Low pressure sensor/contactor

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  #1  
Old 05-22-19, 10:33 AM
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Low pressure sensor/contactor

Im not getting the 24vlt at the contactor on my older ge weathertron.
Can this low pressure sensor interupt the signal to the contactor to prevent it from engaging it .an no voltage ?
Theres no 24 volts to it ..Manually pushed its fine..
Diagram shows the low pressor sensor is on the same connection as the blue wire to contactor off stat wiring..

Thanks
Pics in a bit
 
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  #2  
Old 05-22-19, 10:59 AM
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Theres the " newer" sensor..gotta find my old one..
Along with diagram .Blue wires show it goes to it off contactor but theres a few other wires on diagram...nothing showing on yellow wire either.[no 24volts]
Any info is appreciated

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Last edited by PJmax; 05-24-19 at 08:27 PM.
  #3  
Old 05-22-19, 03:05 PM
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Your photo doesn’t show a sensor of any kind.
That’s a solenoid coil.
 
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Old 05-22-19, 04:28 PM
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As mentioned.... that's the solenoid coil off the heating/cooling reversing valve. That solenoid will share the blue/C side of the contactor as it needs common to operate.

A pressure switch will be directly screwed or soldered into one of the refrigerant lines.

Example...................
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  #5  
Old 05-23-19, 11:59 AM
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Thanks .Yea switchover valve solenoid i mean.-diagram calls it.

Im replacing my 2 wire tranformer with the same ...-new one is 5 wire ..do i need to cap off the red ,orange ,an black/red wires on transformer ,an stay with the 1st 2 - white an black ? hooking the 240 in .
An is this built in 3.7 amp breaker built in on the side trippable on just the 2 wires ill be using off it ?
..getting pic

 
  #6  
Old 05-23-19, 12:02 PM
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Here is a pic .. new an old

old wiring has 2 blue on same lead on one ,an fused black wire going directly into transformer
Should i wire it white common to black fused line coming in an the orange 240 to the 2 blue coming in ..?

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Last edited by PJmax; 05-24-19 at 08:31 PM. Reason: resized pictures
  #7  
Old 05-23-19, 12:53 PM
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Looks like you'll be using the white and orange wires. The others must be capped off.
 
  #8  
Old 05-23-19, 12:59 PM
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Ok ill hook up 240 orange .
.Does common [white]on new part go to the old fused black wire ?
only other choice is the 2 blue that are together ..
 
  #9  
Old 05-23-19, 06:20 PM
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Here is a diagram
Is the fused line -glass fuse on. Old black wire the 24.Or the 240 ..best i recall on testing it was incoming..
ill reest it with new part disconnected. ---
but i must note the wire size on the 2 lines w 2 wires striped wire is thicker ..

The black fused an 2 blue on 1 side are same smaller size

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Last edited by PJmax; 05-23-19 at 07:16 PM. Reason: resized/labeled picture
  #10  
Old 05-23-19, 07:06 PM
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That fuse is on the 24v side of the transformer.
 
  #11  
Old 05-24-19, 12:39 PM
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This is odd .
i wired it just as old one ..
like you just showed .

The 2 blue /black ..to New white an other 2 brown/ red to New orange ...which (read 240) on both

An the smaller yellow 24v off transformer to black [glass fused)
an blue 24 to 2 blue .

Nothing reading off 24v side of transformer! Again..011 i get
I manually can press contactor an cold air kicks in..

Any ideas?




Is that built in 3amp fuse on transformer trippable? With only wiring 2 in an capping other 3 ?


Ill check glass fuse too but that is after transformer

Note fan control on inside stat didnt kick in with it newly wired .but works when contactor is pushed in, manually with plastic ,to test ..
 
  #12  
Old 05-24-19, 08:26 PM
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Your new transformer has a circuit breaker on it ?
If you have 240v to it but nothing coming out..... that circuit breaker is probably tripped.
 
  #13  
Old 05-26-19, 04:16 PM
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Got it back together ..Transformer working!
Its doing same thing still.
I tested transformer an secured wiring an tighter bolt to secure it ..
Im getting the 240 an the 24 too ..
I did all the ohms tests on the 2 wire 24 volt off the transformer..an all the way to contactor an even to stat board in unit...
All cleared but at the relay ,jumper,with it off it might not read..(I need to test it with it on next)
No shorts so far--
I still need to find the 2 wires to the low pressure solonoid[diagram calls it switchover valve solenoid]
an see if thats where the 12v ends .
The air temp stays good an cold a long time though when contactor is engaged a while.

What all should i test/ look at from here. ,along with "switchover valve solenoid" ?
maybe that relay that the 24v goes to with blue jumper wire?
An is it ok to keep the 2 breakers in on at..1 240v in transformer an other at 24 v?
Thanks!!
 

Last edited by trotter321; 05-26-19 at 05:04 PM.
  #14  
Old 05-26-19, 11:46 PM
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We already discussed this..... the switchover valve is not the pressure switch. That valve changes the refrigeration flow for heating and cooling.

You lost me with two breakers. I thought you said a circuit breaker built into the transformer and a fuse on the 24v side.

Be very careful manually holding in the contactor.

The 24v from that transformer isn't going to the contactor. The 24v from your thermostat via the Y connection is what activates the contactor.

Is this a packaged unit....... everything outside.... air handler and condenser ?
Then the 24v from that transformer goes to the thermostat via R and then gets sent to the contactor on Y.
 
  #15  
Old 05-27-19, 07:56 AM
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I always use plastic to wedge contactor.,an with it off..!
Rarely do i touch wire..i hook em up ,power off,( if needed run caps grounded out )an turn on with no hands touching !
There is 24 v before an 24 after the switchover valve solenoid.-..YELLOW from stat an BLUE wire. ..

Maybe the 2nd one off transformer fused line -is the issue ?


That red wire 24v afterthe glass fuse goung into what looks like the fan relay ends the 24v there ..it has a jumper wire an looks like other wire goes to defrost box..
Is that maybe why its not getting to contactor ? How do i test it..

I think pic is in other thread ..cant load anymore
.
Thanks
 
  #16  
Old 05-27-19, 08:56 AM
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Yes old package unit .Ge weathertron .

Later im gonna replace it though ..
The glass fuse an a fuse on NEW transformer- i mean 2 "fuses " sorry
 
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