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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 953
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I added a single stage air conditioner to a Bryant 350CAV080

Customer Question

I added a single stage air conditioner to a Bryant 350CAV080 gas furnace and the control board of the furnace will not energize the control wires to the outdoor unit. The furnace blower does ramp up to cooling speed but that is all.
JA: Sometimes HVAC issues that that you think will be really complicated end up being easy to fix. The HVAC Technician I'm going to connect you with knows all the tricks and shortcuts. Is there anything else important you think the HVAC Technician should know?
Customer: The thermostat is an Evolution SYSTXBBUID01-B
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the HVAC Technician about your situation and then connect you two.
Submitted: 1 year ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 1 year ago.
Hi I'm Brian and I'm here to help!I'm sure I can help with this. Can you please give me a few moments to find your manuals and I'll be right back. The only question I have is what is the brand and model of condensing unit you installed? Thanks,Brian
Customer: replied 1 year ago.
Rheem RA1360AJ
Expert:  Brian HVAC Guy replied 1 year ago.
Thank you for that. I'm looking at the furnace manual as we speak. When you hooked up the condensing unit, I'm assuming you hooked the two low voltage wires to C and Y on the furnace low voltage terminal board, correct? Also, did you go into thermostat setup and tell the thermostat you now had a one stage ac unit connected?
Customer: replied 1 year ago.
Yes I connected the 24 volt wires to the condensing unit and programmed the thermostat with the local rep's assistance.
Expert:  Brian HVAC Guy replied 1 year ago.
On the furnace control board did you connect the Y wire from the condensing unit to Y/Y2 or Y1 on the the furnace control board's low voltage terminal strip?
Customer: replied 1 year ago.
The controller is a 4 wire device connecting to the furnace controller with a molex type plug. There is a conventional low voltage terminal strip on the controller that had nothing connected to it until I attached to the Y/Y1 and the 24 volt common terminals. There is 24 volts between R and common.
Expert:  Brian HVAC Guy replied 1 year ago.
I am aware that your thermostat is a communicating thermostat to your furnace and your condensing unit is a standard straight cool non-communicating unit. It sounds like you have the stat programmed correctly since the blower ramps up when cooling is called for. What I'm asking is on the two low voltage wires that go to the outdoor unit, you connected one of them to C on the furnace control board conventional terminals and what terminal did you connect the other low voltage wire from the condensing unit to? There should be both a Y1 and a Y/Y2. Which one is the wire from the condensing unit connected to?
Customer: replied 1 year ago.
Y/Y2 is what I meant.
Expert:  Brian HVAC Guy replied 1 year ago.
Ok great! Thanks for clarifying that. That is the correct spot for it. When the system is calling for cooling there is NOT 24 volts between C and Y/Y2 on the terminal board? Also, there is a tiny computer board jumper on the furnace control board labeled ACRDJ, is the jumper shorted or open (on or off the two pins)?
Customer: replied 1 year ago.
I took it off to see if that would make a difference. It didn't.
Expert:  Brian HVAC Guy replied 1 year ago.
The ACRDJ jumper should be off for your configuration. Those are the only settings for your system. 1) the thermostat set to single stage ac (not heat pump) 2) wires connected to C and Y/Y2 and 3) ACRDJ jumper off (on one pin instead of two). There are no other settings or switches or wiring options that have any effect. You didn't say, do you have 24 volts between the C and Y/Y2 terminals when the thermostat has called for cooling? If so, then there is an issue either with the wire going outside or the condensing unit itself. If there is no voltage then I would suspect there is an issue with the furnace control board since you have met all other installation steps.
Expert:  Brian HVAC Guy replied 1 year ago.
I think I would go back through the thermostat setup and ensure those settings are correct. You have shown me that the other wiring and furnace settings are correct, perhaps the thermostat needs a 2nd go at configuration. If you'd likr to do that and want guidance, let me know and I'll be happy to help! Thanks,Brian
Customer: replied 1 year ago.
There is no power between Y/Y2. I'll check the thermostat configuration again.
Expert:  Brian HVAC Guy replied 1 year ago.
Just to be clear, you mean no 24 volts between C and Y/Y2 when stat is calling for cooling and after any delays have elapsed correct? If so then yeah, I would check the stat setup. It should be as shown in THIS PICTURE -Brian
Customer: replied 1 year ago.
That's right. No 24 volt at any time over an hour of reading manuals and talking to people on the phone. Furnace blower operating continuously at high speed.
Expert:  Brian HVAC Guy replied 1 year ago.
Yeah, that tells me the thermostat is not sending a signal to the board to turn on the compressor output at Y/Y2. You may have to reboot the thermostat and get it back to out-of-the-box readiness if it doesn't seem to accept the new setup parameters and call for cooling.