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Wiring in Trinary Switch

16K views 6 replies 3 participants last post by  MissionCritical 
#1 ·
I've tried to search for an answer to this, but can't find one. I have a Vintage Air system, and was trying to determine where I was going to put all of my A/C components. My system comes with a trinary switch that goes into the drier. The Vintage Air instructions can be a little vague at times, and I'm stuck trying to figure out how to wire in my trinary switch with my electric fans.

One thing I am not 100% sure on is the purpose of the trinary switch. I assume it protects from an over and under-pressure situation, but I don't know what the other purpose is.

My current BeCool fan setup is a dual SPAL configuration. Each fan is turned on by a relay that gets triggered from a grounding-type temperature sensor. I also have a BeCool relay that can turn on the fans when the A/C is turned on. Its this relay and the relationship to the trinary switch that I don't understand:

My 'turn on the fans when the A/C is turned on' relay basically justs gets a signal from the clutch wire (blue wire), and then grounds the temperature sensor for the fans, effectively turning them on. This relay does not have any power run into it, but rather just triggers a ground to turn on the fans.

The Vintage Air relay wiring 'documentation' that comes with the trinary switch (they don't provide the relay) is here:

http://www.vintageair.com/Downloads...-VUS Trinary Safety Switch Wiring Diagram.pdf

I don't understand what the relay in this drawing is doing, and if I need it at all. I 'assume' that what is happening is its turning on the fans when the A/C is turned on. If that is the case, then I would just run my blue wire from my existing relay into the blue wire on the trinary switch, right ?

What I'm lacking is knowing what the trinary switch is wanting to see and what the other function is that it performs.

Thanks

-Kevin
 
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#2 ·
the trinary switch is for low pressure. when it is too low on freon it doesnt allow power to go to compressor. since you got a relay allready from your electric fans. terminal 86 will have 2 wires. 1 from the trinary switch and 1 from your coolant temp sensor. both will ground relay when compressor is on or engine is hot enough. that way compressor on fan on if comp off or cycling but engine hot fans will still stay on. hope i explained it to you somewhat :D
 
#3 ·
Yes, thank you. I 'think' I may now have it. I looked at my existing fan relays and they have the 86 terminal going to the temperature sensor which turns on the fans. So the way I understand it, I can run the wire from the trinary switch and splice it into these wire running from my fan relays. This would eliminate my other relay that I was going to use to turn my fans on when my A/C was turned on, since the trinary switch is going to send a grounding signal to my fan relays.

-Kevin
 
#4 ·
The trinary switch does, as you stated, high pressure protection, low pressure protection(protects from refrigerant loss) and the third function is for fan override. Your fans would only be kicked on when the head pressure reached the preset pressure. The third function is not necessary if you want to run the fans whenever your air conditioner is running.
Gary
 
#5 ·
Now I'm getting confused again. The 3rd function, the fan override: does the trinary switch only turn the fans on when a certain condition is met ? I was assuming that the switch always turned the fans on when it turned on the compressor. If thats not right, then like you say, I would presumably be able to not hookup that wire and continue to use my current relay that turns the fans on now when the A/C is on.

Also, in looking at the diagram again, I realized that the trinary switch will be installed into the drier, which will be put at the front of the car. I assumed that the wire which I was going to run to the compressor would have to run to the trinary switch first, then on to the compressor. The wiring diagram provided by VA is wrong I think on how the A/C thermostat is wired in with two blue wires.

Funny thing is, I just finished wiring my entire car with an American Autowire setup and a lot of customizations, and this A/C wiring is just plain confusing. I think the problem is the vague documentation provided by VA and/or the 'one size fits all' diagrams that don't sync with the actual hardware they provide.

Thanks for your help.

-Kevin
 
#6 ·
Yes, the 3rd function is there to override the engine fans when the pressure in the ac system reaches a preset pressure(probably around 250) and it is not necessary to use that function if you already have your fans wired to come on when your ac comes on. The 3rd function is a completely seperate circuit so you can ignore it.
Remember that it actually only takes 1 wire to run your air conditioner. That wire is the one to the clutch. Everything else simply breaks that circuit.
Gary
 
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