2 stage wiring

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GCC

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Hello,

To make a long story short, I am wondering what would happen if the Y1 and Y2 wires were crossed going into the condenser unit outside on a 2 stage compressor. I wasn't seeing the compressor kick on when the stat said "stage 1". The inside blower motor was just blowing air around inside and it would stay on for a while without the outside unit kicking on. It only kicked on when it went to stage 2. When I looked at the schematic it looked as if the wires were crossed in there. So I swapped them just to see. Now it kicks on when it says stage 1, but I don't notice it necessarily changing speeds when it goes to stage 2. It now at least runs in both stages.

Like I said, long story as to how I got here, but...shouldn't the compressor outside kick on in stage one? Now that I switched the wires, it kicks on at stage one and stays on when it kicks into stage 2, although I don't see a difference in speed. Is that hat normal if it is now working correctly? Or should I switch them back and leave it alone?

Thanks,
 

Fitter30

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Normally yellow is y1 and blue is y2
But turn power off to furnace swap wires power furnace back on with a electronic thermostat theres a 5 minute time delay after power comes back on.
 

GCC

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Normally yellow is y1 and blue is y2
But turn power off to furnace swap wires power furnace back on with a electronic thermostat theres a 5 minute time delay after power comes back on.
Well originally y1 was going to blue and y2 was going to yellow. That was when stage 1 had no compressor action. I swapped them and now y1 goes to yellow and y2 goes to blue. Now the compressor kicks on for stage one. It just made me nervous that there is no difference in the behavior of the outside compressor fan from stage 1 to stage 2. I’m not sure how they are supposed to behave - never have it much thought until now. Like I said, long story but wanted to check.
 

Fitter30

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Well originally y1 was going to blue and y2 was going to yellow. That was when stage 1 had no compressor action. I swapped them and now y1 goes to yellow and y2 goes to blue. Now the compressor kicks on for stage one. It just made me nervous that there is no difference in the behavior of the outside compressor fan from stage 1 to stage 2. I’m not sure how they are supposed to behave - never have it much thought until now. Like I said, long story but wanted to check.
without knowing brand and model can only guess. Fan speed either pressure or coil temp.
 

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without knowing brand and model can only guess. Fan speed either pressure or coil temp.
Bryant 127ana060-a

Had issues a few years back with it. A switch of some kind broke in there so they bypassed it. I don’t think they would have hooked it up wrong, but…I wasn’t sure why the stage 1 wasn’t running the compressor at all. I wasn’t sure what the behavior should be. And can having them switched hurt anything if it is wrong?

Here are pics of the wiring at the stat, the furnace, in the condenser, and a schematic.

If I am right, Y1 is black, y2 is yellow. According to the schematic, y2 should go to blue and y1 should go to yellow/pink. But in mine you can see y1 (black wire) goes to blue and y2 (yellow wire) goes to a yellow wire.

The blue wire goes down to the compressor and comes back a red wire. The yellow wire connected right to the contact switch.

It’s not pictured here but today I switched them. So yellow from the inside now goes to blue and the black from inside now goes to yellow. Wondering if that was ok to do.
 

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Fitter30

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Looks right. Having y1 & y2 swapped compressor would only run when 2 nd stage called would run at 100% capacity and if stat was set at 75° it would cycle 76° to 76.5. Would depend on the offset for 2 nd stage. This problem shouldn't shorten the life of the compressor.
 

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Looks right. Having y1 & y2 swapped compressor would only run when 2 nd stage called would run at 100% capacity and if stat was set at 75° it would cycle 76° to 76.5. Would depend on the offset for 2 nd stage. This problem shouldn't shorten the life of the compressor.
Thanks for looking. Ok so if that pic looks right then I need to switch it back to look like the pic? I guess I’m reading the schematic wrong.
 

