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Kcrand36, HVAC Mechanic
Category: HVAC
Satisfied Customers: 77
Experience:  Owner at Advantage Repair
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I have a RUUD Achiever 90 Plus (UGRA-07EMAES). I need to

Customer Question

I have a RUUD Achiever 90 Plus (UGRA-07EMAES). I need to wire a relay that will energize anytime the blower runs (heat, cool or fan only). I understand that the HUM (humidifier) terminal is a line level connection that only energizes when the blower turns on while the burner is lit and not when the blower is on while cooling or when the fan only is running. If my understanding is correct, then using the HUM terminal won't work for my needs. I have not purchased the relay yet, so any suggestion for a hookup that uses line level power or 24v power will work.
Submitted: 1 year ago.
Category: HVAC
Expert:  Kcrand36 replied 1 year ago.

Hi Dave, I am Kevin from JA, let's see if we can solve this together.

What exactly do you want to do?

Customer: replied 1 year ago.
I have a whole house air scent system that dispenses in the air stream of the HVAC duct. The scent unit powered separately and independently from the furnace, but the scent unit only turns on when an air flow switch senses air flowing and activates the air flow switch (which completes the remote senor circuit of the scent unit) . The air flow sensor is too finicky and unreliable, so instead of using the mechanical switch of the air flow sensor to turn the unit on, I want the relay to complete the remote sensor circuit.
Customer: replied 1 year ago.
Basically, the air scent unit can be programmed to specific times. If it is on a "run" time, then the scent unit will only actually activate if the air flow switch detects that the ran is running. The scent system has a pair of wires that plug into the scent unit and the other end of the lines plug into the air flow switch terminals. When the air flow switch detects air running, the pressure causes the circuit from the low voltage lines to connect. I want to run the wires from the scent unit to the relay so that when the relay is energized by the blowing turning on, it will complete the circuit for the scent unit so it can turn on.
Expert:  Kcrand36 replied 1 year ago.

ok, I understand. I would probably break the blower motor (power) circuit then. Depending on the voltage of your furnace, air handler, will depend on the voltage of the relay.

Customer: replied 1 year ago.
If there is no 24 volt option, which is fine, then my line level is 120v. I'm hoping there are terminals to connect to, otherwise, do I just need to wire the relay into the blower lines?
Expert:  Kcrand36 replied 1 year ago.

I would not think there would be a 24 volt option. You want the "scent" to be dispensed either heat or cool, (every time the fan runs). The best for this would be to take the lead off the circuit board feeding the blower motor (120 or 240) getting the proper relay 120 or 240, energizing the relay with the blower motor circuit coil and also energizing the blower through the relay. Therefore every time the blower originally had power, it would power the relay, energize the blower and also energize the scent. That would be a mars 92341 if 120V coil relay .... let me know if different.

Customer: replied 1 year ago.
Sounds like a plan. Thanks for the assistance.
Expert:  Kcrand36 replied 1 year ago.

I'm sorry for the delay, either I'm computer illiterate or we are having a problem with the website.. But if you need help to hook up or more, let me know, I can be here.

Thanks for using JA......


Expert:  Kcrand36 replied 1 year ago.

Hi Dave,

Just checking in to see if you were happy with the service you received from Ja.

If you have any questions or reservations, please let me help you make them right.

If you could take a minute or two to rate the service you have received, it would be very helpful to me to help others. I would like to close this call if your happy and help others who need help.

Thank you very much


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