MHUniversity Vent Free Heaters

The Vent Free Heaters come in radiant or blue flame indoor safe wall-mountable heaters that run off of either propane or natural gas. This heater is the perfect supplemental heating solution even on the coldest days. It is equipped with a multi-output valve for easy temperature regulation and a convenient piezo ignition built right into the rotation of the knob for one handed ignition. This unit can be permanently mounted to the wall or securely fastened to the floor with included mounting brackets and fasteners. With a factory standard Oxygen Depletion Sensor (ODS), rest assured this heater will provide you with years of comfortable and safe heat.

Page Contents

Vent Free FAQs
Vent Free Manuals and Troubleshooting Guides
Vent Free Radiant Heaters
Vent Free Blue Flame Heaters
Vent Free Garage and Ice House Heaters
Vent Free Accessories
Parts Ordering

Vent Free Heater FAQs

What is an ODS?

An ODS is an Oxygen Depletion Sensor. This device senses the amount of oxygen in the air surrounding the device. When the oxygen level drops below a specific level, the device will shut off automatically.

Was this helpful?

Why doesn't my heater come with a hose and/or regulator?

Your heater may not include a hose and/or regulator because it is not required for the product to function. Or there may be multiple options available in regards to the length of the hose, what length you need, etc.

Was this helpful?

What does the heating area square feet mean?

Square footage is the length of an area times the width of an area. Knowing the square footage of an area allows you to estimate the amount of BTUs necessary to heat the area most effectively. A generally accepted formula is: Square Footage x 40 = required BTUs. This is just a starting point. Ceiling height, building layout, and level of insulation will also factor into your BTU needs.

Was this helpful?

What is W.C. (Water Column) and how do I measure it?

All gases are measured in W.C. because it is used to measure small differences in low pressure across an orifice or pipeline. Low pressure is any pressure below 1 Pound per Square Inch (PSI). When dealing with pressures below 1 PSI, you will see the term inches or inches of water column. This refers to the amount of pressure it takes to raise a column of water 1 inch. There are 27.7 inches of water column (W.C.) pressure in 1 PSI of pressure. W.C. is measured with a manometer (pressure gauge), which measures the pressure of gases and vapors. If you need to measure your W.C., we highly recommend you contact your local gas company to send out a professional or have someone who is HVAC certified to test it.

Was this helpful?

I push in the igniter button, but get no spark?

The battery is missing or low or the igniter electrode or connection to it might be broken.

Vent Free Batter Location

Was this helpful?

Why does the pilot light go out when the control valve is released?

Clean pilot assembly. If the flame still goes out, replace pilot assembly.

Pilot Light Assembly

Was this helpful?

What are the Thermostat settings?

Setting 1: 60.8 F
Setting 2: 75.2 F
Setting 3: 89.6 F
Setting 4: 104.0 F
Setting 5: 118.4 F

Vent Free Thermostat

Was this helpful?

Why does this heater produce unwanted or bad odors?

Hair spray, glues, cleaning agents and other types of products can produce fumes that can be changed when drawn into the heater while it is in operation. Try airing out room to see if smells go away.

Was this helpful?

Why does condensation or moisture develop on my windows or walls?

The room needs more ventilation or air circulation. The process of burning propane also produces water vapor.

Was this helpful?

What is the elevation limit for these heaters?

The elevation limit is 4500ft. It is not guaranteed to work past that.

Was this helpful?

What is the difference between Radiant and Blue Flame? Which is better?

Radiant is Infrared style heat, which is when the glow from the heater will heat an object in the area. For example, the sun is radiant heat. The heated objects then release the heat into the surrounding area. Blue Flame is Convection style heat, which is when the flame heats the air around it. For example, your home Furnace. It is heating the air moving through it and pushing that warm air into the rooms. When it comes to which is better, it is personal preference. Generally if you have a lot of objcts in the room your heating, Radiant heat would most likely be a better option. Open rooms would be more suired to the Blue Flame heat as there is more air movement.

Was this helpful?

Do I need an external regulator on this heater?

