blower motor stays on all the time/even w/ unite is turned off


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Old 01-08-03, 08:41 PM
david ahluwalia
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Question blower motor stays on all the time/even w/ unite is turned off

Hey I have a Trane heat pump,1997 yr mdel TWV025B14oAI.I recently nticed that the fan was staying on.I turned the heat down and the fan stayed on.I turned the unit off from the thermostat and the fan still stayed on,The heat works its just w/ the temp is reached the fan just stays running ,.What wuould keep the fan on?Please .I f anybody has a diagnostic tree I can follow.?
 
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Old 01-09-03, 05:22 AM
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I don't have a diagnostic tree but I'll give you a few things to check. On some thermostats, even with the switch set to off, I think the fan ON position will run the fan. Check that first. Next, look at the terminals on the thermostat and make sure that the Green wire and the Red wire are not touching somehow. If not, take the door off of the air handler and get at the low voltage electrical connection. Take off the Green wire and see if the blower stops. Let us know what happens.
 
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Old 01-09-03, 07:56 AM
bigjohn
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Thermostat fan switch is in AUTO? A lot of the Trane units have a blower relay with an OFF time delay. Look at the blower relay. Does it have a small solid state board attached to it? If so, that is the OFF time delay. Often, when they malfunction, the time delay stops shutting the fan off.
 
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Old 01-09-03, 08:31 AM
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Good point bigjohn, that has baffled me for a few years. Why does a manufacturer install such a troublesome piece of junk in the first place? Rheem does that also and it must get them a .0001% higher efficiency rating if they blow that last 15 seconds of cool air to the house. Unfortunately, it costs the customer $50 or more to have someone remove the thing a few years later.

If it is in the low voltage circuit only, you can bypass it with no problem at all. I can't remember the exact configuration but if you can't figue it out, reply with the terminal designations and wire colors on the delay board and one of us will tell you how to get around it.
 
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Old 01-09-03, 05:56 PM
bigjohn
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I remember looking at some specs for some residential systems one time and the only difference between 12 and 13 SEER was a blower time delay relay. ICM makes generic replacements that I know Johnstone Supply carries. Trane would charge an arm & a leg for that relay. Matter of fact, ICM is a good catalog to have.

www.icmcontrols.com

They make a lot of items we use in the trade, like delay timers, heat pump defrost boards, phase monitors- lotsa stuff. Great website too.
 
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Old 01-09-03, 08:20 PM
david ahluwalia
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RE fan delay

Hey,guy I think your on to somthing.I does have a small board on a fan delay relay.I think I eliminated a switch or t-stat problem by discinecting the T-stat and the fan stays on.I will probly looki at locating a new one.But I would be interested in poss bypassing for test prposes. Here are the terminals...#1 red (small gauge from power source)#red (large gauge 12?) #4 light blue 2wires together.#5red small spliced to transfomer and to somthing from the T-stat.#6white theres another light blue 2 wire terminal conected on the board next to sme small cylinder looking compasiter(poss)& a green wire on the other side of that .Does any of this sound familar?Thanks for your help
 
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Old 01-09-03, 11:33 PM
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Look at the web site that bigjohn mentioned above. You can find a replacement there that will probably cost much less than OEM.

You can't bypass the delay if the blower relay is also on the board and I think from your description it is.
 
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Old 01-10-03, 05:46 PM
david ahluwalia
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re blower relay

I forgot to mentsion that the board looks like it does detach from the relay.There are 2 terminals sticking out of the side of the relay.The board is attached here.One teminal (male&female spade connections)has some solder.Maybe running a jumper between the termimals
 
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Old 01-10-03, 08:33 PM
bigjohn
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Hi david:

I don't believe I would do the jumper. At this juncture, we don't know if the board is keeping the relay energized or if the relay contact points are stuck closed. Look at the relay and see if you can tell which terminals are for the magnetic coil and which are for the contacts which would be the wires that go to the fan motor. Turn off the t-stat but have the power on for the air handler. If you have 24 volts at the magnetic coil temrinals, then the circuit board is bad, but if you don't and the fan is running, then the contact points are stuck closed. It's somewhat of a moot point because the whole thing has to be repalced anyway. You have the choice of just installing a standard fan relay or getting a new delay type. If it were mine, I would go back with the delay type because that's how Trane intended it to work. Look around in the air handler, Trane usually supplies a document called Service Facts which contains a parts list.
 
 

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