# Air Handler Won't Stop Running, Help Please!!!



## Ralph III (Oct 7, 2011)

Hello,
I replaced two "frozen" 60amp built-in air handler breakers on our attic unit and upon turning it back on, the air handler blower won't stop running? The outside condenser cycles on and off as normal, so we have air, but the blower won't stop running? 


1) I tried various settings at the thermostat, including turning it to the "off" position, but still the air handler wouldn't stop running. I then removed all the wires from the thermostat but the air handler continued to run.


2) I turned the main outdoor breaker for the air conditioner to "off" and then back "on", in hopes of possibly resetting something, but accomplished nothing. 


*Apparently a contact or switch of some sort is stuck on the air handler? I read a thread stating a "Fan/Control Relay" can do this? Does that seem most likely and is that the unit, with five wires attached, which is directly under the breakers as pictured below? *


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You may not need these details but just FYI. It's a split system RUUD ac with heat strip, UBHA-21J-14SFBAI.



I was sure I replaced all wires as they were originally installed. The air handler breakers had two #12 wires each (oranges/blacks) in each lug, with exception the top breaker had an additional (orange and black) #14 wire installed in the lugs. So the top breaker had three wires (two #12 and one #14) in each lug. 


Upon replacement, I twisted these wires together and inserted them as one into each respective lug. They flattened nicely and have made solid contact.


The orange #14 is spliced with one leg going up to the transformer and the other leg going down to the capacitor. The black #14 is spliced with one leg going up to the transformer and the other leg going down to what I beleive is the Fan Relay?

I note this because I am not absolutely positive the orange wire was attached to the breaker, though 98% sure. There was so much corrossion the breakers broke apart upon trying to remove them. The three black wires were all tie wired together but I found the orange #14 wire dangling by itself but beside the other two orange wires, which were tie wire together. This is how it appears in my original pics as well.


*Any help would be appreciated!!!*


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## amnayray (Mar 23, 2012)

once the airhandler is energised it keep running,no thermostat wire connected


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## ggold (Mar 19, 2012)

Before you start beating your head against the wall, How long did you wait after disconnecting all the low voltage wires for blower to stop running ? some units have time delays and will continue to run *up to 90 sec*. after.


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## Ralph III (Oct 7, 2011)

Thanks for the replies!

1) I've disconnected the thermostat wires(at the thermostat) several times and have also turned it to the "off" position for more than 10 minutes each time. It cycles the outdoor condenser normally but will not shut down the indoor air handler blower.

2) I've also had the main breakers turned off for up to an hour at a time. The blower starts immediately upon turning the breaker back on, no matter what setting the thermostat has.

3) I went ahead and replaced the "power relay" module, otherwise fan/control relay (5 terminal) module, with a brand new one but still the blower will not stop running?

*I need some input/suggestions with this one guys. I'm not an ac guy, so if I need to test the blower or anything else for a short please be specific.*


Thanks, Ralph


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## mpnret (Nov 11, 2010)

Was the air handler working properly before you replaced the breakers? I am not totally sure what "frozen" breakers meant.


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## Ralph III (Oct 7, 2011)

mpnret said:


> Was the air handler working properly before you replaced the breakers? I am not totally sure what "frozen" breakers meant.


Yes, everything was working properly with exception of the two 60amp built-in air handler breakers. 

The unit and electrical components are quite corroded from moisture/condensation thru the years. The breakers were "frozen" in that you couldn't turn them on/off much less offer protection with a short. The breaker lugs were also quite corroded which resulted in damage to the old breakers upon removing them.

I feared it could present a fire hazard, so I replaced the two built-in 60amp breakers with two new and exact matches. Upon powering the ac back up, via main breaker, the air handler won't now shut off. 

Ralph


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## ggold (Mar 19, 2012)

Did you replace relay ?


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## Ralph III (Oct 7, 2011)

ggold said:


> Did you replace relay ?