WorthFlorida

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Your model is a two stage cooling (two stage compressor). Is your issue about stage 1 not running in Cooling mode not Heat mode? If you're in cooling mode and stage 1 the compressor is not running but only when you get to stage 2, switching the Y1 and Y2, stage 2 may not kick in if it is a bad compressor or something on the controller board is bad. The schematic does not seem to indicate a two stage compressor so I'm assuming it's for a single stage using mistakenly placed at the factory, but I can be wrong.

When the thermostat calls for stage 1 and things are wired for stage 2 (reversed) the compressor may not kick in until stage 1 of the compressor is running first. So when stage 2 is called for stage 1 of the compressor kicks on with y1 & y2 reversed. I'm not 100% on this but I had a two stage Carrier commercial unit at my church and there were two sets of start and run capacitors, one for each stage. The schematic doesn't show this. The Bryant brochure reads a two speed motor where "low-stage" will operate perhaps 80% of the time.

To check out if you have it wire correctly. in Cool mode, set the thermostat so it is in stage 1 and the compressor is running, after a few minutes lower the thermostat 5 degree cooler, (at least three degrees lower) for stage 2 operation. Do check that the compressor is running but see if you can tell it is running at a higher speed. Two stage cooling and heating are controlled by the thermostat. Usually if the set temperature and room temperature is more than 2 degrees, stage 2 is called for.

Though HVAC industry use a fairly standard color code scheme, there is no written standard. Some installed wire available at the time and may not have been thermostat wire, so colors can be different. As long as the same colors match from one end to the other is all that is needed. My next door neighbor's home, the outside compressor wiring is telephone wire, 24 gauge and telephone color code. That is undersized for the compressor contactor.
 

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Your model is a two stage cooling (two stage compressor). Is your issue about stage 1 not running in Cooling mode not Heat mode? If you're in cooling mode and stage 1 the compressor is not running but only when you get to stage 2, switching the Y1 and Y2, stage 2 may not kick in if it is a bad compressor or something on the controller board is bad. The schematic does not seem to indicate a two stage compressor so I'm assuming it's for a single stage using mistakenly placed at the factory, but I can be wrong.

When the thermostat calls for stage 1 and things are wired for stage 2 (reversed) the compressor may not kick in until stage 1 of the compressor is running first. So when stage 2 is called for stage 1 of the compressor kicks on with y1 & y2 reversed. I'm not 100% on this but I had a two stage Carrier commercial unit at my church and there were two sets of start and run capacitors, one for each stage. The schematic doesn't show this. The Bryant brochure reads a two speed motor where "low-stage" will operate perhaps 80% of the time.

To check out if you have it wire correctly. in Cool mode, set the thermostat so it is in stage 1 and the compressor is running, after a few minutes lower the thermostat 5 degree cooler, (at least three degrees lower) for stage 2 operation. Do check that the compressor is running but see if you can tell it is running at a higher speed. Two stage cooling and heating are controlled by the thermostat. Usually if the set temperature and room temperature is more than 2 degrees, stage 2 is called for.

Though HVAC industry use a fairly standard color code scheme, there is no written standard. Some installed wire available at the time and may not have been thermostat wire, so colors can be different. As long as the same colors match from one end to the other is all that is needed. My next door neighbor's home, the outside compressor wiring is telephone wire, 24 gauge and telephone color code. That is undersized for the compressor contactor.
I noticed that in stage 1 the fan outside was not running. The blower inside was but the outside unit was not. It made me check out the schematic and it looked to me like the wires should be switched so I switched them. Now the outside unit does kick on in stage one but it doesn’t go “faster” when it kicks into stage 2. It’s just puzzling but there Is very little info I can find on it. Thanks!
 

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According to the wiring diagram compressor is single speed with a loader solenoid y2 energizes a coil cs. Need a amp meter or gauges to see the difference unless you can turn cs on and of and hear the little difference in the sound. Condenser fan runs anytime compressor runs.
 

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According to the wiring diagram compressor is single speed with a loader solenoid y2 energizes a coil cs. Need a amp meter or gauges to see the difference unless you can turn cs on and of and hear the little difference in the sound. Condenser fan runs anytime compressor
I just checked. Doesn’t seem to draw any more amps when stage 2 kicks in. So it seems like my choices are:

1. Put wiring back to originally how I found it. This means nothing running outside in stage 1 but blower motor running inside.

