How To Prime A Oil Furnace? Expert Tips And Tricks

In this blog post, we will know the process of how to prime an oil furnace in detail.

What is priming an oil furnace?

Priming an oil furnace is the process to draw oil from all corners of the furnace system and send it to the vapourize compartment before the engine starts.

How to prime an oil furnace?

Here are the key steps.

  • Locate the oil tank and the bleed screw or valve on the fuel pump.
  • Release any trapped air in the fuel line.
  • Check if there’s enough oil in the tank with a fuel gauge and top it up if not.
  • Switch off power at the thermostat and circuit breaker.
  • Press the reset button on your furnace.
  • Attach a tubing onto the bleeder valve and open it with a hex nut wrench/flat-head screwdriver, with a bucket below to capture any fuel drops.
  • Turn on your furnace and open the bleeder valve until only pure fuel flows.
  • In unique cases, install a filter to avoid stoppage/blockages.

Steps for Priming an Oil Furnace

To get your oil furnace primed up, you’ll need to take a few steps. 

Here’s how it’s done:

Locate the Bleeder ValveIt’s usually on the pump or burner assembly. This lets air escape when priming.
Bleed Air from the Fuel LineUse a wrench and put a container under it. When you see oil coming out without bubbles, close the valve.
Restart & Monitor FlowPress the reset button. Keep an eye on your oil gauge to see how it’s doing.

Troubleshooting Common Problems

Oil furnaces can have issues for many reasons. 

Here are the most common:

  • Fuel tank or line trouble.
  • Air clogs the line from the tank to the pump.
  • The igniter or ignition system not working.

But, if you can’t fix it yourself, get a certified HVAC contractor to help you.

Calling in a Professional HVAC Contractor

These trained pros have the knowledge to fix what DIY solutions can’t. Leave complex solutions to the experts. They’ll save time and money by finding and tackling any hidden problems.

A contractor can explain how to fix specific furnace problems. They’ll also tell you when to replace parts or the entire system. These specialized service guarantees repairs are done right, safely, and quickly.


Now you can prime your oil furnace without relying on an HVAC contractor. Bleed the air out of the fuel line with a bleeder valve and fuel pump. Make sure the flow is smooth. Check your oil tank for sludge and ensure the fuel lines are clean.