Yes, as noted in previous post today. I replaced the relay with a brand new one today but it made no difference. The air handler is running like a
J-Deer (non stop)....

The thermostat apparently isn't the problem nor the relay, so what else could it be? It is a very simple unit, as seen in pics, with no fancy electronics.

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I checked the continuity on breaker lugs/wires while unit was powered down. 

A) The bottom breaker lugs and respective wires have no continuity. The blacks and orange wires feed various components as seen in photos. 

B) However, the top breaker orange and black wires do show continuity between them(thus breaker lugs also) and everything they run to? Is this normal to have continuity showing between two different 120amp legs of a 240vold dp breaker?

C) Also, if I remove the orange #14 wire from the top breaker (top lug) the air handler will shut off with that, but not come on. That wire branches(see wire nut) with one wire going to the transformer and another wire going to the capacitor.
Ralph


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## mpnret (Nov 11, 2010)

Ralph III said:


> Yes, everything was working properly with exception of the two 60amp built-in air handler breakers.
> 
> The unit and electrical components are quite corroded from moisture/condensation thru the years. The breakers were "frozen" in that you couldn't turn them on/off much less offer protection with a short. The breaker lugs were also quite corroded which resulted in damage to the old breakers upon removing them.
> 
> ...


I can't offer much in the way of A/C experience, but just using basic troubleshooting skills, based on the info you provided it sure sounds like you connected something wrong. It's too late to say it now but you should have snapped a picture first. Hopefully someone with more experience can shed some light on this.


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## ggold (Mar 19, 2012)

Check your wiring of relay. You should have a wiring diagram on one of your panels.


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## hvac5646 (May 1, 2011)

lol...open mic night:yes:


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## Ralph III (Oct 7, 2011)

Hello All,
I did take photos before doing anything in addition to making notes as needed. The pictures displayed on this thread *are* the original ones BEFORE replacing the breakers. 

The only question in regards to wiring, is whether the orange #14 gauge wire was indeed connected to the top breakers' top lug. That lug was so corroded the breaker broke apart when I attempted to unscrew it. After removing the breaker I found the 14gauge orange wire. It wasn't tie-wired with the other two orange wires but was beside them. There is just nothing else it could have been connected too as the wire is short?

The original photos appear to confirm there was a 14 gauge orange wire attached to the top lug and a black 14 gauge wire attached to the bottom lug (both on top breaker). 

Ralph


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## biggles (Jan 1, 2008)

you have a FAN RELAY does that react to having its 24V wire pulled off the terminal for the coil? thats a 208V/230V air handler sounds like the motor is wired direct from those breakers.


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## Ralph III (Oct 7, 2011)

biggles said:


> you have a FAN RELAY does that react to having its 24V wire pulled off the terminal for the coil? thats a 208V/230V air handler sounds like the motor is wired direct from those breakers.


Thanks biggles.

Yes, that is the conclusion my Dad and I are coming to. That blower has to be direct wired now.

The orange wire(14 gauge) is spliced in two parts; one part runs up to the transformer and another part runs down to the capacitor. So it is supplying one leg (120volt) direct power to the blower. There is no interuptor for that.

The black wire(14 gauge) is spliced in two parts also; one part runs up to the transformer and another part runs down to the relay. So there is an interuption of power capable there from the thermostat.

*Grasping at notions: Is it possible one of the built in breakers became defective so the previous owner/contractor just rigged the wiring? Then when I replaced it with a good breaker, that messed up his rigging and now has direct power?* 

I am about to go into the attic now to pull some wires one at a time, including 24volt, to see what it does.


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## Ralph III (Oct 7, 2011)

Ok, here's what happens with removing wires (one at a time) on relay.


terminal

1 = The blower continues to run no matter if wire is removed. This is the green tstat wire.

3 = Same as above. This brown wire runs to the terminal above m7 on the sequencer(upside down part), which is to the left of breakers.

2 = Same as above. This black wire splits(wire nutted at top), with one part going to breaker and one part going up to the transformer. 

