We have a heat pump for our basement and the inside air handler blower will not stay on.

And the only way I can get the inside blower to even start is to turn off the huge breaker switch next to the unit and then put it back into the on position. The blower will then come on and spin for about 10-15 seconds. An audible "click" will then be heard coming from the small box that the low voltage/wall thermostat wires are connected to and then the blower shuts down.

This happens regardless of whether the thermostat is set to “auto” (calling for cool) or to the “fan-on” position. The only difference is if the thermostat is in the “auto” position, the outside unit fires up and continues to run even after the inside audible "click" is heard and the inside blower shuts off.

Once that audible click is heard and the blower shuts off, it does not matter what I do to the thermostat. The blower will not come on again for the 10-15 second cycle until I shut off and turn on the large breaker next to the air handler.

The blower blades spin freely, the fins are very clean, and when it is running for that 10-15 seconds, it sounds fine and is drawing a lot of air.

Any help is appreciated. It is American Standard by Trane. Thanks.

Exact model number of unit?

Thanks for the reply.

Model; TWV024B140A1
1/4 H.P.
1.7 F.L. AMPS
200-230 VOLTS
American standard, The Trane Company
MFR Date 01/97

Most likely need a new control board, or a new sequencer.

That air handler has a time delay board attached to fan relay. It goes bad on these units. Replace fan Relay.

OR

The trane air handler has the printed circuit board attached to the relay
You have to replace it once it goes bad,or you can by pass the board by
Removing the board from the relay connect green wire to one side of the
Relay's coil and blue wire to the other side of coil disconnect the red
Wire and tape it you will not need it (green wire and blue wire goes in
Place where you disconnected the circuit board.

OR

Buy a new one

Direct Factory Time Delay Relay New Upgraded Model (American Standard Trane): American HVAC Parts

Thanks again for the reply.

However, your post has three solutions. Is solution # 1 and solution # 3 the same. Solution # 1 is basically "Replace fan Relay". Solution # 3 with the link takes me to the American HVAC Parts website for the time delay relay part.

Solution # 2 is Greek to me so that ain't going to happen.

Thanks again. Regards.

Quote:

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Originally Posted by dcw1dcw1

Thanks again for the reply.

However, your post has three solutions. Is solution # 1 and solution # 3 the same. Solution # 1 is basically "Replace fan Relay". Solution # 3 with the link takes me to the American HVAC Parts website for the time delay relay part.

Solution # 2 is Greek to me so that ain't going to happen.

Thanks again. Regards.

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Solution one tells you to replace the relay

Solution 3 tells you where you can buy the relay.

They are not the same. LOL

Solution 2 tells you how to eliminate the relay so you do not have to buy one.

OK. I'll give that a shot. One last question before I start. We had some painting done a while ago and I believe they removed the entire thermostat from the wall. Is it possible that the problem I have described (blower only coming on for 10-15 seconds) is the result of the low voltage wires being reconnected incorrectly to the air handler?

Thanks again. Regards.

Quote:

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Originally Posted by dcw1dcw1

OK. I'll give that a shot. One last question before I start. We had some painting done a while ago and I believe they removed the entire thermostat from the wall. Is it possible that the problem I have described (blower only coming on for 10-15 seconds) is the result of the low voltage wires being reconnected incorrectly to the air handler?

Thanks again. Regards.

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Anything is possible but the only way to be sure is to check the wiring.

I replaced the time delay relay using part # REL2708A and no change. Actually, the blower now does not come on as the "click" is heard right away as soon as I turn the power back on. The blower does not spin for the 10-15 seconds. Whereas with the old relay switch, the blower would run for about 10-15 seconds upon me turning the breaker back on and then I would hear a "click" and it would shut down. After replacing the relay switch, the outside unit (heat pump) still fires up when the thermostat calls for cool but no blower fan comes on. Just that same "click" when I throw the breaker switch back on.

I disconnected the red and white wires from the thermostat and tied them together and still same thing, no blower fan. I assume the red and white were what I was to tie together to get the system to run and bypass the wall thermostat.

