The 35 cent fix!

[Foiled Again]

My air conditioner/heat pump went kapooie last week.

And I just spent a boatload of money - and paid off the new tow vehicle 4 years ahead of schedule... and it's getting cold as hell... and it blew up the thermostat too so the wretched furnace won't work.

So I got out the trusty space heaters, plugged them in and started seriously pouting. I bought the Eddie Bauer used, and when I went to pick it up at Colonial, I stepped inside and there was compressor oil all over the floor. The next morning the service department took another air conditioner off of a new Airstream and installed it in mine so I could get back home on schedule. The original was a 13,500 BTU unit, and that is what they replaced it with. Wasn't too crazy about that and figured I'd eventually have to replace it with a 15,000 BTU unit, but surprisingly the smaller one worked well even in 95 degree weather. I did have problems with the thermostat wiring getting wet - they used a phone jack connection - duh., but I got that resolved finally. So I'm stewing knowing what the replacement cost would likely be - and how inconvenient it will be having to have it done in freezing December.

I just let it go - and muddled along with the space heaters for a couple of days... then a random thought hit me. I checked the circuit breaker again... and wait for it... Thought, AND THE THERMOSTAT WENT BLANK....

is the thermostat on the same circuit breaker as the a/c heat pump? or
(kneeling in prayer in front of the fuse panel reading the schematic)
12 volt
thermostat - slot 10, 15 amp blade fuse

could it be?
visual check - looks OK, but?

Of course I don't have any spare fuses, but what the heck. Pulled the 15 amp fuse for the fantastic fan and swapped it with the thermostat's fuse. And TA-DA, turned on the heat pump and did the happy dance.

Went to the auto parts store and bought spare 15 amp and 30 amp blade fuses, about 35 cents per fuse.

True joy - not spending $100 for a service call and feeling like an idiot when the tech found the problem. Moral of the story, don't be afraid to spend money to keep things in good repair, but never underestimate your own ability to logically eliminate the simple stuff before you panic, embarass yourself and waste money.

With WARM regards, Toasty Paula

[ROBERTSUNRUS]

Hi, in my many years working on cars, I trained myself and fellow mechanics to not over think problems with these cars. Always start with the simplest things first no matter how much you think that it is not the problem.


Note: also don't overlook the thermostat either, some have batteries in them, mine does.

[Bruce B]

Don't you just love it when the answer to a problem just dawns on you out of the blue? It is like a gift from the sub conscious mind...
Nice find!
Bruce

[scamp]

Originally Posted by Foiled Again

My air conditioner/heat pump went kapooie last week.

And I just spent a boatload of money - and paid off the new tow vehicle 4 years ahead of schedule... and it's getting cold as hell... and it blew up the thermostat too so the wretched furnace won't work.

So I got out the trusty space heaters, plugged them in and started seriously pouting. I bought the Eddie Bauer used, and when I went to pick it up at Colonial, I stepped inside and there was compressor oil all over the floor. The next morning the service department took another air conditioner off of a new Airstream and installed it in mine so I could get back home on schedule. The original was a 13,500 BTU unit, and that is what they replaced it with. Wasn't too crazy about that and figured I'd eventually have to replace it with a 15,000 BTU unit, but surprisingly the smaller one worked well even in 95 degree weather. I did have problems with the thermostat wiring getting wet - they used a phone jack connection - duh., but I got that resolved finally. So I'm stewing knowing what the replacement cost would likely be - and how inconvenient it will be having to have it done in freezing December.

I just let it go - and muddled along with the space heaters for a couple of days... then a random thought hit me. I checked the circuit breaker again... and wait for it... Thought, AND THE THERMOSTAT WENT BLANK....

is the thermostat on the same circuit breaker as the a/c heat pump? or
(kneeling in prayer in front of the fuse panel reading the schematic)
12 volt
thermostat - slot 10, 15 amp blade fuse

could it be?
visual check - looks OK, but?

Of course I don't have any spare fuses, but what the heck. Pulled the 15 amp fuse for the fantastic fan and swapped it with the thermostat's fuse. And TA-DA, turned on the heat pump and did the happy dance.