4 = The blower won't run if removed. This wire runs directly to the blower from relay.

5 = The blower can be controlled at the thermostat if this wire is removed. It *appears* to function normally if I remove this wire but only tested quickly. It will turn blower on/off at thermostat and appears to cycle ac, when set to ac. I only tested quickly though. This wire runs to m1 on the sequencer.

Ralph


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## Missouri Bound (Apr 9, 2011)

Pictures are great. No schematic on the door panel? If the blower operated correctly before you changed out the breakers, and does not now you apparently wired something differently or disturbed an existing circuit. When you disconnected the thermostat the blower should have stopped unless the relay is stuck or the blower is wired wrong. No other solution.


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## Ralph III (Oct 7, 2011)

Missouri Bound said:


> Pictures are great. No schematic on the door panel? If the blower operated correctly before you changed out the breakers, and does not now you apparently wired something differently or disturbed an existing circuit. When you disconnected the thermostat the blower should have stopped unless the relay is stuck or the blower is wired wrong. No other solution.


I'm away at the moment but will post a pic of the schematic tonight or tomorrow.

Honestly, I'm completely baffled Missouri Bound. The only thing I changed was the two breakers. There were three wires (oranges) going to top lug on top breaker, there were three wires(blacks) going to bottom lug on top breaker. There were two wires (oranges and blacks) going to each respective lug on the bottom breaker. 

Not that it matters but they were arranged oranges, blacks, oranges, blacks but I did maintain that order. 

There is just nowhere else those wires could have been attached and as appears in original photo.

I just don't know. Is there anything to the fact if I remove the wire from the #5 terminal that it then seems to operate correctly in ac mode? I don't know about heat mode.....

Ralph


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## Missouri Bound (Apr 9, 2011)

It's a matter of troubleshooting, and it's nothing to worry about. A schematic will help and myself or others will help you diagnose this. You're not the first one this happened to or will you be the last. Did you say if this problem existed before you changed the breakers?


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## Ralph III (Oct 7, 2011)

Missouri Bound said:


> It's a matter of troubleshooting, and it's nothing to worry about. A schematic will help and myself or others will help you diagnose this. You're not the first one this happened to or will you be the last. Did you say if this problem existed before you changed the breakers?


No, the ac/heat system was functioning perfectly before the breaker change out. I've included pics of the schematics below.


Please note the following:

In trouble shooting the wires on the Relay, I discovered the following.

A) If I remove the wire to terminal #5 the air conditioning and blower THEN functions correctly!! The ac will cycle normally in "ac" mode, I can turn the system "off", I can also start the blower alone with the thermostat "fan" control. *ALL AS* *NORMAL, in AC mode*. 

That #5 Relay wire runs to the sequencer and is noted online as being the "low motor speed for heater". The #2 is noted as being "high motor speed for ac".

B) With that wire removed from #5 and in HEAT mode, the fan will come on as normal but apparently the heat strip isn't working. I can feel no heat from the vents and the blower case isn't warming up as I'd expect.

This is the kicker. As I recall, when I first started the system back up (after replacing breakers) I recall noticing the air didn't seem warm at that time either, when testing in HEAT mode. I just kind of blew that off for various reasons, mostly because I quickly came to realize the blower was stuck running.

*Is it possible the sequencer is causing the issue at this point? Maybe the jolt of powering it back up damaged it? Again, the ac works perfectly when the #5 relay wire (low motor speed for heater) is removed.*


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## Doc Holliday (Mar 12, 2011)

Quit feeding the fan a constant 24 volts and you'll resolve your issue.. Not at the stat, at the air handler. duh.


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## Ralph III (Oct 7, 2011)

Doc Holliday said:


> Quit feeding the fan a constant 24 volts and you'll resolve your issue.. Not at the stat, at the air handler. duh.


Ummm, can you be a little more helpfull than that as I'm not an ac technician?

