Furnace troubleshooting

[Rockhead]

Call progressive and see what they say you could have an ems that’s got a bug in it if so they’ll send you a new one free

[WillyB]

Originally Posted by John in Santa Cruz

before you get the E4, with just that heater element (and the ac fan) running, what does the EMS show the current is ? I would expect around 12-13 amps if its a 1500 watt heater.

John,

Thanks for the suggestion.

This morning I checked the EMS Readings.

Before Turning on the Mach 10 Heater
** 123 Volts / 0 Amps (Nothing on in trailer)

After Turning on the Mach 10 Heater
** 107 Volts / 10 Amps (Heater only thing on)

I would assume that the extension cord I'm using is either too long or not a large enough gauge. It is 75 feet and 12/3.

Thoughts?

[Rockhead]

At that length should use 10 gauge for less voltage drop

[WillyB]

I’m just wondering even at 10 ga whether I’ll have a high enough voltage on the low side above the 104 v cutoff on the EMS.

All the more reason to put a 30 amp receptacle at the carport back to the panel box in the house.

[John in Santa Cruz]

I wonder if its a wiring issue at the outdoor outlet you're using?

150 feet (round trip) of 12 AWG *copper* is only 0.238 ohms. 0.238 ohms at 10 amps is 2.38 volts, therefore you should only see a 2.38 volt drop from your 123 V at idle. 200 feet of 12/3 (100 ft each way) is 0.318 ohms, which is a 3.18 volt drop, again well within safe margins.

now, if that 12/3 cord is chineseum, they are notorious for under gauge wires with copper clad aluminum (CCA), *GARBAGE*.

[John in Santa Cruz]

btw, 200 feet (100 ft cord round trip) of AWG 10 copper wire is 0.2 ohms, so at 10 amps, thats a 2V drop, or at 30 amps, a 6V drop.

[Iowa Dave]

We ran #10 wire about 35 feet from the panel to a convenient location for our RV receptacle. My brother put the fluke meter on it and there was very little drop from the panel to the receptacle. I have a regular extension cord made from a removable cord. It’s about 25 feet long. We’ve also run the Escape on a 20 amp circuit with a #12 extension cord, 50’ long. That’s all we have ever needed. Heavier is better when it comes to extension cords in my experience. We use all heavy duty breakers in our panels
Iowa Dave

[John in Santa Cruz]

Originally Posted by John in Santa Cruz

I wonder if its a wiring issue at the outdoor outlet you're using? ...

I think I would hook up a digital multimeter in AC Volts mode to a cube tap, and plug that cube tap into the outlet, and a 1500 watt electric heater directly into the cube tap and measure the voltage with the heater off and on to verify that there's only a minimal voltage drop at the outlet, just to eliminate that variable.

[Iowa Dave]

Good thought. I had 25 rental pavilions at one time. They all had serving counters with duplex outlets. They took a beating from the public and from vandals. My maintenance guys all had meters and we were often changing both receptacles and breakers. We did have an excellent relationship with the electric utility who would come out anytime we suspected low voltage (brownouts) especially on hot summer days. Those were hard on pool pumps too.
Iowa Dave

[Grasshog]

Originally Posted by Perry Butler

Same here, but we have two spare sail switches, so ours should last twice as long.

Enjoy,

Perry

In the past I have had different trailers, the newest a 2019 Rockwood, the other 2004 Komfort never had any issue with any furnace and it’s kind of bewildering to me that this problem is so common that I have to bring spare parts with me I guess it’s the old adage they don’t make them like they used too?. getting ready to take delivery and I’m actually really excited !!! but for the price I paid I’m not sure I’ll be able to afford spare parts ha ha 😎😂

[WillyB]

Originally Posted by John in Santa Cruz

I think I would hook up a digital multimeter in AC Volts mode to a cube tap, and plug that cube tap into the outlet, and a 1500 watt electric heater directly into the cube tap and measure the voltage with the heater off and on to verify that there's only a minimal voltage drop at the outlet, just to eliminate that variable.

I moved the extension cord from the receptacle on the patio to the one in the garage. Both on different breakers. Same result in voltage drop.

I then did some calculations on what is required to have a 120/1 15 amp power at the camper. I am way past the maximum on a 12 Ga and 10 Ga wire from the panel box with a 75 foot 12 ga extension cord (even 10 Ga) plus the removable cord on the camper.

From my calculations I will run 10 Ga wire from the panel box to a 15 amp duplex at the camper. This should give me full 15 Amp power at that receptacle. It looks like 114 feet is the max on 10 Ga for this and I'll be right at a 105 feet line run from the panel box.

Oh well, I was planning on adding a 120/1 15 Amp receptacle on it's own breaker anyway. I just thought I could run the heater off an extension cord for now.

FYI, our panel box is on the complete other end of our house. As a crow flys, about 90 feet from the camper.

[Ooshkaboo]

Originally Posted by WillyB

I moved the extension cord from the receptacle on the patio to the one in the garage. Both on different breakers. Same result in voltage drop.

