Heating, Air Conditioning, Fridge, HVAC/Airflow issues

Advertisement


Question
Let me start by saying what my furnace and A/C are and then describe my issue.

I have both a Carrier Furnace and A/C. Furnace is a Carrier; Product Number: 58MCB100---11116 and Model # 58MCB100-16, A/C is model # 24ABA

I have a 2 story home built in 2007 with 2122 sq ft (Not including unfinished basement. It has 16 floor registers (8 on upper floor, 8 on lower floor) and 6 return air (3 on each floor)

Last summer I was investigating my common issue of having less air flow coming from my 2nd floor registers as most people do.

I opened my panel on my furnace and checked my furnace wires to see were the original HVAC installer had them installed.  

They had the Black "HI" hooked up to the A/C and the RED "MED LO" to the HEAT. I moved the Yellow "MED HI" to the HEAT.

I Turned the Furnace back on and it sparked and blew the fuse.

I checked and the Yellow and Black wire connectors and seen they touched a little.

I moved the wires to make sure the connectors didn't touch, put a new fuse in and turned the furnace back on. No problem.

Here's the problem. Every since the spark, I noticed an issue.

I have a Honeywell RTH7500D thermostat, and when I press the up arrow to turn the heat higher it blinks "COOL" and vise versa, if I call for A/C it blinks "HEAT".

The furnace will heat and cool normal TO A POINT. What I mean is, the blower speed seems to be reversed somehow.

I got out my Extech AN100 anemometer and checked the CFM coming out of all my registers in both the Heating and Cooling mode.

My unit has more CFM coming out in the heating mode, then the cooling mode?

I don't understand because it should have more in the cooling mode, since the Black wire (HI) is set to COOL and the Yellow wire (MED HI) is set to HEAT.

My upstairs avg out of the floor registers in heat mode is;  441.875 cfm and in cool mode; 409.15 cfm

My downstairs avg out of the floor registers in heat mode is;  574.575 cfm and in cool mode; 567.78 cfm

When I had the sparking incident, I guess it messed something up. The unit still heats and cools, but the thermostat saying cool when its heating and heat when its cooling is strange.

I am a novice when it comes to HVAC, I do not know much about it.

What could be the problem?

Any help would be great, Thank You.

Answer
To start with, the amount of registers, returns and CFM's is meaningless in the context of this question.  In order for that to make any sense, the cooling and heating requirements have to be known.  The amount of floors and square footage is just not enough.

"I have a Honeywell RTH7500D thermostat, and when I press the up arrow to turn the heat higher it blinks "COOL" and vise versa, if I call for A/C it blinks "HEAT"."
  I do not think I have ever seen this happen before as you describe. That is not to say that there is nothing wrong.  Follow the link and check the settings or contact Honeywell for more help.  (http://yourhome.honeywell.com/home/Products/Thermostats/7-Day-Programmable/RTH75)

It is possible the control board in the furnace was damaged when you shorted the wires.  It is also possible there is something wrong with the fan motor.  The only way to determine what is actually happening is to test the control board with a meter.

Craig  

Heating, Air Conditioning, Fridge, HVAC

All Answers


Answers by Expert:


Ask Experts

Volunteer


Craig HVAC Expert

Expertise

I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.

Experience

I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

Education/Credentials
5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

©2016 About.com. All rights reserved.