Cruisair Not Working Right

[rff105]

We have had our coach for 4 years now and the 4 Cruisair units just are not able to keep up. The stateroom works OK and will get below 70. The 2 mid units don't work well and only get to about 75. And the front unit is worthless and is lucky if it can hold 80.

I have had both the compressors on the mid units replaced (they locked up 1 yr ago), they have checked my pressures and topped it off each year, and they have cleaned the exterior condensers every year.

I don't know if i am expecting to much out of the systems, but i would think Featherlite would have sized the units capacity to freeze you to an ice cube if you wanted. We went to the PSU/Alabama game last year and the coach would barely hold 84 even at night.

I ran all 4 units all day today in the garage. The garage was 79 degrees and the best the coach got according to by thermometer in the middle was 73 inside. If i can get it below 70 in the shade with high 70 outdoor temps, it does not stand a chance in the sun, at 80, with the lights and AV on, and 20 passengers going to a football game.

The service tech is coming to look at all the systems again tomorrow. Does anyone have any ideas what else we should be looking for? Or if this is the best i can expect what can i do to get more capacity up front? I have considered adding a roof unit if the power system could handle it.

[merle&louise]

Richard,

If you have 4 Cruise Airs they should cool the coach down when it is in a garage if they are working properly.

What is the difference in air temperature at the register where the cold air comes out and the air temperature at the return air grill? It should be about 15 degrees difference. If it is less maybe your evaporator coil is dirty. Is your return air filter dirty?

Sometimes the return air filter is difficult to find inside the coach. I have heard owners complain that the return air filter is behind the refrigerator! So I would say that it is very important to locate and clean all 4 return air filters.

If misery loves company, I am having AC issues as well. My evaporator fan shuts down after about 4 hours running. I changed a printed circuit board today and hopefully that will do the trick. I think that it may be a relay. Had the same problem with the bedroom AC last week! When it rains - it pours!

One other point worth noting - most AC systems are not able to get colder than a 20 degree difference between the ambient temp and the inside temperature of the coach. So if it is 100 degrees outside the best you are going to get is 80 degrees inside.

THIS DOES NOT APPLY IF YOU HAVE OTR !

[rff105]

I have been reading all the Cruisair posts i can find on the forum and my head is spinning. I will have my tech call AAP tomorrow if we don't find anything new.

i clean all for filters in the coach monthly looking for any performance gain i can get. Mid units are getting about a 5 degree difference and front is getting very little if any. I will get all the numbers across the units tomorrow.

[phorner]

.

I don't know if i am expecting to much out of the systems, but i would think Featherlite would have sized the units capacity to freeze you to an ice cube if you wanted. We went to the PSU/Alabama game last year and the coach would barely hold 84 even at night.

I ran all 4 units all day today in the garage. The garage was 79 degrees and the best the coach got according to by thermometer in the middle was 73 inside. If i can get it below 70 in the shade with high 70 outdoor temps, it does not stand a chance in the sun, at 80, with the lights and AV on, and 20 passengers going to a football game.

The service tech is coming to look at all the systems again tomorrow. Does anyone have any ideas what else we should be looking for? Or if this is the best i can expect what can i do to get more capacity up front? I have considered adding a roof unit if the power system could handle it.

Richard,

You're not asking too much of your CruiseAir units. We have been having temperatures here in South Florida in the low 90's and I can get by easily running 3 units during the day and 2 at night. We are comfortable with interior temperatures in the low 70's. Once the ambient temperature exceeds about 95 degrees, I need to run all 4 during the hottest part of the day.

We do try to make good use of our awnings and we have a sun screen on the windshield. Also, our Liberty is oriented almost perfectly north/south, so the sun doesn't really get a good chance to heat up the windshield area.

Good luck with your repairs...

[grantracy]

I was also having trouble with my aft cruiseair,I had repalced the entire condensing unit. It seems they are/were having trouble with a bypass valve in a lot of their units. Mine was replaced, then ultimately removed ( I believe this was recommended by Cruiseair) anyway you may want to have them check.

[Jon Wehrenberg]

Richard,

Tuga has offered some good advice that should help the techs diagnose your problems.

