Community Forums

sallylillian · 03-25-2014, 01:41 AM

I was unhappy with my OTR AC, but it had been poor since I purchased the coach 3 years ago so I just assumed that was the way things were. Anyway this last service I asked the techs to check and recharge the AC. This is their report:-
Air Conditioning recharge-not completed-CRTS confirmed low level of R134a refridgerant in system,have traced leak to swaged connection on hose next to test point at rear-faulty hose replaced,system now recharged to correct
pressures-Additional fault now identified as defective low/high pressure binary switch controlling A/C fan.New switch
ordered.
Is the AC fan a different one from the main engine radiator one? It has been explained that the original switch is no longer available and that the replacement will allow the AC fan to run permanently if the AC is selected on the dash.
I would appreciate any feed back on this before the switch is replaced.

laj · 03-25-2014, 02:20 AM

i will try to explain this as short as i can. replace the hi/lo pressure switch, it has to be working correctly for your a/c to work right. when your a/c is on the system creates high pressure, the switch sends a signal to the cooling fan, all automatic, the fan comes on and cools the freon back down. when it gets to the low pressure it shuts the fan off. this will cycle as the pressure goes up and down. when you get to the low pressure the switch shuts the fan off.all automatic. all this switch is, it has 2 wires going to the fan controller. . its not an actual switch as you would think of as a switch you can manually turn on and off at will. its part of the a/c system.
hope this helps. someone will be along that can explain it better.lots of good people on here. jmho

laj · 03-25-2014, 02:26 AM

i believe all of them run the cooling fan continuously when the dash a/c is selected.

deandec · 03-25-2014, 10:15 AM

My old rig has two condenser fans mounted at the passenger side rear for the OTR system. They are different than the side mounted engine fan on the driver rear side.

The switch description is above my pay grade.

smlranger · 03-25-2014, 05:42 PM

My condenser fan is a separate fan assembly mounted in the middle bay that has the LP tank on the passenger side and the fan assembly on the driver's side. It cycles on/off when I use the automotive AC.

Strangely, I may have a similar leak. The area around my low and high pressure service fittings in the engine bay was oily and when I removed the high pressure cap, there was red compressor oil bubbling in the fitting. I figured if it was leaking compressor oil all the freon must be gone.

I have an appointment to have it checked.

However, this past weekend after changing fuel filters and hydraulic fluid filter, I ran the engine to check everything. I switched on the dash AC and it blew really cold air so go figure.

sallylillian · 03-26-2014, 01:15 AM

Thanks all for the feedback. After a suggestion on Yahoo groups I contacted CC about the issue. Greg was very helpful, they have a trinary switch in stock so its ordered and on its way to me! here is Gregs explanation of installing the alternate binary switch.
If the Binary switch was installed and allowed the fan to run all the time when AXC was selected, then your fuel mileage would suffer some and the fan would receive excess usage that could cause premature failure over a long period of time. The fan controller on the coach is designed to only operate the fan at high speed, approximately 3000 rpm, when engine temp is at 205 degrees plus or when the AC high pressure is 212 lbs or above.
This helps limit its usage, wear & tear, and help keep fuel mileage up, could loose as much as 1.5 MPG if fan is run at high speed all the time.

Additional info, your coach should use 9.75 oz of Pag oil and approximately
4.5 lbs of R-134 refrigerant (Min 4.0 lbs & Max 5.0 lbs).

Medico · 03-26-2014, 06:26 AM

Thanks for sharing Greg's answer.

sallylillian · 04-02-2014, 09:35 AM

I have had an interesting couple of weeks with the OTR AC on my 2008 Allure. She went in for an annual service and MOT (UK government vehicle examination) and having been somewhat perplexed for the last 3 years with the quality of OTR AC I asked them to get a HVAC guy in to recharge the gas.
Well that was just the beginning!
They go to recharge the gas at the engine bay points and are not happy as they see a leak in the pipe at the swage joint. So the system is evacuated and vacuumed and a new pipe made up to replace. Now onwards with the recharge.
That gets done but the tech is not happy with the operation, with pressure and temp climbing and the cooling fan has not going into fast revs. He is led to the trinary pressure switch and by a process of jumping leads determines that the switch must be faulty as he can get the fan operating.
Without consulting me they go off and try to source a replacement, eventually routing to Evans Tempcon in the US who state that the trinary switch is no longer available from them, only a binary which they order. When I find out I make some postings on here and iRV2 and get feedback that these trinary switches are out there, contact CC which I did, and $118 plus delivery later it’s on its way.

Switch gets here to the UK and Tech comes to my barn to fit it. No change. After a lot more trouble shooting he decides that the thermostat is wired incorrectly and changes that to bypass the pressure switch and now we have the system working as it should. Pressure and temp rising and then falling as fan cuts in. But I am puzzled why would CC have designed a system that fundamentally did not work. I ask the tech if any of the wires to the switch could just be incorrectly wired. Without a schematic he was stumped for an answer.
So I emailed Gregg again at CC and he sent over a schematic which is not in my Chassis pack. It shows the switch wire colours to the tag numbers of the CC loom, and I go to the coach to check and sure enough 2 wires are transposed.

So this coach came out of the factory wired wrong, the OTR AC can never have worked properly or efficiently and the original owner obviously did not pick this up.” Pete if your reading this let me have your opinion on that part”
So to any of you who are unhappy with your OTR AC, and I know there are some as its those sort of comments that led me to believe that my AC was just how things were…not like my Audi A7 that’s for sure, so get the wiring diagram from CC and check your pressure switch, it’s easy. Out the gen slide and it’s up under passenger side.
You may find you own better OTR AC than you thought!!