Damaged a/c condenser fins

[Deb Mac]

Originally Posted by Lloyd (aka Santa) Coltman

Something to consider: almost any outlet close to the trailer's 'Power Centre' will give you almost identical readings to what the A/C will see, as most of your loss will be in the 15A house wiring (14 Ga unless new standard and over 50'. In which case it would be 12Ga). At home, in Kelowna, I can easily run a 13,500 BTU A/C, Converter, and Fridge on a proper 20A (12 Ga. approx 50' )+ 25' 10Ga umbilical.

Hi Lloyd. I put in a new dedicated circuit in the trailer panel for this ac - it is on a 20A breaker using 12/2 Romex. I had the house wiring upgraded a few years back - brand new panel with lots of new circuits in the house! The new circuits installed are 12G MC cable, and all are 15A breakers, including this one.

I was also able to run the 11,500 BTU 40 year old Dometic ac in my '77 GMC motorhome on exactly this outlet from the house. Never had a problem with it. But it also never got this hot!!! And of course, since I never had a problem, I never checked for a voltage drop when it was running.

But I do have a couple of spare spots in my main panel in the house, and I am really thinking I should add a dedicated 20A circuit for the trailer. It wouldn't be terribly difficult. It would be about a 30' run. Run a new MC cable up to the panel from the crawl space and out to a weatherproof box on the side of the house. I installed a transfer switch 3 years ago to deal with the regular power outages up here in the winter and that was a lot more involved than adding another circuit. Inspector was happy. Could be a project for later in the season, or early next year before the heat hits.

[Lloyd (aka Santa) Coltman]

If you have a regular voltmeter, take a reading at a receptacle in trailer (A/C off, then check with Compressor starting, and then with it running (Just for my curiosity).
Yup, it was damn hot this weekend. We went up to Williams Lake last Wednesday to repair sister-in-law's water damaged floor, and fix some plumbing problems in her non-air conditioned mobile home. A little tough on an 82 year old body.
Now I have to figure out why the fan in our 'Town' vehicle (that we use for volunteer work) is cutting in and out (no cooling when it doesn't run).
It also sounds like you're considering a similar set-up to what I have: A dedicated 20Amp breaker in house panel, feeding 12 Ga Romex to RV30 outlet in weather proof box at convenient location to trailer (perfectly legal, as the breaker is sized for the wire, and will disconnect if overloaded).
However, In BC, if the outlet is less than 6' above grade, it must be 'Ground Fault' Protected. I achieved this by running the circuit through a 20A Ground Fault Outlet in my garage (used for no other purpose).

[Deb Mac]

Originally Posted by Lloyd (aka Santa) Coltman

If you have a regular voltmeter, take a reading at a receptacle in trailer (A/C off, then check with Compressor starting, and then with it running (Just for my curiosity).

Hi Lloyd. 118v at the nearest receptacle. 116 with the fan only. Then drops to 108 when compressor kicks in. Maintains at 108V & doesn’t drop below that when it kicks in. Just straight to a steady 108. No lag on the compressor. Doesn’t sound like it’s struggling at all.

[Lloyd (aka Santa) Coltman]

I Just went out and ran same tests on my trailer (w/ Coleman 13,500BTU)

No A/C - 130Vac
Starting Compressor - 120Vac
Running -Low Cool 120-125Vac
High Cool 118-120Vac


Mind you, It's not 35c today, only 28c.

[gordon2]

Originally Posted by Deb Mac

Hi Lloyd. 118v at the nearest receptacle. 116 with the fan only. Then drops to 108 when compressor kicks in. Maintains at 108V & doesn’t drop below that when it kicks in. Just straight to a steady 108. No lag on the compressor. Doesn’t sound like it’s struggling at all.

The more I read of this thread the more I think that you have a power supply problem. But where it is... thats the tough question. Your power seems to be marginal at best... maybe within specs but at the very end of the low range. Perhaps the house supply is being taxed with more load than original planned for. Perhaps there is a bad connection. Perhaps there is inadequate wiring at any point between the power company's transformer and your A/C. Perhaps.. well, I'm not qualified to say but a little internet searching suggests ever more possible causes.

I think I would check with the power company first since they will likely check your home service for free. And they might be able to tell you if voltages fell with the heat wave. After that, you might need to pay an electrician to evaluate the situation.

Or take the camper to a good campsite with proper power on day that is just as hot.. and see what happens. But even then you can't be sure the campground is not experiencing the same brownout or other issue.

Electrical problems (if that is in fact the issue here) can be very difficult to pin down.

[Deb Mac]

Originally Posted by Lloyd (aka Santa) Coltman

I Just went out and ran same tests on my trailer (w/ Coleman 13,500BTU)

No A/C - 130Vac
Starting Compressor - 120Vac
Running -Low Cool 120-125Vac
High Cool 118-120Vac


Mind you, It's not 35c today, only 28c.

It's supposed to be about 28-29C today & tomorrow. I'll give it check mid-afternoon and see if I'm getting the same drop-off as with the 35+ temps. Just for interests sake.

[Deb Mac]

Hi Gordon. It may well be. Though when I had the place upgraded a few years back, the electrician did check everything coming in to the distribution panel and it was up to snuff (or as snuff as it can be in our wee town - WE may not be on the high end of normal!).