2. Leave it as is with it switched so the outside unit kicks in for stage one and doesn’t change for stage two.

?

Weird. I know there was an issue a few years ago and they disconnected the pressure sensors. Did they maybe disconnect something else along that circuit that would prevent stage 1 from running?
 

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There is a high and low pressure switches. Low is for low charge or out of refrigerant, high is for dirty condenser or fan motor not running. Have a volt meter?
Y1 to C 24v calling
Y2 to C 24v calling
If 0 v not calling
 
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WorthFlorida

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For now leave it at number 2.
Just to verify, this is for cooling only. Since it is not a heat pump, your only source of heat via electric heating elements in the air handler. For heat, stage 1 will have no compressor, only the blower will run and the electric elements will be on, if you have electric heat.

Does your thermostat display if you’re in Stage 1 or 2? What is the thermostat model please.
 

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For now leave it at number 2.
Just to verify, this is for cooling only. Since it is not a heat pump, your only source of heat via electric heating elements in the air handler. For heat, stage 1 will have no compressor, only the blower will run and the electric elements will be on, if you have electric heat.

Does your thermostat display if you’re in Stage 1 or 2? What is the thermostat model please.
Yes, cooling only. It’s a gas furnace for heat and a 2 stage compressor for cooling. Yes, it will display stage 1 or stage 2. Honeywell:

Model# RTH9585WF
 

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Ok...did some voltage testing...not sure what to make of this...

When stage 1 is on and Y1 goes to the contactor and Y2 goes to the compressor solenoid, the compressor comes on BUT both Y1 and Y2 are showing 24V.

When Stage 2 is on in the same setup up it is the same reading.

When Stage 1 is on an Y1 goes to compressor Solenoid and Y2 goes to the contactor, Y1 shows 24v and y2 shows 8v. Nothing comes on. Probably because Y1 is carrying the 24v and not turning on the contactor. So it makes sense to wire Y1 to the contactor the way the schematic shows instead of the way it has been, right?

When stage 2 is on in the same setup they both show 24v.

It seems like when Y1 goes to the contactor and y2 to the compressor, the way it is supposed to, something is energizing the Y2 wire that shouldn't be, but I don't know what.

Is there a problem with the way the contactor is wired?
 

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WorthFlorida

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it looks like the contactor is wired correctly.

I was just ready to ask for voltage readings and thank you to have done it. The schematic does show both Y1&Y2 connected at the solenoid but Y2 is via the CS. The schematic only shows the CS coil, not it's contacts(?). Can you get a picture of the CS. I never worked on this type of two stage so I'm suspecting the is another set of high voltage wires going to the compressor from the CS relay. Y1&Y2 are both connected to the contactor should a thermostat only apply 24v to Y2 only for stage two. I believe this eliminates a second start capacitor for the compressor and fan motors.

I have the same thermostat. Just to be sure do the same checks with y1 and y2 disconnected at the thermostat And I'm sure the thermostat is good.

As of now, stage one does run the compressor, it's stage two that is questionable?

Caution on this contactor, one side (hot) is shunted and the other has the contacts. When off or open, there is still 120v past the contactor on the shunted side. Usually replacements are double sided single throw to open both sides.
 

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Y2 is the only thing powering that solenoid. Have you disconnected y2 at condenser ? What is the brand and model of thermostat.
 

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it looks like the contactor is wired correctly.

I was just ready to ask for voltage readings and thank you to have done it. The schematic does show both Y1&Y2 connected at the solenoid but Y2 is via the CS. The schematic only shows the CS coil, not it's contacts(?). Can you get a picture of the CS. I never worked on this type of two stage so I'm suspecting the is another set of high voltage wires going to the compressor from the CS relay. Y1&Y2 are both connected to the contactor should a thermostat only apply 24v to Y2 only for stage two. I believe this eliminates a second start capacitor for the compressor and fan motors.

