Heater Will Not Come On

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Old 11-23-15, 02:54 PM
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Heater Will Not Come On

Hello,

My heater will not come on and I was wondering if there was anything easy I could check before calling for service. I noticed a couple of nights ago it did not come on as it got down to about 60 in the house with the temperature setting set at 65 as it was the first cold spell of the year and got down to the high 30's or low 40's.

When I set the thermostat for a warmer temperature than what it is showing inside, I can hear the thermostat "click" and can see "Heater On" displayed on the thermostat. After a minute or so, I can hear the compressor outside turn on as I hear the fan come on for just a few seconds and then it cuts off. I have checked the breakers outside and inside, they are all good.

Could it be one of the run/start capacitors outside? My compressor outside is a Trane XL14i, M/N: 4TWX4042A1000AB, Mfr. Date: 10/2004. The air handler in the attic says American Standard, Inc, The Trane Company, Mfr Date: 4/2005, Mod No. 4TEE3F49A1000AB.

Thanks.
 
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Old 11-23-15, 03:45 PM
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Are you talking about the fan on top of the heat pump that shuts off?
 
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Old 11-23-15, 06:07 PM
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It sounds like he thinks everything on the condenser is coming on... Notice "I can hear the compressor outside turn on as I hear the fan come on for just a few seconds and then it cuts off." It doesn't read as though Greg has actually gone out to look.

I know when I had problems with my AC compressor a while back, I thought I heard everything starting up, but when I went out to check, the condenser was running because I could hear it hum, but the fan wasn't spinning..

BTW assuming everything starts up then shuts down, could it be a a refrigerant issue or would it not start up at all if it was to low?
 
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Old 11-23-15, 07:57 PM
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Yes, the fan on top of the heat pump outside comes on only for a few seconds, then shuts off. When I turn it on, by time I run out there is about when it comes on and then turns right off. I can hear a slight humming sound if I put my ear up to it, but yet, if I go set the thermostat to a higher temperature than what it is in the house, I can no longer hear the humming.

Maybe it is my fan motor that has gone bad. I replaced it this summer as it had gone bad. I was not able to find exactly the same fan motor, but Grainger sold me what they called a direct replacement. My wife had an AC guy come do a service pm on it anyway and he noticed it was not the same motor that normally comes with the unit, but said it seems to work fine. He said it was a variable speed motor, but that our unit does not normally have a variable speed motor, if I am remembering the details correctly. I believe he said that it should work fine for the summer, but we might have problems with it during the winter. I wonder if this is what he was talking about.
 
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Old 11-24-15, 08:11 AM
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I think what your talking about is a multi speed motor. If the motor worked OK in cooling it should work in heating mode. Might be the defrost module acting up.
 
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Old 11-24-15, 12:25 PM
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Yeah, I looked at my last invoice from when the repair man worked on it this last summer. He actually wrote on the invoice that "the fan had been replaced with a single speed fan motor on a 2-speed system, had to rewire to single speed off of the main contactor and add a run cap". So, I had it backwards. I said previously I went from a single speed to a variable speed when I actually went from a 2-speed to a single speed.

I did not understand that because after I initially installed the new motor, the unit cooled down fine, but it stopped working some point later while I was at work, so my wife called the repair man.

The wiring colors did not match the one that came off. I probably need to find a different place than Grainger to get parts because I entered the exact info from the motor and then asked my wife to go get it while I took the system apart. She came back with the single speed motor saying that Grainger said it was an exact replacement. Now, my notes about the one I removed initially are long gone, so I don't have any idea what the part number is of the one that should be in there. Anyway, I'm going to take it apart and look for bulging caps or blinking boards and go from there.

Thanks.
 