First, let me say I think it is unusual for all four units to fail to perform at the same time. Even if you do not have any refrigeration experience there are a few things you can do. First as Tuga suggests make sure the filters on the evaporator coils are clean. If you can get at the condenser unit coils clean them also. Then turn the units to the lowest temperature setting possible and then after they have run long enough (maybe 30 minutes) to have cooled down the discharge air path, measure the temperature at the point where the air blows into the coach. At the same time measure the temperature at the air return to the evaporator. As was pointed out the difference should be 15 degrees more or less. You can easily get these temperatures with an IR temperature gun.

Some POG members are getting as much as 20 degrees temperature difference and they have tweaked their units with the Freon charge to get the maximum performance.

You should almost never have to have anyone service or adjust the Freon charge if the units have been installed properly and are leak free. On my first coach my original units were 17 years old before I had to recharge the system and then if was because the Freon was leaking at a valve. These units are very sensitive to the amount of R-22 in the system (that is the Freon). There are theories galore about how to know it is right, but by measuring the temperature or the supply and return air and getting the maximum temperature spread you know when it is right.

Still puzzled as to why all four aren't performing. Maybe when you run the temperature test you will find that is not the case.

[jack14r]

The freon charge is critical,if you set the freon charge to the chart it will not be at the highest performance level.I use an infared gun and ty wrap the trigger on and aim it at the copper fitting on the suction side at the condenser,if they are charged correctly you will see a temperature of 35-42 degrees,this will take some time to tweak the freon to the lowest temperature there.There is another way and that is to measure the temperature of the evaporator from top to bottom in the center and it should be within 2 degrees and that will result in the greatest temperature difference.If your technician is not the patience type don't let him mess with your cruise airs.

[truk4u]

Richard,

All good advice, but since your in PA, a trip to AAP in VA may be your best bet. Your service guy really needs to understand Cruisairs and correct freon charge is a common problem as Jack pointed out.

[rff105]

Tech is not here yet but here are the reading i got this morning.

Garage Temp: 77.7
Motorhome Interior w/nothing running: 78.0

Turned on the units for about 15 mins each set to 55:
Front: Intake 78.0 Output 65.4 = 12.6 Diffrence
Mid-R: Intake 78.0 Output 69.2 = 8.8 Diffrence
Mid-L: Intake 78.2 Output 61.7 = 16.3 Diffrence
Rear: Intake 77.5 Output 58.9 = 18.6 Diffrence

[jack14r]

Work on the mid R and get the suction side as cold as possible and then measure the difference,let us know.

[rff105]

I talked with Johnny at AAP, he is out on medical leave but they gave me his cell phone. My tech is coming this afternoon and Johnny is going to talk him though the correct pressure setup. I'll let you know how it goes. They are only about 3.5 hours away but Johnny will not be back to work until mid Sept. I may take a trip down if i do not get it sorted out today, thanks for the refrence.

[GDeen]

Bill and Fred are also with AAP and know the cruiseair systems. I just went through a compressor change out in one of mine, and they were both very helpful. My guy didn't know cruiseairs, but we got the return line "beer cold" and all is well. I am seeing about an 18 deg differential on the unit which is good.

[Sawbonz]

Hijack alert!

We just spent our first weekend in ours since picking it up. The rear CruiseAir seemed to need to be set several degrees lower than the other units, but blew cold at that point. I didn't measure any temps, and just now emailed Troy to see if he can tell me where the returns are so that I can clean filters.

Is it too much to expect to keep all units on the same temp setting?

Is it unusual to have the rear units not cool down the bedroom enough when the door to the salon is closed?

[Jon Wehrenberg]

This is personal experience only so take it for what it is worth.

Based on where my units are I set each for slightly different temps so the interior of the coach feels at a uniform temperature. That may be because the front with its abundance of glass needs a different setting than a midship unit. It may also be because the relationship of the return air to the supply air is such that the SMX control needs a different setting because on one some of the chilled air is being returned and on another the return air is less affected by the supply air.

Also, keep in mind our SMX units can be calibrated and it might be each has been calibrated slightly differently.

Going further without looking at the data such as the temperature spread between supply and retunr air it is unknown if the units are working to the same level of efficiency, and if not that would also impact their set point to maintain comfortable temps.

As to the question about the aft unit cooling the bedroom with the door closed you don't mention if the engine has been running or if there are any other factors which will impact that unit's ability to cool.