I have the same thermostat. Just to be sure do the same checks with y1 and y2 disconnected at the thermostat And I'm sure the thermostat is good.

As of now, stage one does run the compressor, it's stage two that is questionable?

Caution on this contactor, one side (hot) is shunted and the other has the contacts. When off or open, there is still 120v past the contactor on the shunted side. Usually replacements are double sided single throw to open both sides.
Doesn’t the schematic show y2 connected to the common side (after it it goes through the cs) and y1 connected to the opposite side of the contactor? I feel like I should switch the y2 to the same side as the common side of the contactor. (On the 24v) this way when y1 kicks on it isn’t energizing y2 being connected at the same spot??

As of now, stage 1 does not run the compressor - it doesn’t kick on until stage 2 gets energized. But if I switch them it starts right away, but in stage 1 it energizes both y1 and Y2.

I feel like I should wire it so y2 goes to blue (cs), y1 goes to contactor, and then move the cs return to contactor to where the common side wire connects to the contactor,
away from the same side that y1 comes in. Would that be ok?
 
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WorthFlorida

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I found the schematic on line so we have a nice and clear picture. You want to leave the system where stage 1 is turning on the compressor for cooling.

Looking at the schematic, Y1 goes through the LPS and HPS switches and then to T1 of the CTD (compressor time delay). When the CTS relay contact closes, it brings the Y1 24v ac to the coil via the T2 terminal of the CTD, then to the contactor on the VIO wire. Do note that your thermostat also has a time delay, therefore, Y1 power at the contactor may not be immediate as the thermostat will read "waiting for equipment". I'm not sure about stage 2 cooling.

Y2 goes through the CS coil and the other side of the coil via the RED wire to the common side of the contractor. . (I was wrong on my assumption in my previous post)

The million dollar question is how does the compressor change to high speed with Y2? It's why I asked for picture of the CS.


Screen Shot 2022-02-19 at 1.16.38 PM.jpg
 

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Doesn’t the schematic show y2 connected to the common side (after it it goes through the cs) and y1 connected to the opposite side of the contactor? I feel like I should switch the y2 to the same side as the common side of the contactor. (On the 24v) this way when y1 kicks on it isn’t energizing y2 being
I found the schematic on line so we have a nice and clear picture. You want to leave the system where stage 1 is turning on the compressor for cooling.

Looking at the schematic, Y1 goes through the LPS and HPS switches and then to T1 of the CTD (compressor time delay). When the CTS relay contact closes, it brings the Y1 24v ac to the coil via the T2 terminal of the CTD, then to the contactor on the VIO wire. Do note that your thermostat also has a time delay, therefore, Y1 power at the contactor may not be immediate as the thermostat will read "waiting for equipment". I'm not sure about stage 2 cooling.

Y2 goes through the CS coil and the other side of the coil via the RED wire to the common side of the contractor. . (I was wrong on my assumption in my previous post)

The million dollar question is how does the compressor change to high speed with Y2? It's why I asked for picture of the CS.


View attachment 81223
One of the pressure switches went bad a few years back so they cut them out of the circuit. I don’t see a time delay - the y1 (former y2 when wired wrong) goes straight to the contactor. But it’s been wired so y2 was that wire that connected to the contactor and y1 was going to the cs. I changed it so y1 is now correct. I think it’s always been wired wrong. But even with y1 correct, when it kicks on it energizes both y1 and Y2. I really think that that y1 should be alone on one side of the contactor and y2 and the common on the other. I think when y1 is getting 24v it is always energizing y2 through as they are both connected to the same side of the contactor.

I moved it so it matches the following:

Y1 goes straight to the right side of the contactor. Y2 goes to cs and comes back to the left side of the contactor. Common goes to the left side.

I can’t get a pick of the cs - it’s at the very bottom of the compressor.

I’ve nervous to turn it on though! Lol! I think it should work this way…can I try it or do you see an issue with it?
 
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