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Old 11-24-15, 01:21 PM
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I looked inside the condensor/compressor unit outside and did not find any bulging caps. Apparently, the defrost module & system have frequent problems because there was a whole page, front and back, in the service envelope in there for troubleshooting the defrost cycle based on the LED blinking on the board. Based on that, everything is OK with the defrost system because the LED was blinking green about one time per second. Looking at the contactor though, it looks like there might be a problem there as it has what looks like a burnt spot where the actual contact is made, not sure if that is normal wear and tear or not. Am sending pictures, please see links below. The fact that I heard the fan motor come on for a few seconds tells me though that that probably is not the problem. Another interesting thing is that when I pulled the power disconnect that is next to the condensor/compressor, I noticed the LED was still blinking.
http://s1115.photobucket.com/user/gh...g.html?filters[user]=124940105&filters[recent]=1&sort=1&o=0
http://s1115.photobucket.com/user/gh...g.html?filters[user]=124940105&filters[recent]=1&sort=1&o=1
 
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Old 11-24-15, 02:01 PM
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Do you have amp meter? If so, you need to check to see what kind of amps the unit is drawing and if you're contactor is getting power and/or even if it's working correctly... If you think about it, it could be your t-stat, not that I've every heard of it happening, where it sends power to start the unit, but then it drops power...


Have you tried pressing the contactor down to see if it will run? If manually pressing the contactor down .. and it stays running you know it's either the power dropping out of the contactor or it's just bad...

Just remember, you'll need to be super careful when messing with anything electrical.. It could kill you!

Oh.. there are also tons of youtube videos on how to test these parts... The issue is going to be if you have the tools to check them...
 
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Old 11-24-15, 03:08 PM
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No, I do not have an amp meter. I need to buy one. I have a good volt meter. I have a feeling that the blower motor is not working in the air handler in the attic. Could either be because the motor is bad or it is not being told to come on. Take a look at my notes.

Pulled the cover on unit outside, green LED on board is blinking about once per second as sheet says it should that was in service envelope in unit.
I pulled the disconnect to reset power to unit outside, did notice though that the green LED continued to blink.
Also noted that the contacts have a lot of arc marcs on them, see pictures at posting listed below.
http://www.doityourself.com/forum/he...ml#post2482885
Re-installed the power disconnect outside and went inside and adjusted thermostat for setpoint a couple of degrees higher than what the temperature was in the house. Thermostat made an audible click and displayed “Aux Heat”. The fan outside came on and stayed on for about 5 minutes and turned off. Never saw any increase in temperature in house, nor did I ever feel any air being blown from vents in house. Then, I noticed a click on thermostat and saw the display chage from “Aux Heat” to just “Heat On”. Fan came on again, this time only for about 5-10 seconds and turned off. Still no change in temperature in house, nor any air being blown from vents. I changed the setting on thermostat to “Emergency Heat”, I noticed a red LED solidly lit in upper right-hand corner of thermostat, although the actual display on thermostat said “Heat On” rather than “Aux Heat” as I would have expected. Still no change in temperature in house and no air being blown from vents in ceiling. I switched the thermostat back to Heat, went up in attic, can hear a slight humming sound coming from air handler, could just be normal sound of electricity going through it. Turned off system via the thermostat. Pulled the filter. Could feel significant heat coming from inside air handler from the left side of filter, this could have been from when had set for Emergency Heat. Also noted that bare copper line that goes from outside condensor/compressor to air handler in attic was almost too hot to touch.
 
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Old 11-24-15, 05:28 PM
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So you're saying your blower motor doesn't seem to be running...

What happens when turn the fan on by it self from the thermostat? I'm assuming the fan won't run..

You need to start eliminating possible problems like t-state, board, motor and even the wire that runs from the t-stat to the air handler.

I can tell you what I would do, but Houston or one of the other guys here should be able to walk you though every step of trouble shooting the blower fan... These guys are really good and can tell you even what wires to jump to see if the fan runs.. I can tell you what I would check, but I couldn't tell you which wires to check like these guys can...

Keep your fingers crossed for Houston or one of the other Pros to walk you though the trouble shooting process... They're really good!
 
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Old 11-25-15, 04:50 PM
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Yeah, the blower motor does not run. I called a service tech to come out and they said it was the control module that mounts on top of the blower motor in the air handling unit in my attic. It cost me $80 for them to come out, but they said it would cost $708 parts and labor to replace the control module, which they would have to order and could not install till next Monday.

