No power to heat pump...

Jabroni

Jabroni

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Woke up to a cold cabin this morning..more than due to the snow! Our heat pump appears to not have power, no power to thermostat, no nothin... Bah!

Checked the breaker for the air handler and heat pump and both were not tripped. I reset them anyways along with the main.. Checked the big fuses for each unit..look fine. Popped cover on the air handler..no melted wires or loose connections, etc.
I can check to make sure its at least getting power from the breaker once I get a fire going.. Any thing easy I can check along with that before I just kick it and curse at it?
 
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Are there secondary breakers or disconnects close to the two units?
 
No, just bug ass fuse looking things..both are giod..

Just had a thought...batteries on thermostat....
 
Jabroni said:
No, just bug ass fuse looking things..both are giod..

Just had a thought...batteries on thermostat....
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Batteries are typically for backup only during outages. The thermo should be powered by the trickle of juice on the line.

Any fuses on the motherboard of the heat pump?
 
My air handlers are under the house. In addition to the disconnect outside at the heat pump, there’s a secondary breaker panel near the air handler.
 
Doh..Wrong house..this thermo has no batts upon checking. Mustw been the old house. Heh. Gonna do more digging after a quick shower.
 
muskrat said:
Check for an automotive style fuse in the air handler.

Here's a video that explains it all. I had this happen to me once.

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We have a winner! Didnt see it upon first look, but did licate it, and sure enough.. popped. Guess what I dont have a spare of ? Yeah.. great. My nearest neighbor is checking to see if he has one though.

Thx for the help fellas!
 
Jabroni said:
We have a winner! Didnt see it upon first look, but did licate it, and sure enough.. popped. Guess what I dont have a spare of ? Yeah.. great. My nearest neighbor is checking to see if he has one though.

Thx for the help fellas!
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You do have a spare...does the horn on the car really need to work today lmao
Find one in the car you can live without for a day or two and use it
 
Can you "borrow" a similarly rated fuse from your vehicle? You're not gonna be driving anywhere soon. ;)
 
Great minds think alike. :D
 
Well..I jury rigged a tube style 4a slow blow fuse..its got power as I can hear the tranformer humming, but it wont run..we had power at the thermostat for a few then not. Heat pump never went into defrost mode or anything, blower never came on, etc. Hrm. Makes me wonder if the capacitor for the blower is out too, or what. Ill steal a 5a from my truck after bit here and see if maybe my quick "fix" is really not working.
Stay tuned!
 
The fuses on our vehicles are min 7.5a so will just wait it out to get a replacement, would rather err on the side of caution. hoping tomorrow we can get out, but who knows. 18in of snow here. At keast the fireplace and mr buddy are keeping us warm.
 
The reason you have a fuse is to protect the circuitry and wires from meltdown. You either have a wire shorted, board short, or a bad transformer. If you have a meter you can check the transformer secondary voltage and grounded condition. Regardless you will not get a transformer today. You have more problems than the fuse.
 
BlackGun said:
The reason you have a fuse is to protect the circuitry and wires from meltdown. You either have a wire shorted, board short, or a bad transformer. If you have a meter you can check the transformer secondary voltage and grounded condition. Regardless you will not get a transformer today. You have more problems than the fuse.
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Possibly, however when it happened to me nothing else was wrong. It's been running great for years since replacing the fuse.
 
Jabroni said:
Well..I jury rigged a tube style 4a slow blow fuse..its got power as I can hear the tranformer humming, but it wont run..we had power at the thermostat for a few then not. Heat pump never went into defrost mode or anything, blower never came on, etc. Hrm. Makes me wonder if the capacitor for the blower is out too, or what. Ill steal a 5a from my truck after bit here and see if maybe my quick "fix" is really not working.
Stay tuned!
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Do not put a bigger fuse than was originally in it. If you go over 3-5 amp fuse you will be greatly disappointed in the cost of repairs. The wires will become the fuse.
 
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One thing to check is if you have power at the circuit board fuse holder. I had a carrier board go bad, poor design, logic chip cooked,
new model used a Microchip programmable microprocessor, this replaced over a dozen components.
 
I read this post earlier, but decided to not comment.
The fuse blew for a reason.
Somewhere in the low voltage circuit there is a short.
Could be the thermostst wires.
Could be defrost board.
Could be numerous things.
You need to call someone who can diagnose what's wrong and fix the problem.
This isn't the 'headlight bulb' from another recent post.
 
325rto said:
I read this post earlier, but decided to not comment.
The fuse blew for a reason.
Somewhere in the low voltage circuit there is a short.
Could be the thermostst wires.
Could be defrost board.
Could be numerous things.
You need to call someone who can diagnose what's wrong and fix the problem.
This isn't the 'headlight bulb' from another recent post.
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It could have been a transient issue.
 
