Technical Wiring and Trinary Switch (basics)

Ok.
Planning on having my main fan come on and off with temp sensor.

But AC condensor fan ...... whats wrong with running a binary switch like this ...



Only downside I can see is that the condenser fan will always be running whilst AC is on via switch in cab. But then ..... how does a trinary switch fix that.

Keep it simple though

 

You need your fan running constant with ac on anyways.
Don’t see an issue with this set up.

 

My thought is with the trianary switch the fan cycles with the high low changes in the ac head pressure.

 

Thats what I was lead to believe as to why to use a trinary switch ...... engages and disengages at certain pressures ....
but then

why do we have binary switches at all ?

 

Binary will shut off the compressor if the head pressure goes stupid. Running a mechanical fan makes this more simple. Just use the binary. But we can't do the mechanical fan in every build. Had an electric fan on my old coupe with the tri mary switch. Saw the fan slow on the highway with the air on.Then it would cycle back on as the head pressure rose.

 

Dont know if it makes a difference but running two electrical fans (seperate circuits) due to space.

Main Engine Fan via a temperature sensor signal (on at ~180* degrees) - seperate circuit.

Then this AC/condenser one.

 

Each of your fans should have its own relay (failsafe). Just jumper the wire shown to trigger the single relay to the second relay, so it triggers both (so long as you have a mechanical fan). If you only have electrical fans, your wiring should include a third relay, for at least one of the fans, that goes to a coolant temperature sensor.

 

Trinary does both, protect the compressor and run the fan, binary only protects the comptrssor

You can use a trinary in place of a binary but it costs more and you are only using the one part of the switch.

 

I have 2 electrical fans ... no mechanical.

Currently .....

Main engine fan is on a relay to go with temp sensor in block.

AC/Condensor fan is on a seperate realy as per wiring diagram using a binary switch. Just deciding if worth going to to a trinary switch.

 

But if the trinary cuts off the compressor ...... how does it still run the fan.
Meaning what does the wiring for that look like.

 

In this drawing, the condenser fan will only come on when the head pressure hits a certain point. So it should cycle off going down the road if the heat load is low. That's the basic setup Freightliner has used for years on trucks with AC. The only difference is that the binary switch is an input to the engine ECM and it turns the fan on and off. A trinary switch would control the engine fan and also protect the compressor from an extreme pressure condition by shutting it off.

 

It is multiple switches in one body.

 

Gotchya.
Someomne got a wiring diagram of what that looks like and how it operates.
Meaning....

a) wiring
b) This is how it works with LCOP and HCOP and fan signal etc.

 

There are a lot of designs for the wiring, for example terminal 4 could be wired to a ground to have terminal 3 provide ground side relay at a 5 prong fan relay or to a ign current side.
Basically terminal 2 is the wire coming from the A/C control in the car(usually a thermostatic switch) to provide current to the compressor, terminal 1 is going to continue the circuit to the compressor once the trinary is installed.

 

Not the best photo, but you can get the real deal from the online Vintage Air catalog.

 

Thanks. Yes have seen that VA trinary link. Part is I can follow the wiring ...... but dont quite get how it actually works if that makes sense.
I wont have it linked to a temp sensor or thermostat in radiator (pin 86).

So that makes me thing that the AC switch in dash turns the signal on to activate both the AC compressor and FAN both via signal to pin 86.
BUt what happens when pressure gets to high - isn't the circuit just going to be cut .... and both fan and compresser both stopped.
Or is the trinary switch internally handling that and will close down the compressor circuit (wire to the compressor) but keep open/active the wire to the fan.

 

The trinary switch is designed to close circuit to fan, when pressure gets to a certain level. That way fan comes on, and cools the condenser, bringing the operating pressure down. If the pressure in system gets too high, or too low, then the binary part of that trinary switch, will cut out the compressor, for safety reasons.
I didn't look it up yet, but I think Vintage Air had the pressure set points listed in their description, or refrigeration basics article.

 

^^^^This

 

Do you need to add a temp switch in the circuit for engine cooling?

 

The binary switch controls the compressor based on low (=on) and high (=off) pressure in the refrigerant system.

The trinary switch does that too, but in addition (the ‘third’ part) can activate an electric fan to increase the efficiency of the condenser in cooling the refrigerant and reducing refrigerant pressure.

(As I understand it)... there is no temperature input to the trinary switch - it only knows about the pressure in the refrigerant system. The trinary switch is connected to the fan relay, which is how it can control the cooling fan.

The cooling fan in my car is controlled by a) engine coolant temperature, b) a rheostat I can control, and c) the trinary switch.

Does that make sense?

My knowledge comes from recently wiring my system.

 

Almostdone is right on the tri-switch is like having three separate pressure switches one to protect the system in case it goes low on Freon kepting the compressor off until the system has around 14 psi . The second cycles the engine cooling fan to maintain around 130 psi .
The third turning the compressor off when the pressure exceeds 190 psi . The Binary switch just gives you the hi/ low safety switches . These pressures are approximate they’re not adjustable they’re fixed within the switch . The engine cooling system is operated by its own controls and is paralleled into the same fans .

 

Where is Moriarity when you need him,,,,,,,sounds much more street rod than traditional.
Actually,,,,it reminded me of my OT Honda Accord .

Lol,,,,,carry on .

Tommy