*If that is the issue, what is causing it to be fed with 24volt power constantly? 

*What do you see that can be done to correct that or to troubleshoot such?

Thanks, Ralph 

P.S. I left the wire off the #5 Relay terminal overnight and the ac and blower functions properly with that. That apparently dissables the heat strip but it's possible it might have developed an issue after the breaker changeout? Everything functioned perfectly before....


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## Houston204 (Oct 18, 2009)

#5 is a normally closed circuit to the sequencer.
You will need to replace the heat sequencer.


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## Ralph III (Oct 7, 2011)

Houston204 said:


> #5 is a normally closed circuit to the sequencer.
> You will need to replace the heat sequencer.


Houston when I think "closed" I think power flowing to it or engaged. When I think "open" I think no power flowing to it otherwise not engaged due to open circuit.

Just for clarity sake. You're saying it should not be engaged normally, or at least not in ac mode, so it must be stuck? 

I can find a sequencer for the unit but everything I come across only shows the top (upright) portion like *this *unit. What about the upside down part which is attached to the bottom and labeled m5, m6, m7, m8?, as seen in photo below. Where do I get that part from and does it need to be replaced also?

BTW, two wires run from the Relay to the Sequencer assembly as I've depicted below. THANKS FOR ALL THE HELP GUYS! 

RALPH


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## Missouri Bound (Apr 9, 2011)

Ralph III...have you tried here?


HVAC Parts Outlet


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## Houston204 (Oct 18, 2009)

> Houston when I think "closed" I think power flowing to it or engaged.


That set of contacts (4 to 5) on the relay are normally closed but the contacts are normally open on the sequencer (other end of 5). 

If the fan functions correctly with 5 removed, it points to the sequencer.
If the sequencer does not have 24VAC at it's base when this problem occurs it should be replaced.


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## Ralph III (Oct 7, 2011)

NEW DETAILS. 

NOTE: I've kept the wire off of the #5 Relay (runs to M1 on Sequencer) because everything in a/c mode then functions properly. See pic above. 

However, I just discovered after the ac mode cycles and the fan shuts down, the heat strip itself immediately turns on. There is no fan, it is just heating the air handler unbenounced. When a/c kicks on again, the heat strip turns off. 


I forgot to write down some details but the following should be accurate.


*A) With #5 Relay wire removed:* 

1) Heat mode = fan will come on but the heat strip does not.

2) A/C mode = everything in ac mode functions properly. However, heat strip comes on immediately after a/c mode cycles off. 


* while ac/fan runs, there is 120volts between Sequencer M1 and Relay #1 (green tstat wire). There is -0- volts between Sequencer M1 and #5 Relay terminal.

* when ac/fan stops, there is 120volts between Sequencer M1 and Relay #1 (green tstat wire). There is then 240volts between Sequencer M1 and Relay #5 Relay terminal. 



*B) With #5 Relay Wire attached: (fan runs non stop, as noted issue)* 

1) Heat mode = fan runs constantly, but heat strip doesn't come on.

95amps between Sequencer M1 and Relay #1 (green tstat wire). There is -0- volts between Sequencer M1 and Relay #5.

2) A/C mode = fan runs constantly, but does cool house with normal a/c cycling. Heat strip doesn't come on. 

120amps between M1 and Relay #5. -0- volts between M1 and Relay #5.

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Does this indeed indicate a bad Sequencer or something else? Thanks, Ralph


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## Ralph III (Oct 7, 2011)

*Problem Solved*, well almost!

Thanks to all, especially Houston and Missouri Bound for the help.

It was indeed my upper Sequencer causing our blower to run continous. The thing actually fell apart when I replaced it today, due to corrosion. I guess it locked up when I re-applied power after the breaker replacement. 

Just FYI for those who may be unaware. It's not just your Relay that can cause a blower to run continuous but the Sequencer can cause it also. 