About the only thing I think I can do is check a few of the outlets in the house (particularly the one the extension cord is plugged into) and compare them to what I'm getting at the trailer (end of the extension cord) and inside the trailer and look for any drop-off when the ac is running. It's possible that the panel in the trailer isn't working properly as well. If I have a drop-off between the cord and the inside receptacle, I suppose I'll have to take a look at replacing the control panel.

But today's project is finishing up the re-configuring of the waste valves

[gordon2]

Originally Posted by Deb Mac

... It's possible that the panel in the trailer isn't working properly as well. ...

Indeed.. loose connections from all the road travel is common. After the high load has been on for a while.. kill the power and feel every part of the panel you can reach for heat (from a bad connection with high resistance).

[Lloyd (aka Santa) Coltman]

This https://www.canadiantire.ca/en/pdp/m...-0574554p.html is something I carry in my tow vehicle at all times to routinely check tire and hub temperatures, while travelling, and would also help in finding poor connections, while under load. Mine is Harbor Freight Tools, but the 'Canadian Tire' unit is similar, and on sale for 50% price, until July 15.

[Deb Mac]

Checked the voltage at that nearest outlet in the trailer this morning when it was nice and cool out - 23C in the trailer. I know - who needs ac!

But, anyway... 120.2V with no load, 119.8 with fan on low, 118.9 fan on high, 117.8 on low cool with compressor on (and no discernible transient dip as the compressor kicked in), 116.5 on high cool. The unit was pushing out cold air, so the compressor was engaged.

So it seems things are working fine when it's cooler out. I will check this afternoon if it gets warm enough to make it actually work a bit. Or wait till tomorrow - supposed to be a bit warmer (about 30)

And I have no contact thermometer that I will use to check the connections in the panel next time I have it running at anything resembling a load.

I also took a closer look at my extension cord - it is only 14G! (really hard to read - the specs are stamped into the covering rather than written on. Picking up a proper 12G (10G if they have one) cord this afternoon on my Canadian Tire run.

[Lloyd (aka Santa) Coltman]

How long is that 14Ga cord?

A bit of info: If the Voltmeter you're using has similar probes to mine (1/16" dia.), you should be able to retract the plug enough to take a reading of input to the cord (with A/C running) without affecting power. Just be careful not to short, ground, or become part of the circuit.
I would be interested to know what voltages you see at the house plug (no load), then at each connection point out to the 'Umbilical' (RV 30) plug on trailer cord (with A/C running).

In my wife's dog grooming salon, I was constantly replacing 15 Amp plugs and receptacles for the 1500 watt (12.5 Amp) driers, because the continual heavy draw would weaken the contact springs (especially on standard grade receptacles), causing poor contact and more heating.
I've spent a good portion of the afternoon chasing down an electrical problem on the heat&/A/C fan in our vehicle. It was cutting out and then 'Not Cool'
BTW it's 34c here now (two different thermometers on North exposure).

[Deb Mac]

Got a nice new 12/2 extension cord. 50’.
Plugged everything in and checked the voltage at the perpetual “nearest outlet”. 120.2V. Couldn’t check the end of the cord itself because the contacts are quite deep in the socket and my probes would reach. Also 120V at the house outlet that it is plugged into.

There is an adapter (15/30A) between the cord and trailer power plug and I noticed it seemed rather warm on the trailer side. Checked the prongs on the 30A plug and they looked like there was some paint on one of them. I got some fine sandpaper and cleaned the prongs. Plugged it in again and let it run for about 15 minutes. Much cooler!! I am also going to upgrade that adapter

Tried the ac again. 120V no load, 119.9 low fan, 119.7 high fan, 116.8 low cool, 115.7 high cool. It was 33C in the trailer at the time.

Checked the breaker panel with my no contact thermometer while the ac was running and all breakers were sitting happily at 32C except the main 30A which was at 34.2C

I’ll check it all again tomorrow. Going to be warmer and I’ll have more time to check it on a longer run time.

[Lloyd (aka Santa) Coltman]

Sounds better all the way through.
When checking temp of 'breakers' did you check at 'output' terminals'? (that's where loss/heat will occur)

You should also check all 'Neutral' (white wire) terminals, what goes out has to return, and if not tight there will be resistance/loss.


I have a 12-2 x 50' with a weatherproof box/RV-30 outlet, that I call a 50' adapter. It came with a 'Twist-lock' socket (meant for a transfer panel). It was part of a package, including a similar cord with standard end, and a used 2200 watt Yamaha generator.

[gordon2]

Mystery solved... insufficient extension cord.

Now if you do try to straighten the fins, be careful... I have heard its easy to damage them in the process and I have heard (but can't confirm) that its better to just leave them alone.

[Lloyd (aka Santa) Coltman]

I was re-reading this entire story, when I noticed your statement that the 'Main' breaker was reading ~ 2.2c higher than the others. Why? Did you check tightness of the terminal screw on it, as well as the corresponding 'Neutral' (white wire from 'Umbilical') terminal?
Those two connections are part of the original installation, and may have loosened a bit, over time.
Remove the power centre cover, and scan all connections with your 'No Contact' thermometer, with A/C running. That should reveal any poor connections.
Are you getting much smoke from the Durand Lake fire?