SMX Controls - Cruisair

[truk4u]

Just curious... Do you have your SMX control for the A/C's fan set to run continuously or shut off when reaching the set temperature? Wondering what is better for the cruisair's, turning on/off or continuous operation.

The manual gives the option of continuous or intermittent fan... It notes the ability of the SMX controls to operate continuously at very low fan speeds without being concerned about equipment stress.

[Jon Wehrenberg]

Right now ours is set to cycle on and off. But I have to say that there may be advantages to continuous running, such as tending to dry the evaporator coil instead of shutting down when it has condensate, possibly creating mold.

Good question.

[HarborBus]

I had ours changed to cycle on and off. But in retrospect, like Jon says, there are pros and cons as to which way to set them. Time will tell.

[Steve Bennett]

We always run the fan continuously when the A/C is operating. I do not think there would be any additional wear on the components, and there may even be less as the fan is not starting and stopping continuously. Also, as John indicated it will help to keep the evaporator dry which will eliminate the problems with excessive moisture, mildew etc. The other benefit is that it will keep the temperatures in the coach more consistent as it is constantly circulating the air. An added bonus is that many coaches use the area behind the refrigerator as a large plenum for the evaporator to receive its' return air. This air will be heated by the refrigerator, and may take longer to cool off if it has not been circulated. Same thing in the front overhead, and rear cap if the coach is sitting in the hot sun. I even operate our dash A/C in the bus, and our passenger cars for a few minutes without the compressor going to dry off the evaporator prior to shutting down.

[Jerry Winchester]

We run our with the fan in "Auto" so it adjusts to the amount of cooling needed and stirs the air all the time. I find the controls to be very responsive as the front Cruisair really cranks up on a hot day when you open the door very long.

[GDeen]

The cruiseairs are pretty versatile little systems particularly coupled with the SMXII controllers. Had a malfunction with the SMX on the last trip and had to read the manual. Lots of features and customization options. I have mine set with the fan on all the time and speed set to auto.

[phorner]

Ours are set to Auto. You can program how the fan reacts to temperature change when in Auto Mode, but I haven't tinkered with ours.

I'm happy with the way they work as is...

[tdelorme]

One of our Cruisairs does a strange thing. No matter the setting, if the unit is running, every ten minutes or so it will cycle down to the low fan speed for 8 or 10 seconds and then resume running normally. It cools great and has never given me any trouble. I talked to Johnnie at AAP and he said not to worry about it, that the SMX was programed to do this and it could not be reprogramed to run like the other two in the coach. Of the three we have, this one seems to cool just a little better than the others, but they all do a good job. I just set um on Auto and they do their own thing. I love Cruisairs and the service at AAP is first class.

[TG Transport]

I've got to put in a plug for Johnny at AAP and Marathon for the help with another diagnosis.

I have 4 RTUs and 3 SMX systems in my bus. The front SMX display and controls stopped working several weeks ago even though the controller would still activate the AC unit. I suspect that was just the last mode it was in. I switched the key pad with another in the coach so I knew i knew the problem was in the control module. Both AAP and Marathon initially suggested that temperature sensor had gone bad but a few tests with phone cables and double-female connectors ruled that out. Long story, short version - Johnny sent me just a replacement circuit board to keep costs down and save me from having to re-feed wire.

Except for 60 uncomfortable minutes squeezed into the back bedroom closet, the repair was a DIY success despite moments of self-doubt, fear of electrical fires, and visions of taking it into Marathon in humiliating defeat.

[Jerry Winchester]

I have been making the transition from Cruisair to some manner of Airxcel roof AC which actually uses SMX controls. Go figure. But I don't think the ultra low setting on this new unit is as slow as the Cruisair. Now it is also a little different with the ducted unit since the air seems to just "appear" as opposed to blowing hard out the registers, but it's cold and that's what counts.