Went to the auto parts store and bought spare 15 amp and 30 amp blade fuses, about 35 cents per fuse.

True joy - not spending $100 for a service call and feeling like an idiot when the tech found the problem. Moral of the story, don't be afraid to spend money to keep things in good repair, but never underestimate your own ability to logically eliminate the simple stuff before you panic, embarass yourself and waste money.

With WARM regards, Toasty Paula

Paula. That's great you got your heat pump working ,as a retired auto tech when a fuse blows there is a reason, either the circuit got overloaded or there was a short circuit to ground . For the circuit to get overloaded this usually happens when someone adds to the original (circuit) design of the trailer ( aftermarket alarms,light, power outlet , etc.) the other that causes the fuse to blow is short circuit this happens when a wire rubs through wire insulation to the ground such as trailer sheet metal, frame etc, or if water gets into a connector and there is a positive and negative wire in the same connector,as water is conductive it cause a short circuit and blows the fuse . In my 34 years of automotive experience I have never seen a defective fuse. Your problem can be intermittent as when the trailer bounces on the road and the wire shorts to ground, it can also happen as temp changes and cause expansion or contraction of a wire or when it's rains . The last thing that could cause the fuse to blow is a defective component ( thermostat etc...). Sorry to be negative but I was just trying to help hopefully the heat pump will work all winter and if the problem happens again hopefully in the warmer weather someone could have a look at it.

Don

[masseyfarm]

Maybe that automotive course paid off afterall?????????????
Dave

[RickDavis]

I have seen many fuses die from old age, vibration, fatigue etc. Often they will develop invisible cracks in the fuse element.

I don't trouble shoot unless the fuse looks like a violent failure, or the second one goes.

[NavyCorpsman]

Sometimes you just have to sit in front of it, fangs out, and stare......I'm glad the fuse blinked.

[Foiled Again]

Thought about your comment that fuses don't generally blow for no reason and pulled my "bad" fuse out of the trash, then reinstalled it.

It worked.

The thing must have just been loose, though it sure wasn't easy to get out. Also I might have had a little corrosion on the terminals that pulling it and replacing it cleaned off.

So I still don't think I wasted $.35 because I have plenty of spares. I did take the time to stow them in the space above the converter so I can find them if I ever need them.

Paula

[Gearheart]

Paula, When a fuse blows there is no mistaking what went down. Big gap of missing metal along with signs of smoke are the norm. A "can't see anything wrong with it"like you described in you first post is not a blown fuse. Vibration metal fatigue most likely cause a crack that broke the circuit and killed the fuse. The symptoms you described at the start, trading out with another fuse just to see because there did not appear to be any fault with the suspect fuse, are not indicative of a blown overloaded fuse.

[rmkrum]

There are replacement blade fuses made that have an LED built in to indicate a blown fuse. This assumes some sort of turned on load to light the LED if the fuse blows. Cost more, but worth it.


Sent from my pocket Internet using Airstream Forums

[carl2591]

learned that the hard way as well.. they can "look" good and be bad. best way to check is use multimeter on continuity setting. most of the time that works well.. (best way is to use a megohmmeter but they are pricy) and ALWAYS have spare fuses for every thing in the coach and truck, which is the some for you..

big pat on back and a glass of wine to celebrate the victory.

Originally Posted by Foiled Again

My air conditioner/heat pump went kapooie last week.


is the thermostat on the same circuit breaker as the a/c heat pump? or
(kneeling in prayer in front of the fuse panel reading the schematic)
12 volt
thermostat - slot 10, 15 amp blade fuse

could it be?
visual check - looks OK, but?

Of course I don't have any spare fuses, but what the heck. Pulled the 15 amp fuse for the fantastic fan and swapped it with the thermostat's fuse. And TA-DA, turned on the heat pump and did the happy dance.

Went to the auto parts store and bought spare 15 amp and 30 amp blade fuses, about 35 cents per fuse.


With WARM regards, Toasty Paula