Popular New Guides Product Guides Tools Checklists My Rig

Results for "furnace circuit"

783+ Q&A Updated Weekly Free
How to Add Coleman Mach Heat Strips to RV AC Unit - Heat-Ready Control Box Installation Guide
Ac Refrigeration Hard 2-4 hours 103 👍

How to Add Coleman Mach Heat Strips to RV AC Unit - Heat-Ready Control Box Installation Guide

Tried running my RV's electric heating this winter but it's eating through power way faster than it should, so I'm looking at adding Coleman Mach heat strips. I have a SportTrek Touring 272VRK with two AC units (Coleman-Mach 13.5k BTU and 15k BTU, models 48203-069 and 48204-069) with Cool-Only Control Boxes (model 8330-752) and I'm considering adding Coleman Mach electric heat strips, but I'm worried about a few things.

First, I'm concerned about whether my current AC units are compatible with heat strips - specifically the Coleman Mach 37203-4551 Electric Heat Kit/Strip. I want to confirm this will work with my existing 8330-752 control boxes. Second, I'm worried about the electrical load - I keep reading about heat strips drawing a lot of power and I'm scared of overloading my system or tripping breakers.

Most importantly, I absolutely do NOT want to lose the ability to use my existing Suburban SF-30FQ 30,000 BTU propane furnace - it's my primary heat source and I need that independence. I currently have 9420a381 digital thermostats controlling these systems, and I want to ensure I can maintain my current setup.

Is there a way to safely add Coleman Mach heat strips using some kind of Heat-Ready Control Box without compromising my furnace operation? I just want some reassurance that this can be done properly without creating problems. …more
Complete RV Solar System Guide 2024: Sizing, Installation & Wiring
Solar Batteries Medium 4-8 hours 98 👍

Complete RV Solar System Guide 2024: Sizing, Installation & Wiring

Turned to YouTube for RV solar advice and now I'm more confused than ever - probably a dumb question, but how do I actually size this thing? Could fellow RV owners share details about their current solar setups?

Please provide insights on:
- Total system watts
- Fixed or portable panels
- Rigid or flexible panel types
- Series or parallel wiring configuration
- Total system amps
- System voltage
- Wire gauge used
- Controller type
- Personal pros and cons of your current setup
- What you might change in a future installation

These details will help establish baseline specifications for a fleet installation project. …more
Dometic RV Furnace Runs 10 Seconds Then Shuts Off - Complete Troubleshooting Guide
Propane Medium 1-2 hours 93 👍

Dometic RV Furnace Runs 10 Seconds Then Shuts Off - Complete Troubleshooting Guide

The YouTube tutorials I followed to fix my Dometic DFMD35111 furnace that runs 10 seconds then dies actually made it worse—now it won't even start! Every time I try to run it, the same thing happens - it fires up, runs for exactly 10 seconds, then just shuts off completely. This has been going on for weeks now and I'm getting desperate since the weather is getting colder.

I've been trying to troubleshoot this myself but honestly don't know where to start. I can hear the blower running and the unit seems to ignite initially, but then it just dies. Is this a common problem with these Dometic units? I'm really hoping this is something I can fix myself rather than having to call out an expensive repair tech.

What are the most likely culprits when a furnace runs for just 10 seconds then shuts down? I need to know what components to check first before I start taking things apart. …more
RV 12V Auto Reset Breaker Size Guide: 30A, 40A, 50A Selection
Electrical Easy 30 minutes 91 👍

RV 12V Auto Reset Breaker Size Guide: 30A, 40A, 50A Selection

Opened up my RV this morning to prep for our two-week cross-country trip tomorrow and the electrical system keeps tripping the breaker every time I run basic appliances! My RV's entire 12V system just died completely - no lights, no water pump, nothing. I've checked everything I can think of and I'm pretty sure it's the auto reset breaker that's failed.

I have a WFCO converter/charger setup with dual 6V batteries, but I can't get underneath right now to read what's stamped on the current breaker. I need to order a replacement but I'm not sure what amperage to get. I keep seeing 30A, 40A, and 50A options online but I don't want to guess wrong and either undersize it or waste money.

What's the typical auto reset breaker size for this type of setup? Is there a standard that WFCO usually pairs with dual 6V battery systems? …more
Thor ACE F53 Chassis Wheel Bearing Service & Propane Detector Replacement Guide
Electrical Medium 2 hours 90 👍

Thor ACE F53 Chassis Wheel Bearing Service & Propane Detector Replacement Guide

During my pre-trip inspection on my Thor ACE F53 chassis, discovered grinding wheel bearings and a dead propane detector that needs immediate replacement.

First, I desperately need to get my wheel bearings serviced/greased, but I'm having trouble finding someone who will work on them. Camping World told me they only service trailers, not motorhome chassis. I'm worried about driving much further without proper maintenance - where should I be looking for this type of service?