Yes, you need a .5 PSI regulator on the tank that should produce 11in-14in W.C. (water column). The regulater inside the heater is for the pilot only and controls the flame when kicking on/off. An external low pressure regulator is sold separately. We have multiple low pressure regulators available on the site. Click here for a listing.

Was this helpful?

What safety features does the vent free heaters have?

The Vent Free heaters have two saftey features. The thermocouple which closes the gas valve if no flame is sensed. And the ODS (Oxygen Depletion Sensor) which will shut the heater down if the O2 levels in the heated area go below 18%.

Was this helpful?

Can these heaters be converted between gas types?

Unfortunately, no. These heaters are set up to run either Propane only or Natural Gas only. There are no availible conversion kits.

Was this helpful?

What accessories do I need to install this heater?

For connections to smaller propane tanks (20lb or 40lb), you will need a 3/8in adapter fitting, a 3/8in fitting hose, and a .5 PSI regulator. There are multiple options on our site for each item. If you are hooking directly to a gas line, you will need to contact your gas company. Then you would also utilize the One Stop" Universal Gas kit to complete the connection. Click here for part number F271239."

Was this helpful?

What is the benefit of purchasing the blower fan?

This accessory is not a required item but is useful to push the residual heat away from the top of the heater.

Was this helpful?

What is the pressure required to properly run this heater?

The proper pressure for a Propane heater (either blue flame or radiant) is 11in-14in W.C. (water column) [1/2in PSI] and for a Natural Gas heater (either blue flame or radiant) is 5in-7in W.C.

Was this helpful?

The room gets too hot at the lowest setting. Can the thermostat be adjusted beyond the manufacturers setting?

Unfortunately you can not adjust the Capillary Tube that is set up with the thermostat valve assembly for specific heat settings. This high level of heat could be caused if the wall that the heater is mounted to is too cold and not allowing the Capillary Tube to heat up to shut off the valve. If this is not the issue, please contact our Technical Support and we will walk you through additional troubleshooting.

Was this helpful?

There are blue flames coming out of one of my tiles. Is this ok?

A little bit is okay, but if it is more then a 1/4in, you need to turn the gas pressure down about a half a W.C. Inch (Water Column) until the flames stop.

Was this helpful?

Is this heater adequate to use as a permanent heat source?

No, these heaters are meant for auxiliary heat to help supplement your rooms that need the chill taken out. These heaters are not meant to run continuously or unattended.

Was this helpful?

My heater has started giving off a bad smell?

There are different types of chemicals that, when drawn into the heater during its burning will react with the propane and make some disagreeable odors. The propane supplier may have added more of the odorizor called Mercaptan to the propane. First try the heater in a different area where no chemicals are used to see if the smell goes away and also try a different propane tank.

Was this helpful?

Can I purchase these in Canada? Or California?

No, vent free are not approved for sale in either California and Canada.  Both locations have restrictions on gas heating products being used indoors (especially dwellings).  Please always refer to your local codes before purchase as they may vary from state mandates.

Was this helpful?

Do you need to order parts?

For your convenience please enter your serial number below to access Mr. Heater’s interactive schematic & parts ordering system. This system will allow you to browse your specific product schematic to order the correct service parts as well as download a complete manual for your make & model year.  If your product was produced any year prior (2011 and earlier), please call our Service Department at 1-800-251-0001, where our technicians will gladly assist you.


Was this helpful?

Don't see your question?

We try to make our FAQs as comprehensive as possible but sometimes things are missed!  We apologize for the inconvenience and ask that you contact us so we may assist you.  You have multiple options to get a hold of us:

1. You can click the "No" below to the question "Was this helpful?" and that will send your question to our Technical Department where someone should respond within one business day.

2. You can call us at 1-800-251-0001 (USA & Canada) during our business hours (standard 8AM EST - 5PM EST but vary during seasons and holidays).

3. You can fill-in the Contact Us form on the Contact Us page and someone should email or call within one business day.

We appreciate you taking the time to give us your feedback and help us imrpove our site!

Was this helpful?

Go to top

Vent Free Heater Manuals and Troubleshooting Guides

Go to top

Go to top

Go to top

Go to top


Go to top

Parts Ordering


Go to top