How To Wire An Advent Air AC System To A Two-Wire Furnace

Updated 06/10/2024 | Published 07/18/2023

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Digital Multimeter with 42" Long Test Leads - LED Display

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Question:

I recently bought the Advent Air RV Air Conditioner System - Single Zone - 13,500 Btu - White to replace my 10 year old Dometic penguin AC. The Dometic had 3 wires going to the thermostat and 2 wires going to the furnace. The Advent needs 4 wires going to the thermostat and one wire going to the furnace. My Suburban furnace has two blue low voltage wires that connected to the two wires from the Dometic AC. I am not sure how to wire these low voltage wires. I thought it would be compatible. I should be able to run an additional wire between the furnace and the thermostat to make it 4 wires to the thermostat, but then I am not sure how to hook up the AC to the thermostat using 1 wire. Any help would be appreciated.

asked by: Michael S

Expert Reply:

Typically if there are two wires running from the furnace to the AC system then it means that the furnace has power already connected to it and it sends that through one of the wires up to the AC until the system calls for heat, at which point the relay will close and send power back to the furnace through the other wire. You'll want to connect the brown and white furnace wire from the controller # ACRG15 to the other wire send power back to the furnace.

To determine which wire is which you can use a multimeter # PT89ZR and place one lead to a good ground and the positive lead to either wire. One wire should read 12v DC and would be the power running from the furnace to the AC. You'll connect the AC wire to the other furnace wire so it can send power to furnace to activate it as needed. The power wire can just be capped off with some electrical tape.

expert reply by: Kevin C

John L.

6/4/2024

I bought the acm150lp unit it said it was compatible with any old unit my old unit don’t have a plug on it so I’m unsure of the wiring on the new unit

Kevin C.

6/4/2024

@JohnL If your old system was hardwired and doesn't have a 6 or 9-pin connector then you would need to replace the air distribution box as well in order to plug in the # ASA86YR (ACM150LP). For this unit there's a manual option # ACDB with the controls on the air distribution box or an option with a wall-mounted thermostat # ACRG15.

Helpful Links

tv-review-advent-air-ceiling-vent-assembly-acdb.aspx

tv-review-advent-air-low-profile-rv-air-conditioner-with-start-capacitor-asa99yr.aspx

tv-review-advent-air-rv-air-conditioner-vent-thermostat-assembly-acrg15_1.aspx

Frank R.

6/8/2024

I bought an advent 13500btu to replace my dometic ac with the advent control box and thermostat getting e5 on thermostat any help would be appreciated 3

Kevin C.

6/8/2024

@FrankR An E5 error code simply means there's a communication error between the relay box # PXXACRG12RB and the thermostat. If you're hooking it directly to the relay box without any extra wire and it's wired correctly and you're still getting the E5 error then either the relay box or thermostat is defective and needs to be replaced. Just to make sure you have it wired correctly I've listed the wire colors from the relay box and their connections on the thermostat below: Blue: A Purple: B Green: COM Red/White: 12v

Frank

6/8/2024

@KevinC where do I hook The heater wire too I have a thin white and thin red that was in old box which one goes to the heater wire thanks

Kevin C.

6/10/2024

@Frank The # PXXACRG12RB has a brown/white wire that will need to run to the furnace. For the trailer wiring you would need to put 12v power to either line and see which one sends power to furnace to turn on or if you still have remember which wire from the old unit went to whichever wire and can look up the old system's wiring diagram to see which wire is for power.