Compressor Wiring-56K Be aware Large Pics

[redstang308]

ok here we go,
I am trying to wire the compressor to start up with a relay from a 12V line. In other words I am making a system for the computer to turn on the compressor amd fan. The input line from the computer is a 12V, so I need to find a relay that would handle this. Anyone know where to point me? I have looked around everywhere.

Also I have a AC unit that I need a little help with the wiring of it. I want to fan to be always on low and the compressor to be started.

I am not too good on putting my thoughts into words so please bear with me here.
<IMG SRC="http://home.comcast.net/~redstang308/comp1.jpg"
<IMG SRC="http://home.comcast.net/~redstang308/comp2.jpg"
<IMG SRC="http://home.comcast.net/~redstang308/comp3.jpg"
<IMG SRC="http://home.comcast.net/~redstang308/comp.jpg"

[redstang308]

also does anyone know what the operating range for the built in thermo? As far as the one that tells room temp?
Thanks

[wdrzal]

you just need a magnetic contactor with a 12 volt coil. the contactor needs to be the correct size for your compressor. walt

any electrical supply or hvac/r supply will have them.

you need a dpst (double pole single throw)with 12v coil, must be rated for compressor electrical load. there are open and enlosed type. the double pole will allow you to break L1 & L2 walt

[Stewie007]

And make sure you do your research before you go and know exactly what you want to buy, name and all. Last time I went into an HVAC shop, I couldn't get them to understand what I meant by a solderable union.. A Half Union with ends that I can braze... yeesh.

[wdrzal]

And make sure you do your research before you go and know exactly what you want to buy, name and all. Last time I went into an HVAC shop, I couldn't get them to understand what I meant by a solderable union.. A Half Union with ends that I can braze... yeesh.


yea,LOL what we call stuff in the feild dosn't jive with their real name. ;) walt

i'll say 1/2 inch copper to copper union,I don't know if thats the right name or not.

[Stewie007]

Well, what I wanted was a half union for a flare, with the other side being brazable, like the ones you typically find in a TXV.

[wdrzal]

Well, what I wanted was a half union for a flare, with the other side being brazable, like the ones you typically find in a TXV.

Hmmmm, I know what you mean,but they come with the control,I never bought or ever think I seen one seperate. were you able to buy one? walt.

[Stewie007]

Well, I have a feeling they're wholesale only for manufacturers. Getting my hands on one would probably require a special order. I was not able to acquire one. Instead, I simply bought some unions from lowes, double sided for two flares. Wont hurt anything.

[redstang308]

what about wiring? anyone got a diagram?

[wdrzal]

It would be hard to draw you a diagram not knowing excatly what you have and what you want to do.

I would recommend if you are not familiar enough with control wiring to draw your own diagram that you do not initially contol the on/off function of your compressor by your pc.Their are a lot of things you could do wrong to fry your pc.Keep them seperate at first.get everything working then you can intergrate the two later.Keep in mind that cooling systems do not provide instant cooling,they need a small amount of lead time.I think if I had both start off one button I would use a time delay relay on the pc so the cooling unit starts first by at least 30 to 60 seconds or more,that would insures the processor would not overheat before the system started to cool. I do not know if this is necasary or not but thats what I would do. I will try to answer your wiring questions as best I can.

Walt

[redstang308]

how bout a diagram of a standard AC system to a on/ off switch

[gkiing]

Hmmmm, I know what you mean,but they come with the control,I never bought or ever think I seen one seperate. were you able to buy one? walt.

yes you can get these, their usually sae flare on one end and the other end has an inside diameter made to match the o.d. of a copper tube and can be soldered.

by the way that tar tape on the suciton line on that a/c is awful, that stuff gives me a migrane for hours whenever I use it.

[wdrzal]

are you leaving everything in the existing case or are you going to remount everything? If you are leaving everything as is,except for removing the evaporator of course, you can just bypass the thermostat so it runs continiously and use the existing on/off switch.Using that switch also controls fan speed. What is it a 3 speed fan. walt

[Revv23]

^i am doing something similar to that, though i would prefer something that gave me 0-100% control of fam motor, as it's high and low settings are like 100%-75% ish...

To make the compressor so it's always on, just pull the thermistor right off, the problem with this is that the LED on my AC unit reads Er instead of a temp... I really wish i had the know how to wire it up so this thermistor displayed temps on the LED... if thats even possible. any of you guys have any thoughts on that?

[wdrzal]

You can not make a 2 or 3 speed fan variable speed.
(their are ways but behond scope here,)

the display gets it input from the thermostat control,since you diconnected it,no display. You should be able to leave the thermostat control hooked up and just jumper the hot line across the 2 terminals,then your display will work and your compressor will stay running. Walt

[Revv23]

what do you mean by "hot line"? like cross the leads on the thermistor? there is two leads on it, so i think this must be what you mean.

[Marvin]

this is a nice diagram from a friend of o/c forum stockhatch :
http://www.ocforums.com/attachment.php?attachmentid=40341&stc=1

[wdrzal]

what do you mean by "hot line"? like cross the leads on the thermistor? there is two leads on it, so i think this must be what you mean.
if you are not sure,don't jump it. every control is different and since I never seen it I can not tell you fo sure.

[wdrzal]

if you use above diagram you need a spst relay w/12v coil it only breaks L1

[Revv23]

if you are not sure,don't jump it. every control is different and since I never seen it I can not tell you fo sure.


i have several pics, ill upload them tommorow.

[redstang308]

ok so do I have to keep the cap in the line with the power? Or can I remove that nad wire it exactly as shown above?

[wdrzal]

what is cap ,if you mean capacitor you absoloutly can NOT elimanate it.

oh, whats a nad? walt