Second issue has me even more concerned: my propane detector started beeping constantly and wouldn't stop, so I had to pull the fuse. Now I discovered that with the fuse pulled, my slides won't operate at all! This seems like a safety feature, but I'm not sure if the detector just needs replacement or if there's a bigger problem. Are these systems really connected, and is it safe to replace the detector myself? …more
RV Alternator to Lithium Battery Charging: Complete DC-DC Wiring Guide for Safe Installation
Electrical Hard 4-6 hours 89 👍

RV Alternator to Lithium Battery Charging: Complete DC-DC Wiring Guide for Safe Installation

Last week I picked up my 2007 Holiday Rambler and discovered the previous owner left the alternator-to-battery charging system a dangerous wiring disaster that could destroy my new lithium batteries.

I'm upgrading from four 6V lead-acid house batteries to lithium, and I keep reading conflicting advice about alternator charging. Some people say "just connect it directly," others are warning about alternator damage and proper current limiting. I'm planning to add a DC-to-DC charger eventually, but I'm confused about whether I can safely use the alternator to charge lithium batteries in the meantime.

What's the right way to handle alternator charging with lithium batteries? Should I disconnect the alternator feed completely until I get a proper charging system, or is there a safe way to make this work without turning my alternator into an expensive paperweight? …more

Still stuck on this repair?

Get a personalized answer from a verified RV mechanic. Describe your issue and get step-by-step help.

Chat with an RV Mechanic
27708 RV owners helped · Avg response under 5 min
Can You Remove an RV Inverter Charger Without Replacement? (Yes, Here'
Solar Batteries Medium 3-4 hours 85 👍

Can You Remove an RV Inverter Charger Without Replacement? (Yes, Here'

Called three RV supply shops about replacing my failed Xantrex inverter/charger in my 2001 Fleetwood Expedition — but do I even need one or just wasting money? Since I never utilize the inverter function and rely exclusively on generator or shore power for 120V loads, I'm evaluating whether complete removal is feasible rather than expensive replacement.

My primary concern is maintaining proper 12V DC charging capabilities for house batteries that power lighting, water pump, and ventilation systems. Would installing a standalone battery charger provide adequate charging and maintenance functionality? Are there any critical system integration issues I need to address, particularly regarding power transfer switching between shore power and generator sources? …more
Suburban SF-30 Furnace Replacement: Complete Unit vs Core Guide for RV Owners
Propane Medium 4 hours 84 👍

Suburban SF-30 Furnace Replacement: Complete Unit vs Core Guide for RV Owners

Somewhere between our freezing mountain trip last month and now, my 2002 Born Free's SF-30 furnace died completely and I'm torn between replacing the core versus the whole unit. I believe it's a Suburban SF-30 model. I've been doing some research and see there are two options - I can buy a complete furnace replacement or just get a replacement core that supposedly slides into the existing SF-30 housing for about half the price.

I'm honestly not sure which route to go. The cost savings on the core is tempting, but I don't want to make the wrong choice and end up with more problems. As someone who's still learning about RV maintenance, would you recommend getting the complete unit or would the core replacement work just as well? Any guidance would be really appreciated! …more
Coleman 9420-381 RV Thermostat Voltage Drop: Complete Repair Guide & Solutions
Propane Medium 45 minutes 80 👍

Coleman 9420-381 RV Thermostat Voltage Drop: Complete Repair Guide & Solutions

Pulled the same wire swap trick that fixed my old analog RV thermostat's voltage drop, but this new Coleman 9420-381 digital replacement is behaving completely different. Everything worked great all summer with the AC, but now that heating season is here, I'm having major problems.

The furnace keeps short-cycling terribly - the burner fires for maybe 3-20 seconds, shuts off, then the whole cycle repeats. I've already ruled out the furnace itself (replaced the board, checked sail switch and limit switch). Through testing, I discovered the furnace is steady at 13.4V, but when the thermostat calls for heat, the voltage it sends back slowly drops from 13V down to around 10V, then the burner shuts down.

If I short the two furnace wires directly, the furnace runs perfectly. I suspect the thermostat's solid state components are failing. I'm wondering:
1 Has anyone else seen this issue?
2 Are others using this 9420-381 thermostat without problems?

I really like the digital features, but need a reliable solution. …more
Suburban KT30 Furnace 521099 Circuit Board Upgrade: Complete Wiring Fixes & Spark Troubleshooting
Propane Medium 2-3 hours 77 👍

Suburban KT30 Furnace 521099 Circuit Board Upgrade: Complete Wiring Fixes & Spark Troubleshooting

The multimeter's charged and screwdrivers are laid out — ready to fix this Suburban KT30 Furnace 521099 circuit board myself, just need the proper wiring sequence. I upgraded my Suburban KT30 furnace with the new 521099 circuit board and 528039 adapter harness after the original board failed. The good news is I now have power to the gas valve through the brown wire - that part's working!

But here's what's driving me crazy: when the gas valve opens, I'm only getting ONE spark at the electrode instead of the continuous 5-7 seconds of sparking I should be getting. I've been digging through wiring diagrams and realized the old board had a dedicated wire for the flame sensor, but the new setup just has me grounding that old flame sensor wire.

