How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask airheatman Your Own Question
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8049
Experience:  Furnace, A/C and heat pump specialist.
Type Your HVAC Question Here...
airheatman is online now
A new question is answered every 9 seconds

My unit is Trane XV80. TUD080R9V3J1 Heat Mode: Furnace works

Customer Question

My unit is Trane XV80. TUD080R9V3J1Heat Mode: Furnace works fine, fan runs at low speed.Problem:
In AC mode, fan runs at very low speed, not enough to circulate air through coils to cool. The fan used to run at high speed in AC mode.
FYI: Outside AC unit kicks on and cools coils, but I know it will freeze up coils if there is not adequate air flow.The unit uses the Trane Programmable Motor : D341313P04. Mod 00819. It has a wire harness coming from the Intell-Ignition board, 16 white wires.How can I get the fan to operate at high speed when in AC mode ?
Submitted: 8 months ago.
Category: HVAC
Expert:  Tim H. replied 8 months ago.

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need. Please be patient as many times we work with several customers at once.

Did you change any dip switch settings on the board? What position are dip switch settings 1,2,3, and 4 in?

Customer: replied 8 months ago.
Hi Tim, thank you for your reply and help.
- . I have never changed the dip switches.
There are 2 dip switches, the positions are as follows:1. ON. 5. ON
2. OFF. 6. ON
3. ON. 7. OFF
4. OFF. 8. OFFCan you please send the matrix of switch position for desired fan speed for AC mode and Heat mode?Does dip switch "one" control the fan speed in AC mode alone ? What does dip switch"two" control ? Fan speed in Heat mode?
Thank you
Expert:  Tim H. replied 8 months ago.

I've attached a manual. On page 11, it shows cooling dip switch setting. So first you determine the tonnage of outdoor unit, then you set the switch positions as shown for either low, medium or high speed. Dip switch 2 has no special function, it is just part of the total setting for speed.

Customer: replied 8 months ago.
Thank you for the manual. My outside unit is a 2 1/2 ton,. as it is a Trane XE1200, TTP030D100AO
According to the manual, switch setting for Normal operation should be :. OFF. ON. OFF. OFF I'm assuming the manual refers to board dip switch labelled " S3 " ?My board actually has three dip switchesS1. Only a two switch dip:... 2,3
S3. A four switch dip:... 1,2,3,4
S4. A four switch dip:... 5,6,73Does manual refer to Switch 3. "S3" settings?Where is setting chart for Switch 4 ? And Switch 1 ?My Switch S3 is set to On,Off,On,Off .....which is not even listed in manual.Can you give description/diagram of each terminal wire/color connection on the IFC board, as to what they should be connected to? Also, what terminals should be jumpered for operation? My IFC board is :. D341420P01. Rev B.. I believe I have the multi-speed programmable motor, it is D341313P04,. ...Mod 00819My System:.
IFC board terminals:
Blk/Twin, W2, W1, R, G, B/C, Y, Ylo, O......9 terminals total.Wires coming into IFC board from:Thermostat: ....Red, White, Green, Yellow
Outside AC unit,
....- Red, Wht. (I believe start relay)
....- Green, Blue ( I believe Temp sensor)Humidifier Selonoid
......White:. (Goes to 24VAC transformer)I have a 4 wire Hunter Programmable Thermostat about 2 years old.
Expert:  airheatman replied 8 months ago.

My name is ***** ***** a different expert.Your problem is most likely going to be in the bell control on the end of the motor if you have not changed any dip switch stings prior to this conversation.

Issue is either bell control or board but 90 per cent of time it is in bell control.You can not trouble shot these motors with a standard volt meter as the motor is high voltage powered but low or dc voltage controlled,

Testing requires the tool below.

If you want to get this tool I will guide in troubleshooting.

The bell is about 450 bucks if t is out of warranty, so we really need to know before just replacing parts.!2966!3!50916701757!!!g!82128731277!&s_kwcid=AL!2966!3!50916701757!!!g!82128731277!&ef_id=VznGnAAAAG7Thv3w:20160715234927:s

Customer: replied 8 months ago.
I received your response and suggestion, however , you not answer all my questions? If I follow the suggestions of the first expert, my configuration does not make sense. I would have expected to follow that string first. I prefer to go about troubleshooting in a logical manner so I cover all bases. At this time, I will take another avenue for advice. Thanks anyways.
Expert:  airheatman replied 8 months ago.

Totally understand. The proper steps in troubleshooting this issue is to start by attaching the tool described.If you do not have or want to aquire the tool, your best bet is to call in a technician.

AS far as logical troubleshooting the tester mentioned is quickest and best solution.

The fact that you have not changed any settings or dip switches causing the change in operation indicates that either motor controller bell or circuit board is failing.

If you are unsatisfied, we can request a refund of your deposit.

Customer: replied 8 months ago.
Well, let me provide some additional info to explain the reason why I asked for the terminal connections on the IFC board.
- the original multi feature Honeywell thermostat shorted out and needed to be replaced. I replaced with a simple standard 4 wire Hunter Programmable. I don't know if the short on the tstat took out anything on the IFC board...but the furnace seemed to work fine all Winter with new tstat. Again AC compressor starts and cools coils. But fan does not go to high speed.Per my last email, correct wire configuration to IFC board needs to be verified before digging into Motor Bell housing. Thank you.
Expert:  airheatman replied 8 months ago.

Totally understand.

Red from R on Thermostat will go to R with a jumper to BK on Furnace IFC

White from W on Thermostat will go to W1 with a jumper to W2 on Furnace IFC

Green from G on Thermostat will go to G on Furnace IFC

Yellow from Y on thermostat will go to Y/Y2 on Furnace IFC

AS for the humidifier, do you have a separate humidistat?(the 4 wire thermostat does not offer humidity control)

Customer: replied 8 months ago.
Thank you for the Thermostat terminal description. All of these are correctly connected. Yes, there is a Honeywell humidifier on the furnace with a humidity control dial. There is also a temperature sensor outside (two wires) that I'm guessing tells the furnace what stage to be in for heating or cooling depending on outside temp ? Can you see my earlier response in this thread? ( Wires coming from/ going to AC unit outside, temp sensor wires, humidity control wires, ) I have listed all my inputs/outputs that make up the configuration. All these additional wires need to be verified as to proper hookup to the IFC board. Also what jumpers should be installed or removed based on my system described above ( 2 1/2 ton Trane AC Two stage heating/cooling. Thank you

Related HVAC Questions