I looked it up online and found where I could get the part for $320 and it only takes about 5 minutes to install. Problem is, I did not really see any advanced troubleshooting going on in making the determination that it definitely is the control module. The technician said that usually the resistor burns up that is mounted in the middle of the board that is in the control module, but there was nothing visibly wrong with the resistor. They verified the blower motor was not seized. You could see a place inside the control module where it looked like it got hot as the outer cover became discolored where it would have been close to the components within.

The place I called for the part said I should get it this Saturday and I am also getting the repair kit, which is just the resistor, and I also ordered the inline surge protector, since this control module usually gets taken out from a power surge as they explained it. My plan is to try to repair the module and if that works, then send the new module back to them. If the repair does not work, then will install the module. If that does not work, it would be like going to Vegas and putting $350 down on the blackjack table, which I never do because I am too cheap.

It would be nice to know how to jumper out the motor, because if I could force the motor to turn on, I guess that would eliminate the motor as being bad. The guy I called to order the part said initially to measure the windings of the motor and that they should all be about 10 ohms and that if one motor winding measured about 4 ohms, the motor was probably bad. I measured them and got 4.8-4.9 ohms on all 3 windings. I told him my measurements and he said that since they were all the same reading, he felt like the motor was good, so I ordered the control module. There is also a control board which feeds a bunch of signals to the motor, hopefully there is nothing wrong with the control board.
 
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Old 11-28-15, 06:11 PM
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Okay, received my new air handler blower motor module this morning. Pretty good since I ordered it at 4 pm Wednesday afternoon and came from Boca Raton, Florida.

Unfortunately though, I installed it and it did not fix my problem. Oh well, if I would have went to Vegas, I'm pretty sure I would have spent more than $365 anyway. I probably should have gone ahead and paid the service folks the $708 because they said if the module did not fix it, they would not charge me anymore.

Does anybody know how to jumper out the blower motor and force it to come on? It is not seized up and all 3 windings measure the same at about 4.8 ohms. The heat pump fan comes on outside, then I hear a click and can see the glow from the resistive elements turning on in the air handler in the attic. The blower just never turns on.
 
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Old 11-28-15, 06:27 PM
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First thing first..... don't allow the heat coils to run with no blower.

That is a variable speed ECM motor.

What part did you order and replace ?? The board INSIDE the motor ?
That board is programmed to work with each air handler it's installed in.
 
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Old 11-29-15, 08:25 AM
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Here's a link into a set of articles on troubleshooting ECM motors ... perhaps they might be useful to you.


York central tech talk /2012/09/14/ECM-motor-troubleshooting-part-1
 

Last edited by PJmax; 11-29-15 at 10:31 AM. Reason: changed link text
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Old 11-29-15, 10:33 AM
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Thanks for posting that dsomerv..... your link was fine. I just changed the wording to make it easier to read as the board shortens the URL's.
 
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Old 12-03-15, 10:03 AM
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dsomerv, thank you for the articles, I scanned over all 3 parts and that is very detailed and I will try to go through it when I get the chance. Is that Trane specific?

PJmax,
Will try to answer your questions and address your comments. I have not let the heat coils run without the blower except to troubleshoot and when doing that, they did not run for more than about 5 minutes. Is that too long, would it mess something up and how?

The module I installed was MOD02234 which replaced MOD00944, this is for the Trane air handler 4TEE3F49A1000AB. What do you mean exactly on "the board inside the motor"? When I bought the part from Airstar Supply, I gave them all of the info for my system and they made sure it was programmed correctly they said.

I had another HVAC technician come out and he is saying it is usually the module, not the motor, and since I have already worked on the system myself, I am getting dogged about that and of course the $365 module I installed is the suspect part in question. He suggested calling the place I ordered it from and tell them my technician thinks it is bad and hopefully they will have me send it back to them and maybe send me another one. I'm not sure if they will go for that or not. Looking at the article that dsomerv sent, the 4 things listed as probable causes at the beginning of section #1, well, the first two did not have anything to do with bad module or motor, so I need to take a more detailed long look at that article when I have time and hope I can do so before it gets too cold, just staying busy working my job.
 
 

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