I'm pretty sure this flame sensor wiring issue is what's causing the single spark problem instead of continuous ignition, but I can't figure out how to properly wire it with this new 521099 board. Has anyone successfully done this upgrade and gotten the flame sensor circuit working correctly? …more
Suburban SF-42Q Furnace Shuts Off After 5-10 Minutes: Troubleshooting
Propane Hard 1-3 hours 75 👍

Suburban SF-42Q Furnace Shuts Off After 5-10 Minutes: Troubleshooting

Pulled into camp last night and there's this sharp clicking sound followed by dead silence when my Suburban SF-42Q furnace burner dies after 5-10 minutes. The system attempts to re-ignite several times before giving up and shutting down completely. Cycling power restarts the unit, but the same pattern repeats.

I've verified the sail switch operates correctly and the thermal limit switch shows continuity when cold. The unit starts immediately and heats effectively during those initial minutes before failure. What are the most likely causes for this specific shutdown pattern, and what diagnostic steps should I prioritize to identify whether this is an overheating issue, fuel delivery problem, or control board failure? …more
RV Furnace Won't Ignite But Blower Runs: Complete Troubleshooting Guide
Propane Medium 1-2 hours 75 👍

RV Furnace Won't Ignite But Blower Runs: Complete Troubleshooting Guide

Staring at my 2022 Thor Quantum SE28 furnace after following three YouTube tutorials that somehow made it worse — now it won't ignite despite the blower running perfectly. The unit is getting power and the blower motor kicks on when I call for heat, but I'm not getting any ignition at all - no flame, no heat output. I can hear the blower running strong, so it's definitely getting electrical power, but something in the ignition sequence isn't working.

I've got plenty of propane (3/4 tank) and my stove works fine, so I know gas is flowing to the RV. This is actually the first time I've tried to fire up the furnace this season after it sat unused all summer. The outside vents look clean and I don't see any obvious obstructions, but I'm wondering if there are specific components in the ignition system I should be checking.

What are the most common failure points when you have blower operation but no ignition? I'd like to work through the troubleshooting systematically rather than just throwing parts at it. Are there particular components like switches or igniters that typically cause this symptom? …more
2018 Chaparral Thermostat No Power: Complete RV Furnace Wiring Fix Guide
Propane Medium 2-3 hours 74 👍

2018 Chaparral Thermostat No Power: Complete RV Furnace Wiring Fix Guide

Thermostat screen is completely dead — no display, no backlight, nothing. Furnace won't kick on and it's getting down to freezing tonight. Checked the fuse panel and everything looks good. Starting to think the thermostat wiring itself has a break somewhere in the wall. …more

Need a second opinion?

Not sure if this applies to your rig? An RV technician can confirm the fix for your specific make and model.

Ask an RV Expert
27708 RV owners helped · Avg response under 5 min
Suburban SH-42 Heater Wiring Diagram: Complete Thermostat Connection Guide
Electrical Medium 30-60 minutes 72 👍

Suburban SH-42 Heater Wiring Diagram: Complete Thermostat Connection Guide

Around two days before our two-week camping trip, I discovered my Suburban SH-42 propane heater's new thermostat wiring might be completely wrong. The unit was experiencing starting issues prior to the thermostat replacement, and I want to ensure proper circuit continuity.

What is the correct thermostat wiring configuration for the SH-42, and what is the proper procedure to test the thermostat circuit to confirm the connections are functioning correctly? I need to determine if the issue is with the wiring connections or potentially the new thermostat itself. …more
Micro-Air 355 Thermostat Wiring Issues: Multi-Zone RV HVAC Troubleshooting Guide
Electrical Hard 2-4 hours 71 👍

Micro-Air 355 Thermostat Wiring Issues: Multi-Zone RV HVAC Troubleshooting Guide

Around the third day into our trip, my Micro-Air 355 thermostat has zones not responding, temperature readings jumping randomly, AND the whole system cycling on and off every few minutes all at once. I replaced my old RV Comfort.ZC thermostat with a Micro-Air 355 and nothing is working right. The old thermostat controlled both zones perfectly, but now I've got a complete mess.

My current wire connections include:
- Red 12v in *
- White 12v out *
- White B-
- Green SIG 1 *
- Brown SIG 2 *
- Red R+
- Blue B-
- Yellow R+ (not used on old thermostat)

Zone 1 cool doesn't work AT ALL, but the furnace works fine. Zone 2 is backwards - cool works but furnace won't kick on. Even worse, once I switch from zone 1 to zone 2, I can't get back to zone 1! I have to reset the whole thing.

I've got these extra yellow and orange wires that were showing voltage when zone 2 furnace should be running. My Coleman Mach units are fine - this has to be a wiring difference between the thermostats. I really thought this would be plug-and-play! Is there something specific about how the Micro-Air 355 handles SIG1 and SIG2 wires differently than the RV Comfort.ZC? I'm starting to think I need professional help with this multi-zone setup. …more
Robert, RV Mechanic
Ask an RV Mechanic Avg reply < 5 min

My Rig Settings

Hi, I'm Hank!
Need help setting up? I can walk you through it
Rig Info
Give it a name you'll recognize
Power & Electrical
Climate Control
Water System
Refrigerator Type
Leveling System
Convenience & Features
Sync across devices