A/C plastic smell

major bumm · 07-21-2020, 09:18 AM

Hi all,

Camper A/C unit is original and has worked very well for all most 4 years now. Yesterday, a new smell of hot or burning plastic appeared. Checked unit inside, no visible signs of damage. Felt around inside, nothing was warm to the touch. On the roof, the unit did not have anything looking or feeling out of place. no smell either.

Anyone else have a similar experience?

Thanks in advance!

**flybouy** · 07-21-2020, 09:36 AM

I'd suggest a thorough look at all wiring, wire connections, inside and out (remove a/c shroud). That "plastic burning" smell could be wire insulation melting and potentially catching fire. Check inside your power distribution (breaker box) for overheating wires.

Dennisjane · 07-21-2020, 09:53 AM

Quote:

Originally Posted by major bumm

Hi all,

Camper A/C unit is original and has worked very well for all most 4 years now. Yesterday, a new smell of hot or burning plastic appeared. Checked unit inside, no visible signs of damage. Felt around inside, nothing was warm to the touch. On the roof, the unit did not have anything looking or feeling out of place. no smell either.

Anyone else have a similar experience?

Thanks in advance!

I am having the same issue runs fine in early morning when it starts getting hot out I thought I smelled plastic and it trips the breaker. I am calling a mobile repair guy

Canonman · 07-21-2020, 10:01 AM

We had a similar issue after returning to the Cougar after a day of site seeing. Found the problem was the main neutral wire in the power distribution box had come loose. Not off, but loose. Bad connection caused the wire to over-heat and that lovely burning plastic smell. Marshall's suggestion to check the power distribution center might seem odd, but trust me, the problem could be there. Disconnect the shore power and check all the terminals for tightness.

Roscommon48 · 07-21-2020, 10:45 AM

wiring issue somewhere....start seeking out the smell.

major bumm · 07-21-2020, 11:03 AM

Quote:

Originally Posted by Canonman

We had a similar issue after returning to the Cougar after a day of site seeing. Found the problem was the main neutral wire in the power distribution box had come loose. Not off, but loose. Bad connection caused the wire to over-heat and that lovely burning plastic smell. Marshall's suggestion to check the power distribution center might seem odd, but trust me, the problem could be there. Disconnect the shore power and check all the terminals for tightness.

Thanks to everyone!

Checked wiring on roof section, all looks normal. The breaker box, aside from needing a dusting, looks tight.

The smell is slight around the vents of the unit. Yup, I had to stick my nose it.

But, going to take the cover off and inspect further.

The only thing I can think of if inside looks normal is the fan motor. It looked fine, but can not be really inspected properly by me. would call on the professionals for that.

bobbecky · 07-21-2020, 02:10 PM

We had a blower fan crack on one of our A/C units several years ago, and besides making more noise, there was a burning plastic smell, which was the fan rubbing on the housing.

Bill-2020 · 07-21-2020, 06:28 PM

Pull the plastic cover off of the compressor of the roof unit (single hex nut on top, three wires inside). Our's had a burned the common wire off, it literally cooked itself off, melted the wire and melted the inside of the cover. Poor connection caused heat to build up until it failed. Brand new unit in October at that. I have an EMS, always used an EMS. It never tripped anything, just stopped cooling and I went looking, boy did I smell it up there.

bobbecky · 07-22-2020, 08:05 PM

Quote:

Originally Posted by Bill-2020

Pull the plastic cover off of the compressor of the roof unit (single hex nut on top, three wires inside). Our's had a burned the common wire off, it literally cooked itself off, melted the wire and melted the inside of the cover. Poor connection caused heat to build up until it failed. Brand new unit in October at that. I have an EMS, always used an EMS. It never tripped anything, just stopped cooling and I went looking, boy did I smell it up there.

Your EMS can not see anything on the load side, but can only see incoming power from where your shore cable is plugged into. It is protecting your rig from bad power before it gets to the rig. Your breakers in the rig's panel are what helps protect the rig from a fault inside your rig.

MellowSoul · 07-23-2020, 12:19 AM

Not sure if that's the same thing, but we have the same issue with our heater when it's turned on for about 25 minutes. The smell is like mix of dust and something burnt, and that's not a problem at all. What's the model of the AC?

Bill-2020 · 07-23-2020, 02:21 AM

Quote:

Originally Posted by bobbecky

Your EMS can not see anything on the load side, but can only see incoming power from where your shore cable is plugged into. It is protecting your rig from bad power before it gets to the rig. Your breakers in the rig's panel are what helps protect the rig from a fault inside your rig.

Understood. The service center was implying that we had bad power to trailer and that’s what caused it to burn off. I took them my EMS and asked how then “when this is what I use.”

Bill-2020 · 07-23-2020, 02:23 AM

Quote:

Originally Posted by bobbecky

Your EMS can not see anything on the load side, but can only see incoming power from where your shore cable is plugged into. It is protecting your rig from bad power before it gets to the rig. Your breakers in the rig's panel are what helps protect the rig from a fault inside your rig.

Quote:

Originally Posted by MellowSoul

Not sure if that's the same thing, but we have the same issue with our heater when it's turned on for about 25 minutes. The smell is like mix of dust and something burnt, and that's not a problem at all. What's the model of the AC?

Dometic Brisk Air II (13.5)

**flybouy** · 07-23-2020, 04:35 AM

Quote:

Originally Posted by MellowSoul

Not sure if that's the same thing, but we have the same issue with our heater when it's turned on for about 25 minutes. The smell is like mix of dust and something burnt, and that's not a problem at all. What's the model of the AC?

That's not the same thing. Your furnace will collect dust inside and when first fired up will smell like burning dust. If you smell a "burning plastic" then you have an issue that needs investigating.

ChuckS · 07-23-2020, 07:57 AM

id take the cover off the air conditioner and while its running feel around and do some smell checks... id also lay a finger or two on the fan motor when its running..

of course... live 120vac circuits so exercise common sense and watch where you put hands and fingers.. what ever is getting hot is at the roof level because you noticed plastic smell in the ductwork...

also locate the gateway interface box for that air conditioner as well as control module box and verify one of them isnt overheating

travelin texans · 07-23-2020, 08:29 AM

Quote:

Originally Posted by MellowSoul

Not sure if that's the same thing, but we have the same issue with our heater when it's turned on for about 25 minutes. The smell is like mix of dust and something burnt, and that's not a problem at all. What's the model of the AC?

You'll probably have that the 1st couple times using the furnace every season. The only connection between the furnace & ac is the thermostat, different ducts, different power supply.

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