3 Prominent Reasons Why RV Furnace Runs with Thermostat Off

In the fewest words possible, an RV furnace runs normally to heat up the air and distribute it through the whole interior of your recreational vehicle. But what if the RV furnace runs with thermostat off?

Issues with the thermostat lead’s shortage, relay, and control board are common and prominent reasons why your furnace is running when the thermostat is off. A defective thermostat often causes the same bummer, and that’s when the replacement is the single solution!

Not every problem can be solved by following the same criteria. Sometimes, you can do it yourself by manual observation, while other times, you’ll need to take experts’ support. So let me disclose how to overcome each solution permanently.


RV Furnace Runs Even With Thermostat Off: Quick Chart 

In a rush? Well, go through the following chart, where I shortly discussed the prominent reasons along with their quick solutions: 

Defective thermostatGo for the replacement.
Thermostat lead’s shortageCheck manually through a multimeter or change the blown-out fuse.
Bad relay and control boardManually check these parts or consult a mechanic for detailed observation.

3 Reasons Why RV Furnace Runs with Thermostat Off and How to Solve Them:

Have you noticed the issue “furnace runs with thermostat off” for the first time? Unfortunately, there is no single way to fix such a problem as it occurs for a couple of reasons. 

So here, I’ll walk you through some noticeable reasons why your RV furnace is running, yet the thermostat is off! For your convenience, I’ll share some quick fixing methods right here –

1. Defective Thermostat 

Most probably, you’re having a hard time with your RV furnace due to the damaged thermostat. Issues with aging, rust build-up, and corrosion are known to be the 3 main culprits behind a defective thermostat. 

If any of the following signs appear in your thermostat, then it’ll start malfunctioning or get turned off, even if the furnace is running constantly!

So, replacement would be the solution to succeed in dealing with a bad thermostat. The cost might be around $ 110-$255 or so, depending on the brand and type.

Read Also: What To Do When Rv Furnace Clicking But Not Lighting?

2. Shortage on Thermostat Leads 

Due to inappropriate and poorly connected wires, there is a chance to end up with shorts on your thermostat leads. And that’s when the problem with “furnace runs yet thermostat off” comes in!

Sometimes, the white wire turns short on account of the blown-out fuse. In such a case, replacing the fuse becomes a “must!” 

In order to confirm whether the problem has appeared for short in the thermostat or not, get yourself a multimeter and identify the real cause. Call an expert if you fail to do so. 

3. Poor Relay & Control Board 

As you know, most interior parts or components of your RV are connected to each other. In a similar way, the relay and thermostat maintain a decent attachment through wiring. 

Consequently, when the thermostat is off, and the furnace is still running, you shouldn’t neglect to observe the relay particularly. In a word, most of the relays stand on the BCC (battery control center). 

After paying attention to that spot, you may find it damaged or blown out. Consult labor to change the bad relay, where he will charge up to 37 dollars. As for the cost of the components, it is not more than $75 for an average RV.   

Speaking of the control board, it’s more like a complex component that can’t be examined by fresher RV users. So I’d highly prefer talking with the manufacturer about it for further queries.

Read Also: Where Is Suburban Rv Furnace Reset Button And How To Reset?

Why Does My RV Furnace Run with Generating No Heat? 

Despite running the RV furnace, are you noticing no heat inside your RV? Well, since it’s a common issue for some RV furnaces, you better go through the probable reasons why it can happen –

  • Probably the control circuit board gets defective or requires fixing. 
  • The sail switch might turn faulty or get stuck. 
  • Perhaps the regulator or thermostat is in need of a replacement. 
  • Pay attention to the burner, as it can be corroded or damaged. 
  • Any of the parts mentioned above might turn rusty or corroded. 

No matter what the reason is, you need to stick with your manufacturer’s instructions to solve the issue once and for all!

Read Also: Where is Atwood Furnace Reset Switch & How to Reset?

Frequently Asked Questions 

Let’s read on the questions listed for those who have more queries about the RV furnace runs but the thermostat off. The answers are based on the users’ experiences and my personal views:

Is it worth spending on a new thermostat if it stops working even when the furnace is okay? 

Of course, it does! In fact, some problems related to the “furnace running but the thermostat off” are totally unfixable without replacing the thermostat. Especially if it gets worse due to aging, corrosion, and rust build-up!

Why does my RV furnace keep running all the time? 

Paying attention to the ICU (Ignition Control Unit), sail switch, and the gas-controlling valve is a must to detect why your RV furnace keeps running. Any of the parts might have gone bad, which is why the fan will always run without offering any heat!

Despite my thermostat being off, why does the RV furnace keep starting and stopping?

Because of the technical glitch, the thermostat tends to receive inaccurate readings from the system. And thus, it becomes unable to point out whether the furnace is stopping or starting.
In such a case, go for a technician to detect your thermostat’s current condition. 

Even if the thermostat is off, why does my RV furnace make an annoying sound while running? 

There is nothing wrong with your thermostat if you notice annoying sounds coming from your RV furnace. Instead, check the fan’s bearing to confirm whether it has loosened or ruined.
Sometimes, blades are prone to rub against the housing of the fan and make noises!

Read Also: Why Suburban RV Furnace Won’t Light At Extreme Temperature?

Wrapping Up! 

As per my research, most issues concerning “RV furnace runs when the thermostat off” occurs for the defective thermostat. Sometimes, the thermostat loses its actual resistance. Or let’s say it has gone completely worse by aging or rusting. 

But guess what? The replacement has still been the most effective way to solve such an issue. Luckily, that isn’t going to be costly and not so tough at the same time!

However, I’d always prefer discussing the manufacturer of your RV if you face such an annoying situation. I guess he will suggest the safest thing to do in order to overcome the fact and further inconveniences. So, what’s the delay?

Read Also: Why RV Furnace Shuts off After 30 Seconds & How to Fix it?

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