We run into intermittent issues like this sometimes. We go out and find a blown control fuse but can't find anything that would have caused it. We have found a couple where the tstat wire would move just right and short while the unit was running and vibrating. It sometimes takes us putting a small test breaker in place so we don't go thru 100 fuses looking for the problem. Other times we spend hours looking and still can't find anything so we put a fuse in and make a note in our computer system in case it happens again.
 
cmw2212 said:
We run into intermittent issues like this sometimes. We go out and find a blown control fuse but can't find anything that would have caused it. We have found a couple where the tstat wire would move just right and short while the unit was running and vibrating. It sometimes takes us putting a small test breaker in place so we don't go thru 100 fuses looking for the problem. Other times we spend hours looking and still can't find anything so we put a fuse in and make a note in our computer system in case it happens again.
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Nailed it. Fuses can and do frequently fail for no reason. A continuous short will make it fail again immediately an intermittent one not so much. An overload only when the overload occurs again. Fuses are there for a reason. Put one in and see what happens before spending dollars chasing a ghost.
 
Schattenreiter said:
Nailed it. Fuses can and do frequently fail for no reason. A continuous short will make it fail again immediately an intermittent one not so much. An overload only when the overload occurs again. Fuses are there for a reason. Put one in and see what happens before spending dollars chasing a ghost.
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He has already put another fuse in and it popped it. Time for diagnostics.
 
as said above use only the size fuse there usually a 3 or 5 amp take a look at the thermostat wires outside tend to get hit with weedeaters can short out in wet weather
 
Pink_Vapor said:
Friggin' Volvo

The cigarette foil paper wrapped around a blown fuse to get ya home, or burn your shin fix is missing.
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Haha. A 40 year veteran owner of a HVAC company used to tell his employees to cut a piece of copper pipe and use it for a fuse in a fusible disconnect if they couldn’t find a fuse by days end. Love those veteran old timers. Death awaits the unaware and uneducated.
 
BlackGun said:
Haha. A 40 year veteran owner of a HVAC company used to tell his employees to cut a piece of copper pipe and use it for a fuse in a fusible disconnect if they couldn’t find a fuse by days end. Love those veteran old timers. Death awaits the unaware and uneducated.
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went to a 10 ton package unit at a pizza hut about 25 yrs. ago and found 3 5/8 deep well sockets in the disconnect box
 
BlackGun said:
Haha. A 40 year veteran owner of a HVAC company used to tell his employees to cut a piece of copper pipe and use it for a fuse in a fusible disconnect if they couldn’t find a fuse by days end. Love those veteran old timers. Death awaits the unaware and uneducated.
Click to expand...
I've been to several old electric furnaces that had those field expedient fuses you mention.
 
Amazon is your friend. My wife informed me Friday night when I was getting ready for bed our dryer wasn’t working. Pulled it apart after breakfast Saturday and found the thermal fuse was popped. Everything else checked out as best I could tell. No supply houses were open. Checked around on amazon and they had it for $6 with $6 same day shipping. Part shipped from Columbia and arrived by 7pm. I installed it and she has now done around 10 loads of laundry since. I did run over to Lowe’s to see what new dryers they had in stock just in case.

I keep spare contactors and capacitors for my heat pump/AC units around just for this reason.
 
Update...after finally getting internet back (it went out late yesterday)...

So, the 18 inches of snow melted down to 10 inches of slushy mess, so I was abke to make it out to advanced auto this morning for a pack of 5amp fuses. The slow blow I rigged up was a 4amp btw, and never popped, but I question my jury rigging in this case.. any how, after almost getting stuck in the drainage ditch along our driveway, made it back and got the fuse installed. Power showing at the t-stat, so we put it to "heat" and the power went out on the t-stat immediatly. Welll...sheeeit.
Put t-stat to "emergency heat" aka the heat strips..swapped fuses again, and we are up and running!
I would at this point think there is some kinda short on the low voltage somewhere...I couldnt see any shorts in the air handler while I had it opened so I assume it might be outside..perhaps some rodents did something.. who knows. So still need to get a pro out to trace that out.. I could if I had the time, but Im also going out on vacation for two weeks so gotta wrap up a ton if work this week. Pkus I need to have em check the unit anyway..I know we have a slow leak and didnt get them out in the fall to check it. So hopefully we can get this last bit sorted soon..

Really appreciate all the help and ideas here fellas!
 
I had a very similar issue with my heat pump recently. cool and e-heat worked fine but the fuse would blow the instant i turned on the heat. after burning up half a pack of 5 amp fuses I replaced the t-stat and all has been fine since.
 
so it blows in heat mode but not emergency mode ? problem is most likely at outdoor unit. could be a bare wire getting wet in the snow ????
 
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