After the "click" is heard from the relay switch, and the blower shuts off (or now does not even start turning) the blower motor still does not get hot. It looks like there is a capacitor on the blower and I have tried to get the blower blades started with a flick of a screwdriver hoping it was the capacitor. But it does not seem like the blower motor is getting any power. Something is causing that relay switch to trip and keep the blower from running.

Is there any way I can bypass all thermostat wiring and test the blower motor. Can I bypass most of the other wiring to do the same—basically test the blower fan and motor? Or could this be a hardware issue rather than a wiring problem?

Anyway, any thoughts or help would be appreciated.

If its wired according to rule of thumb,, you should tie the red and green to see if the blower will work,, tieing the red-white-green together should make furnice come on and the blower work

Thanks for the reply but I need some clarification. You say "tie the red and green to see if the blower will work,,,,,,,tieing the red-white-green together".

First, where am I doing this--at the thermostat, at the relay switch, at the low voltage wires at the air handler?

Secondly, you say tie the red and white which is two wires but then you say the red, green and white which is three wires. Am I performing two different tests or is it the same test? I already did the red and the white at the thermostat and no difference. Should adding the green to that make any difference? Thanks.

Thanks for the reply but I need some clarification. You say "tie the red and green to see if the blower will work,,,,,,,tieing the red-white-green together".

First, where am I doing this--at the thermostat, at the relay switch, at the low voltage wires at the air handler?

Secondly, you say tie the red and white which is two wires but then you say the red, green and white which is three wires. Am I performing two different tests or is it the same test? I already did the red and the white at the thermostat and no difference. Should adding the green to that make any difference? Thanks.

Thanks for the reply but I need some clarification. You say "tie the red and green to see if the blower will work,,,,,,,tieing the red-white-green together".

First, where am I doing this--at the thermostat, at the relay switch, at the low voltage wi

Sorry for the double post.

Anyway, I have a little more information but it may not be worth much.

When I turn the breaker back on and if the thermostat has everything in the “OFF� position (no call for cool/fan in off), I hear that audible click immediately.

When I turn the breaker back on and if the thermostat has no call for cool BUT the FAN is in the "ON" position, the fan will spin for about 1 second and then I hear that audible click and it shuts down. The fan blades actually do start spinning.

So it would seem I have connected the new relay switch properly as it is doing exactly as before except I get shut down on the blower after 1 second instead of the 10-15 seconds with the old relay.

Again, the outside unit fires up with a call for "COOL" and I can hear the freon (or whatever it is) begin coursing through the system. But no blower.

No sparks, no unusual smells, no breakers tripping---just the blower fan will not stay on.

Have you changed the thermostat on this unit?

According to your first complaint/problem you board should have been defective.

You can try to power the motor direct if you know what you are doing with the wiring. At least this will tell you if the motor and or capacitor is defective.

You can jump a wire from the red to green and the indoor blower should come on and run.

Success!! Tried jumping but still nothing. So I assume that tells me that the thermostat is not the problem. From the answers, it was looking like a wiring problem at the air handler. Basically, looking at those wires I see a spider's web. This was not heading me in the direction I wanted to go. Switching out hardware parts and reconnecting the wires to the same spots is one thing. But looking at a schematic and having someone ask me how many volts, ohms, watts, amps, protons, and neutrons I am measuring at a certain connection is another. Or asking me if the hot wire is connected to the energizing coupler on the negative side of the capacitor or connected in series through the proton port adapter... That is Greek.

So, I followed the green wire from the thermostat back to the air handler where it connects to the box. On the other side of the cover where the green thermostat wire should connect to the green wire inside the box, there was nothing! The thick green wire inside the box was connected to the clip next to the one that the 12 volt thermostat wire was on.

So, I moved the green 12-volt wire over to pair it with the thick green wire on the other side and voilà, the fan fires up and runs. Call to cool brings on the outside unit and it is blowing cool air. I haven't turned it off yet but I think I'll let it run for about 30 minutes. Thus, it seems it was a wiring problem at the air handler.

Also, I got the relay switch (# REL2708A) on eBay for $12 brand new with free shipping.

Thanks for all the posts as they were very helpful and got me pointed in the right direction.

Regards