I then did some calculations on what is required to have a 120/1 15 amp power at the camper. I am way past the maximum on a 12 Ga and 10 Ga wire from the panel box with a 75 foot 12 ga extension cord (even 10 Ga) plus the removable cord on the camper.

From my calculations I will run 10 Ga wire from the panel box to a 15 amp duplex at the camper. This should give me full 15 Amp power at that receptacle. It looks like 114 feet is the max on 10 Ga for this and I'll be right at a 105 feet line run from the panel box.

Oh well, I was planning on adding a 120/1 15 Amp receptacle on it's own breaker anyway. I just thought I could run the heater off an extension cord for now.

FYI, our panel box is on the complete other end of our house. As a crow flys, about 90 feet from the camper.

Just a thought on your troubleshooting, if you were to move your camper close to your house for a bit then run the heater. See how it performs with just the supplied camper cable.
It would then let you know if the problem is the feed line you are now using.

[WillyB]

Originally Posted by Ooshkaboo

Just a thought on your troubleshooting, if you were to move your camper close to your house for a bit then run the heater. See how it performs with just the supplied camper cable.
It would then let you know if the problem is the feed line you are now using.

Unfortunately that's not possible. I'm confident the house electric is operating properly. If my calculations are correct a 12/3 wire can only handle 15 amps up to a max distance of something like 85 feet and I'm way past that running a 75 extension cord plus the Escape cord.

I had planned on running a separate line any way because I didn't want to hassle all the time with extension cords.

[Ooshkaboo]

Originally Posted by WillyB

Unfortunately that's not possible. I'm confident the house electric is operating properly. If my calculations are correct a 12/3 wire can only handle 15 amps up to a max distance of something like 85 feet and I'm way past that running a 75 extension cord plus the Escape cord.

I had planned on running a separate line any way because I didn't want to hassle all the time with extension cords.

Yes eventually a permanent setup will be great, maybe even more than a 15 amp.

I was understanding you had concerns about the temporary setup with your extension cord possibly being a factor with your poor heat strip performance.

The RV parks seem to usually have a 20, or run it over to a friends with a 15 amp.
Using only the Escape provided power cord you would then get an answer as to if the extra extension cord you’re using is a factor.

We will have some colder weather in a few days, if it helps I’ll start mine up and test it out. I’m right at 55’ off an outlet connected to my deck.

[John in Santa Cruz]

Originally Posted by WillyB

From my calculations I will run 10 Ga wire from the panel box to a 15 amp duplex at the camper. This should give me full 15 Amp power at that receptacle. It looks like 114 feet is the max on 10 Ga for this and I'll be right at a 105 feet line run from the panel box.

my calculations given above were a 3V drop on 200 feet of AWG 12 copper at 10 amps, so that would be a 4.5V drop at 15 amps. 123 volts starting - 4.5 volts == 118.5 volts. WELL within safe voltage unless your household source voltage drops below 115V

[Ooshkaboo]

Originally Posted by WillyB

Unfortunately that's not possible. I'm confident the house electric is operating properly. If my calculations are correct a 12/3 wire can only handle 15 amps up to a max distance of something like 85 feet and I'm way past that running a 75 extension cord plus the Escape cord.

I had planned on running a separate line any way because I didn't want to hassle all the time with extension cords.

So here’s what my Coleman heat strip did today.

06:36-32 degrees
08:36-70 degrees

[WillyB]

Originally Posted by Ooshkaboo

So here’s what my Coleman heat strip did today.

06:36-32 degrees
08:36-70 degrees

I have one of those dangerous cheap portable electric heaters that my wife used at her desk years ago and just took it out to the Escape for a test.

Nothing hooked up: EMS 121 Volts

Turned heater on high: EMS 104 Volts

The Bluetooth control on the Mach 10 is super handy! Our Victron controller also has Bluetooth.

[tom&pam]

Thanks, David, for your series on troubleshooting the furnace. Mine quit working last week and I took it to a shop for warranty repair. The tech tried a Dinosaur board and recommended that product. That did not solve the problem and he then removed the sail switch and worked the contact while it was still plugged in. He then replaced the switch, and my furnace works.

When I talked with Dometic, they would not give me any troubleshooting hints, but they did send me the service manual. That manual might help some other owners. I was going to upload the manual, but it is too big for the forum. Is there a workaround for uploading bigger files?

[YakRV]

Originally Posted by tom&pam

Thanks, David, for your series on troubleshooting the furnace. Mine quit working last week and I took it to a shop for warranty repair. The tech tried a Dinosaur board and recommended that product. That did not solve the problem and he then removed the sail switch and worked the contact while it was still plugged in. He then replaced the switch, and my furnace works.

FYI, it has been recommended by several owners on this forum to keep a spare sail switch on hand in the event the new one fails. I second (or is it third, fourth, or fifth, etc?) that advice. I’ve had to replace two sail switches in our first camping season.

[brroberts]

The service manual would be great to have if we could get it.