09-24-2022, 05:55 AM

The RV is 30amp. It is hooked up to shore power at my house and is drawing 23 amps with both ACs on.

Yes both compressors are running. I can hear them turn on and I have played around with them. Turning one on then another.

While both are blowing “cold” the back one blows really cold and the front one blows cool.

It does not seem to be able to keep the front cool at all. Just a bit worrisome.

**creativepart** · 09-24-2022, 08:57 AM

Quote:

Originally Posted by bnd10706

The RV is 30amp. It is hooked up to shore power at my house and is drawing 23 amps with both ACs on.

There is your answer. On 30-amp you will not get both compressors running continually. Both fans can start up, but start up for both compressors will draw too much power. The same is true if both A/Cs are on and you run the microwave.

This would indicate that the RV is operating normally and you don’t have any problem with your A/C units.

There are things you can do to help with this issue but all of them require modifications to your RV.

John Mo · 09-29-2022, 08:15 AM

Hi, I have a 30-amp 2009 35J.

First, it is not true that you can't run both units on shore power at the same time. Both compressors will run at the same time. You won't run much else at the same time except lights and TVs. The power management system does a decent job keeping both airs going.

You probably just need to replace that front unit if it's not blowing really cold air. I've replaced both air conditioners on my 35J. I think the front one made it until about 2 years ago. The rear was replaced several years ago.

One thing that helps with these 30-amp units is to add a soft start capacitor, so you might want to look into that if you have good, cold output from the air conditioners, but still have some concerns about getting both up and running at the same time.

Morich · 09-29-2022, 09:01 AM

Since we don't really do a good job of judging temps, I would really start with getting firm numbers fo the temp of the air going in and then what is comming out. That is the only real way to say if it is working right as there are some many other factors involved. Just the difference in the two rooms is obvious. One may have lots of windows and hot equipment than the other?? The one in front may be fighting to cool two bodies and the entry door, plus things like the hot converter and TV, so it may just have a tougher job. Cooking and washing dishes may skew the results, so real numbers are needed.
But a check of the cleaning of filters and air vents is an easy start.
The one next to the stove may have filters that are gunked up with cooking grease!

cruizerEd · 09-30-2022, 06:36 AM

Really dig into the front units function before replacing it. First off run each unit by itself and feel (or better yet measure) the air temp in and out. Also verify the current draw on each units independently after about 5 minutes of running.

Check that the evaporator and condensing coils are clean and that the filters are in good shape. If the high pressure line (the small one) is hot and the low pressure side is cold you have some compressor function but it may not be enough. Also make sure the compressor is running the whole time not just starting this is true for the condenser fan (the one the blows the outside air) as well.

Make sure that the return air flow is not mixing with the cooled airflow and that there is no significant leakage of outside air into the return or from the cooling side.