Carrier furnace giving reversed polarity code
#1
11-17-18, 10:49 AM
Carrier furnace giving reversed polarity code
So for the past three day I’ve been having trouble with my flame sensor. Off and on when the thermostat would call for heat, the inducer would start, followed by the other steps. After there was a flame though, it would kick off sporadically. Sometimes after 5 secs, sometimes after 2 hours. I cleaned the sensor and for 24hrs it ran normally.
Came home from work to find furnace off with nothing running at all. Now I have a rapid flashing light which apparently means reversed polarity. Any help at all would be appreciated.
Came home from work to find furnace off with nothing running at all. Now I have a rapid flashing light which apparently means reversed polarity. Any help at all would be appreciated.
#2
11-17-18, 02:20 PM
Assume you haven't had any electrical work done lately.
Could be bad ground or bad control board. With power off use a multi-meter to measure the resistance between the white neutral from your 120v supply coming in to the furnace and the chassis. Should be close to zero.
Could be bad ground or bad control board. With power off use a multi-meter to measure the resistance between the white neutral from your 120v supply coming in to the furnace and the chassis. Should be close to zero.
#3
11-17-18, 02:49 PM
Yes it’s almost zero. Had an HVAC guy come out. Ended up agreeing that the board had shorted out. However after telling me to replace entire furnace before even getting down to the basement, he then gave me a quote for $1000 to replace the board. Is he ripping me off?
#4
11-17-18, 04:57 PM
Lots of HVAC techs are salesmen first so be aware.
Price varies based on location, time of day, day of week, and how busy. Most boards cost less than $100 from the parts counter but you pay for the installation, convenience, etc. You can order most from Amazon and have it next day to do it yourself.
If you can wait then call around for other estimates. Also good to have it PMed - cleaned and checked out.
Price varies based on location, time of day, day of week, and how busy. Most boards cost less than $100 from the parts counter but you pay for the installation, convenience, etc. You can order most from Amazon and have it next day to do it yourself.
If you can wait then call around for other estimates. Also good to have it PMed - cleaned and checked out.
#5
11-17-18, 04:59 PM
Group Moderator
I'd say $1000 is on the high side for a board replacement but cannot comment directly without knowing either the control board number or the furnace model number. Some boards are pricey.
It would be a good idea to check the flame sensor operating current in case there is a ground issue with the burners.
It would be a good idea to check the flame sensor operating current in case there is a ground issue with the burners.
#6
11-18-18, 04:12 AM
There doesn’t seem to be a ground issue with the furnace. Ordered a replacement board last night. Should be here in a day or two. It’s not below freezing here yet so we should be ok. I’m going to look at replacing it myself but if it’s to much I’ll call someone out to do it. At least I already have the part coming. Any advice on swapping boards. It seems to me like labeling cords then just unplugging and plugging in one at a time.
#7
11-18-18, 08:07 AM
Yes, label the wires first. Take a few pictures as well. Remember to cut power before you start.
When removing wires pull on the connector, not the wire. Some use needle-nose pliers for this as they can be tight. The white Molex style multi-wire connectors usually have a tab on the side you need to press in. Be gentle with any plastic board mounting tabs as they can break easily.
When removing wires pull on the connector, not the wire. Some use needle-nose pliers for this as they can be tight. The white Molex style multi-wire connectors usually have a tab on the side you need to press in. Be gentle with any plastic board mounting tabs as they can break easily.
#8
11-18-18, 09:02 AM
Group Moderator
Yes, label the wires first. Take a few pictures as well. Remember to cut power before you start.
#9
11-18-18, 09:35 AM
Thanks for the help guys. Part comes in tomorrow afternoon. Staying with family for my kids sake. It’s a bit to chilly for him. I will update with my progress.
#10
11-19-18, 02:15 PM
Well I successfully installed the new control board. Furnace fired up and cycled completely several times. Now it is giving me a code saying my pressure switch is stuck closed. Any suggestions?
#11
11-19-18, 07:50 PM
Congrats on replacing the board yourself!
You most likely pulled a rubber vacuum hose off. Double check the wiring to it as well. Pressure switches look like 2 1/2" flying saucers or hockey pucks.
You most likely pulled a rubber vacuum hose off. Double check the wiring to it as well. Pressure switches look like 2 1/2" flying saucers or hockey pucks.
#12
11-19-18, 08:14 PM
Group Moderator
Disconnect the hose from the pressure switch and see if you still get the stuck closed fault code.
A pressure switch is normally open so that if the hose is disconnected it shouldn't show closed.
If removing the hose clears that fault...... remove the hose from the draft inducer and make sure the little orifice is clean. It is a tiny hole in the bottom of the hose fitting. It will require a pin or small drill bit to clean.
A pressure switch is normally open so that if the hose is disconnected it shouldn't show closed.
If removing the hose clears that fault...... remove the hose from the draft inducer and make sure the little orifice is clean. It is a tiny hole in the bottom of the hose fitting. It will require a pin or small drill bit to clean.
#13
11-20-18, 05:29 AM
Pressure switch seems to be operating normally. Came home this morning and thermostat said 56. Set it to 70, everything fired right up. Sat in front of the furnace and it ran perfectly. I am having some whistling and other noises coming from my inducer. Anyway, reached temp upstairs and shut down. When it called for heat again though, absolutely nothing, then pressure switch error code. I have a friend of a friend who does HVAC professionally coming over (for free!!!) but figured I’d post this for any suggestions. Maybe my inducer went bad also?
#15
11-19-20, 07:01 PM
Just had some of the previously mentioned symptoms "Pressure Switch Did Not Open", and later the rapid flashing "Line Voltage Polarity Reversed" on an existing (approx. 2004 build) installed Bryant model 310AAV036070AAJA. Furnace had stopped functioning on it's own one day. After inspection of the furnace, the board and wiring, there had apparently been a short. The circuit board is an HK42FZ013. The pressure switch seemed to be functioning when tested, and the hose was in good shape with no blockages.
Purchased replacement board online, repaired one wire, labeled all wires, removed and replaced the board and wires and the furnace is now functioning properly.
Thanks for your previous posts that helped me with the troubleshooting process! It was a big help, especially the information regarding a possible "bad ground or bad board" causing the symptoms/codes.
Thanks everyone!
Tom
Purchased replacement board online, repaired one wire, labeled all wires, removed and replaced the board and wires and the furnace is now functioning properly.
Thanks for your previous posts that helped me with the troubleshooting process! It was a big help, especially the information regarding a possible "bad ground or bad board" causing the symptoms/codes.
Thanks everyone!
Tom
#16
11-19-20, 07:27 PM
Group Moderator
Welcome to the forums.
Thanks for letting us know you were helped.
One other thing to keep in mind on older furnaces is the screws that hold the burner in as well as the screws on the control board. Those screws get rusted and loose. Any loss of ground can cause strange things to happen including flame sense issues.
Thanks for letting us know you were helped.
One other thing to keep in mind on older furnaces is the screws that hold the burner in as well as the screws on the control board. Those screws get rusted and loose. Any loss of ground can cause strange things to happen including flame sense issues.
