Popular New Guides Product Guides Tools Checklists My Rig

Results for "furnace cycling"

783+ Q&A Updated Weekly Free
Atwood AFMD35 Furnace Playing Peek-a-Boo - How to Clean Flame Sensor & Fix Short Cycling
Propane Medium 30-60 minutes 95 👍 1

Atwood AFMD35 Furnace Playing Peek-a-Boo - How to Clean Flame Sensor & Fix Short Cycling

Staring at my Atwood AFMD35 manual that claims it should stay running once lit, but mine keeps shutting off every few minutes like it's playing peek-a-boo. It fires up beautifully for about 5-10 seconds, gets my hopes up that I won't freeze tonight, then promptly shuts off like it's having second thoughts about this whole "heating the RV" thing.

I've ruled out the sail switch and high temp limit since it actually lights (small victories in RV life, right?). I'm pretty sure the flame sensor is the culprit here, but I've never cleaned one before. How do I clean this mysterious little part, and what's the best way to access it on this model? Because apparently my furnace thinks playing hard-to-get is charming! …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
Suburban RV Furnace Won't Work on Shore Power - Complete Fix Guide
Propane Medium 2-3 hours 88 👍

Suburban RV Furnace Won't Work on Shore Power - Complete Fix Guide

Around midnight in the RV parts aisle staring at furnace components with no clue why my 2016 Heartland Bighorn's Suburban furnace acts totally different on shore power versus battery. When I'm running off battery power, the thing works like a champ - fires up, heats great, cycles on and off perfectly.

But the second I plug into shore power? It's like the furnace forgets how to do its job. It'll run for about 4 minutes, never actually produce heat, then shut off and lock out until I reset everything. The only way to get it working again is to disconnect shore power and cycle the battery.

I'm wondering if this is some kind of converter problem? Like maybe it's sending the wrong voltage to the furnace control board when on shore power? Has anyone run into this before and know what voltage levels I should be checking? …more
RV Lithium Batteries: Dual Purpose vs Deep Cycle for Coach House Banks & Performance
Solar Batteries Easy N/A - informational 84 👍

RV Lithium Batteries: Dual Purpose vs Deep Cycle for Coach House Banks & Performance

Despite watching countless YouTube videos on RV lithium batteries, I'm now more confused than when I started about dual purpose versus deep cycle for my motorhome's house bank. I understand that dual purpose batteries are designed to handle both starting and deep cycling applications, which sounds convenient for an RV setup. However, I'm wondering if there are performance trade-offs when using dual purpose lithium batteries specifically for coach/house battery applications where they'll primarily be doing deep cycling to power lights, water pump, refrigerator, and other 12V systems. Would I be better off with dedicated deep cycle LiFePO4 batteries for my house bank, or do dual purpose lithium batteries offer sufficient performance for typical RV boondocking and daily use? I want to make sure I'm getting the best cycle life and value for my investment in a house battery system. …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

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
RV Heat Pump Amp Draw: How Many Amps Does Your Unit Use?
Ac Refrigeration Easy 30 minutes 76 👍

RV Heat Pump Amp Draw: How Many Amps Does Your Unit Use?

Turned down a Class A with a heat pump because I'm terrified of being that neighbor constantly tripping breakers — am I overthinking this? We're plugged into 30-amp service at home while I pretend to know what I'm doing with all these fancy RV features.

Basically, I need to know how many amps this heat pump is going to suck down when it kicks on. I'm already running the usual suspects - fridge, lights, maybe the TV so I can ignore my responsibilities - and I'd rather not find out the hard way that I'm overloading everything. Anyone know the typical amp draw so I can at least look semi-competent when explaining to my spouse why the power keeps cutting out? …more
Airxcel Furnace Not Working When Thermostat Switched to Heat
Propane Medium 45 minutes 75 👍

Airxcel Furnace Not Working When Thermostat Switched to Heat

Looked everywhere for answers but my 2019 Forest River with an Airxcel furnace won't kick on when I switch the thermostat to heat mode. When I turn the thermostat to heat mode and adjust the temperature setting, absolutely nothing happens - no sounds, no fan activation, no ignition attempts, nothing at all. The unit was working perfectly fine last month during our camping trip, but now it's completely dead when I try to activate it through the thermostat.

I've tried adjusting the temperature settings both higher and lower, checked that the thermostat is properly set to heat mode rather than cool or off, and even tried turning the system off and back on again. The thermostat display appears to be functioning normally and shows the temperature settings I'm selecting, but the furnace itself shows no signs of life whatsoever. I'm wondering if this could be an electrical issue, a propane supply problem, or something with the connections between the thermostat and the furnace unit itself. …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
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
Dometic RV Furnace Flame Lights Then Dies: Complete Fix Guide 2024
Propane Medium 1-2 hours 72 👍

Dometic RV Furnace Flame Lights Then Dies: Complete Fix Guide 2024

My Dometic DFMD35111 furnace does the same infuriating thing every fall — lights perfectly on startup then immediately dies out. The flame lights up no problem, but then it just dies out randomly - sometimes after like 3 seconds, other times it'll run for several minutes before cutting out. It's totally unpredictable.

I've already cleaned out some bugs from the burner area and messed with the sail switch, but it's still doing this intermittent thing. The flame sensor looks pretty gunky though. Could that cause these random flame failures? And what else should I be checking when the burn time is all over the place like this? …more
RV Heat Pump Electric Heat Not Working: Complete Troubleshooting Guide for RV Owners
Ac Refrigeration Medium 1-2 hours 70 👍

RV Heat Pump Electric Heat Not Working: Complete Troubleshooting Guide for RV Owners

I'm planning a two-week cross-country trip that starts this Friday and my RV heat pump's electric side just completely died while the propane still works fine. What are the most likely causes when only the electric side fails? I need to know what components to check and test - things like heating elements, relays, or thermostat issues. What's the proper troubleshooting sequence for this problem? …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