If you measure the temperature spread on all your units you answer in part a lot of what you are quesitoning. You know immediately if your units are working properly. Then since the thermostat sensors are likely in the return air flow you can measure the temperature at which point the units cycle, compare their respective set points and temperature readings and you will know if the calibration is correct. If not recalibrate the temperatures. Then you have to look at variables such is sun pouring in through the front windows? Has the engine been running, is supply air being drawn back through the return? Are the filters clean?

If you use an IR gun, then as Jack suggests you can get a sense of the operation of the units by getting the suction line temps (the line that is at the condenser and is sweating). If they are wildly variable you can probably assume you need to adjust the R-22 Freon charge to maximize the efficiency.

There are so many variables and data reference points the best place to start is by making sure the basics are known and are correct. The temperature may be 75 degrees, but the Cruise Air control might be seeing that as 70 degrees and obviously that shuts the unit down prematurely so pull out the book and the IR gun and start with some good temperature checks and calibrations if required. Unless you have done the calibrations you are trusting they are correct.

[Gary Carmichael]

Who is AAP and where in VA are they located?

[Jon Wehrenberg]

They make the Cruise Airs. Now owned by Dometic I believe. I think they are from Virginia. You should have their contact info in your owner's manual.

I assume you are going to Austin. You will get a personal delivery of your stands.

[Sawbonz]

This is personal experience only so take it for what it is worth.

Based on where my units are I set each for slightly different temps so the interior of the coach feels at a uniform temperature. That may be because the front with its abundance of glass needs a different setting than a midship unit. It may also be because the relationship of the return air to the supply air is such that the SMX control needs a different setting because on one some of the chilled air is being returned and on another the return air is less affected by the supply air.

Also, keep in mind our SMX units can be calibrated and it might be each has been calibrated slightly differently.

Going further without looking at the data such as the temperature spread between supply and retunr air it is unknown if the units are working to the same level of efficiency, and if not that would also impact their set point to maintain comfortable temps.

As to the question about the aft unit cooling the bedroom with the door closed you don't mention if the engine has been running or if there are any other factors which will impact that unit's ability to cool.

If you measure the temperature spread on all your units you answer in part a lot of what you are quesitoning. You know immediately if your units are working properly. Then since the thermostat sensors are likely in the return air flow you can measure the temperature at which point the units cycle, compare their respective set points and temperature readings and you will know if the calibration is correct. If not recalibrate the temperatures. Then you have to look at variables such is sun pouring in through the front windows? Has the engine been running, is supply air being drawn back through the return? Are the filters clean?

If you use an IR gun, then as Jack suggests you can get a sense of the operation of the units by getting the suction line temps (the line that is at the condenser and is sweating). If they are wildly variable you can probably assume you need to adjust the R-22 Freon charge to maximize the efficiency.

There are so many variables and data reference points the best place to start is by making sure the basics are known and are correct. The temperature may be 75 degrees, but the Cruise Air control might be seeing that as 70 degrees and obviously that shuts the unit down prematurely so pull out the book and the IR gun and start with some good temperature checks and calibrations if required. Unless you have done the calibrations you are trusting they are correct.

That helps a lot. The bus has been parked for a couple weeks, so no engine heat. We had the doors closed because of the kids, but at 72 it wasn't cool enough, even though it never shut off. At 69 it was better, but that seemed really low. When we picked it up the tech calibrated the units, so it SHOULD be right after this short of a time.

I need to find where the filters are, as we missed that during the demo. I have an IR gun, and need to put it to work. As to those lines, perhaps someone will show me in Austin.

[jack14r]

Karl,The Cruise air manual it has the info on how to adjust the controls on the SMX controller,also look for louvred panels usually below the cruise air vents,these are held in place by 4 of the cabinet latches and they pull straight out and you will find the filter behind there just in front of the evaporator.

[Sawbonz]

Great, thanks Jack. I wish I could tag this post for later quick reference, since I can't back to the rig before we leave for Austin.

[garyde]

The filters on my Coach are;
1.Bedrom; back closet, port side, behind white panel.
2.mid-coach; Pantry clset; remove bottom shelf
3. Galley;wall vents by dining seat; grill vent pulls out

Once you remove the panels, shelf, or grill, you have to kind of reach in and fumble around for the filter. Its a washable filter.

The front a/c ; just remove the bottom vent cover at the front step a/c unit.