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Heat Pump/Heat Strips Problem?

Nichols747's picture

All,


I have a Goodman MFG ARUF061-00A-1B Airhandler with the optional HKR-20C Heat Strips installed in new construction, 2ksf home. 


When running the T-stat in Emergency mode, to activate the heat strips (trying to heat up the house from outside cold temps), the unit will start operation, produce heat, and run for a few hours.  When I come back to check on things hours later, the unit has shut down, and I find that one of the factory installed 60amp breakers that are incorporated into the heat strip unit has tripped. 


When running the unit in Heat mode (running the heat pump function), it will operate constantly without interruption.  The problem is, that with the cold temps, the unit is taking forever to heat the house.  (4 degrees F in 12 hours overnight)


The electrician is going to check his work tomorrow, but the HVAC installer feels that it is not a problem with the unit - he believes that the unit is not getting enough power, causing the breaker to trip.  I know little about electricity, but this doesn't make sense to me.  Also, there are matching 60amp breakers at the electrical panel, which are not tripping. 


Am I wrong - is a lack of power the possible culprit?  Any other ideas to check out would be greatly appreciated!

Thanks,


AN

(post #113837, reply #1 of 15)

That appears to be a 20 kw heater. And it draws 83.3 amps.

I don't remember the details of electric heat, but I *think* that you are limited to 60 amps per feed. And you I *think* that you need 125% higher than the load for the feeders and breakers.

If those I remember correctly then you will need two 55 or 60 amp circuits. And there should be some staging control on the heaters to allow different banks to be feed by separate circuits.

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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #113837, reply #2 of 15)

All,


I believe that the problem has been solved, the wire at the Breaker was not tightedned fully, now is, will see if it trips again.


Bill, sorry I wan't clear, there are two 60amp breakers going in,  one of them was tripping - my bad.


I guess that I should change this from a technical Heat Pump thread to a "check the simple connections/solutions" thread.  Hopefully, our problem has been solved.


 


Thanks again,
AN

(post #113837, reply #3 of 15)

It would appear that I was too hasty to dismiss this problem.  45 minutes after reactivation, the breaker tripped again. 


The electrician checked his work today, and here is some more information:


He switched the feeds going into the two 60 amp breakers, ran the system, and the same breaker tripped.


He says that the only evident difference between the two breakers is that the non-tripping one feeds half of the heat strips, and the tripping one feeds half of the heat strips as well as a circuit board which appears to control the system (powers the airhandler). 


While he wasn't watching it when it tripped, that side of the setup was drawing 43amps and 245volts for about 35 minutes.


Any thoughts?

I think that this will require a service tech visit - would anyone disagree with me thinking that this must be a problem with the HVAC side, rather than the electrical?

Thanks,



AN

(post #113837, reply #4 of 15)

"While he wasn't watching it when it tripped, that side of the setup was drawing 43amps and 245volts for about 35 minutes."

Unless there was a large spike them the problem is in the breakers/panel.

"He switched the feeds going into the two 60 amp breakers, ran the system, and the same breaker tripped."

Switching the LOADS would be much more informative.

Unless there is some surge in the load (which switching loads would show) the problem is either a weak breaker or bad connections which causes extra heating on the breakers.

The electrican should have checked for that when it tripped.

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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #113837, reply #5 of 15)

Right about switching the loads, I think that he didn't want to do that, since the breakers are part of a preassembled "plug-in" heat strip set, and he was hesitant to mess with it.  I think that he was concerned about warranty/returnabillity.


He was going to switch one of the other Siemens 60amp breakers in to see if that one tripped, but the Siemens breakers in the heat strips are dissimilar to the ones in the panel.  Then he was going to switch the breaker positions (tripping to non-tripping) to see if the failure switched, but the screws seem to be covered with some sort of seal/glue.  Another concern about voiding the warranty.


I think that I need to get an HVAC service tech out - evidently my installer is not a service tech. 


Thanks for your input Bill,

AN

(post #113837, reply #6 of 15)

It's unusual (especially for a Siemens) but not impossible for the breaker to be defective tripping at a lower current than rated.

Convince the HVAC guy to replace the breaker.

Good luck

(post #113837, reply #7 of 15)

It sounds like something's miswired, or the heat strip or breaker is defective. The total load on the breaker should be well under it's rating, so the breaker would only trip if the heat strip shorts out.

So possibilities:

1) There's more load on the breaker than just the heat strip -- compressor load is on it and that's causing an overcurrent, eg.