My setup is such that a wire runs from the left side of the Sequencer (normally -0- volts) down to the Relays #5 terminal. This is partly a redundant safety feature as it insures the fan will always run with a call for Heat. 

Anyhow, my top Sequencer became stuck in the closed position which consequently allowed the second leg of 120v to flow continously down to the #5 Relay terminal. The #2 terminal(120v) typically supplies this second leg. When the Relay is energized, the #2 is closed with the #4 (first leg of 120v) thus supplying 240v total to fan. My Relay was functioning properly but as both the #2 and #5 were hot, it caused my fan to run continous no matter the tstat setting.

I discovered my lower Sequencer is defective also (froze in the open position) and thus cannot energize the respective heating elements. I think this must have occurred during our last cold snap because I recall the heater seemingly running non stop at that time. It obviously was because only half of our elements were actually warming the house. I will replace it next week...

Thanks again!

God Bless


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## REP (Jul 24, 2011)

If someone has changed the wiring,it would show up on the wiring diagram that should be on the inside of one of the panels of the air handler.
If you have a meter ,you should check the low voltage wires on that little relay.If you don't have voltage there then the blower should shut off.
If there is no low voltage and its still running ,your line voltage hot could be on the wrong side.
You are just going to have to find the diagram and check out each wire one by one.
Another question,does the new relay have the exact same number of spade terminials as the old one?or does it have an extra terminal?


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## Ralph III (Oct 7, 2011)

REP said:


> If someone has changed the wiring,it would show up on the wiring diagram that should be on the inside of one of the panels of the air handler.
> If you have a meter ,you should check the low voltage wires on that little relay.If you don't have voltage there then the blower should shut off.
> If there is no low voltage and its still running ,your line voltage hot could be on the wrong side.
> You are just going to have to find the diagram and check out each wire one by one.
> Another question,does the new relay have the exact same number of spade terminials as the old one?or does it have an extra terminal?


Thanks Rep. 

As noted, everything is working properly now or as expected. The original Relay was actually functioning correctly. The problem was the heat Sequencer was stuck closed and thus feeding a continous 120v to the Relays #5 terminal, which is normally inactive/off mode. The Relay would correctly switch back and forth between the #5 and hot #2 terminal, but as both were now hot the fan would run continous.

All I need to do now is replace the lower heat Sequencer because it will not close and thus the lower heating elements won't turn on. I tested it for 30 minutes and it never switched. That really isn't an issue at this time because our winter days are over for now, so no need for heat mode.

Take care, Ralph


P.S. Yes, the Relay I purchased was identical to the original. That turned out not be the problem but no harm in replacing it, given the accumulated corrosion to all those old components. I also megged everything in troubleshooting but misunderstood the lower Sequencer.


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## RedneckFarmer (Jun 2, 2016)

Ralph III,

Thanks for your detailed posting.

I had almost the exact same failure on my Rheem air handler this week. I was trouble-shooting a failed control transformer problem. In tracing the wiring, I must have caused the sequencer (hanging upside-down) contact to fall a bit - 1/4 inch [I presume it was broken like yours because it physically came apart].

When it fell, the NO contact CLOSED and put voltage on my evaporator fan motor - thus the air handler fan was running continuously.

I suppose that I could replace the sequencer module, but in the short term, I simply tied the sequencer together using a plastic tie-wrap.


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## Bitters (May 28, 2014)

You do know that post is 4 years old?


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## RedneckFarmer (Jun 2, 2016)

Yes. I do realize that this post is very old; however, by posting this, Ralph III helped me a bit - many years later. I was just trying to show my gratitude. 

Furthermore, by adding to the post, perhaps somebody else might benefit from my experience. Since reading Ralph III's post, I have actually come across at least 2 others with similar experience - including one person (also a few years ago) who has the same Rheem unit that I do.

In my case, I believe that the actual control wiring was helping to keep the sequencer "together;" i.e., not permitting much room for it to physically move.

These sequencers (described as "cheap") in one video I watched, seem quite troublesome.


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