2) The heat strip is shorting out internally. Not that unlikely, as resistance heat elements move quite a bit as they get hot, and the element could buckle or some such and short out.

3) The breaker is getting warm and tripping, due either to a bad connection in or at the breaker, or due to heat from the heater elments getting to the breaker, possibly because a cover is missing or misinstalled.

A pure resistance element will not draw more current due to low voltage -- it will draw less as voltage is reduced. So low voltage would only be a problem if the compressor or some other motor load is also on the breaker.


So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #113837, reply #8 of 15)

Thanks for the pointing me in the right direction(s).


The breaker that is tripping is the one which powers the air handler "Squirrel Cage"/fan, which will run for days as long as the heat strips are not on.


It is mounted (from the manufacturer) on the heat strip kit, though not on the metal plate oposite the strips, it does get warm, and will not reset for about fifteen minutes.  After that, it resets just fine. 


Thanks again, any more ideas are appreciated.


 


Andrew

(post #113837, reply #9 of 15)

any time i've had a problem with a goodman unit... their 1-800 tech  people walked me thru every test & function and always came up with an answer on the phone... arranged for replacement parts local for me to pick up... or sent em out next day...


i can't say a bad thing about em...


p

(post #113837, reply #13 of 15)

DanH,


The outside unit (Compressor?) is on a seperate 50 amp breaker, seems to run fine when the system wants it to.


In regards to the breaker heating up from the heat coils, when it trips, it is warm to touch, but not at all uncomfortable to touch.  Could this be enough to cause the failure? Any ideas on how to isolate the breakers? (they come preattached to the heat strip unit)


Sure apppreciate the information,


Andrew

(post #113837, reply #14 of 15)

The question is the breaker generating the heat because of problems in the breaker/connection, is it normal heat, is it heat from the heating elements.

What is the tempature of this breaker verse the other one when both are drawing current.

I am assuming that the heating elements are staged by the thermostat? or by time? you want to have both running and then see how hot the two get.

THERE IS NOTHING IN THE ELECTRICAL SUPPLY THAT COULD BE CAUSING THESE SYSMPTOMS.

Also that the breaker can't be reset for 15 minutes certainly indicates that the "breaker" is getting way too hot.

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.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #113837, reply #15 of 15)

Bill,


Good point, the non-tripping (good) breaker is next to, but closer to the heat strips.  They are the same temp to touch, which is the same temp as the rest of the components/metal in that area. 


Thanks for the good info, I guess I need to the the General Contractor to get this resolved with the HVAC guy/a service rep or tech.


Sounds like I may not be the only person with this problem, hopefully I can get some resolution. 

Andrew

(post #113837, reply #10 of 15)

This is my first post as I am a interested LURKER but the subject is of concern to me as well. I have the same unit and my heat strips have cause the internal air handler breakers to fry on THREE occasions. I am currently on heat strip module #4 ($200 +/- a pop) every time I use emergency heat. I have even changed the thermostat to a simple mechanical unit to avoid any auto switch to emer. heat and use it only as normal heat pump. Installer blames everything but probable cause of faulty unit design.


I have asked if Goodman has issued a field fix or bulletin regarding problem but no response. I wanted you to be aware that this is more than problem with your install or individual module but design flaw of some sort. 


I hope some of you more talented and aggressive tradesmen will pursue this to some sort of conclusion. You guys are great to learn from and hope this will be one that strikes home for me as well.


Lurking Bob 


 

(post #113837, reply #11 of 15)

Go to HVAC-Talk.com; Goodman is not highly regarded if I remember. Cheap, though.

(post #113837, reply #12 of 15)

Bob, thanks for the info, I guess you haven't had any luck coming up with a solution eh?  I am working with an installer who is not a service tech, not sure if this is common, but he keeps pushing the discussion towards an electrician problem.  This doesn't seem to be the case. 


Since you know what the strip kit looks like, can you confirm that you have the same failure:  Unit runs in emergency mode, running heatstrips, blowing hot air, for 30min-a couple of hours, then the breaker which runs half of the strips and powers the small circuit board and airhandler.  The entire unit is warm to the touch, and the breaker will not reset for about fifteen minutes, then is able to reset, and runs again the same. 


Have you found a solution that works?  Is Goodman willing to warranty these problem kits? 


Will go to HVACTalk to see if there is a solution or some more guidance. 


Thanks All,
Andrew