Regulator Needed For A Mr. Heater Big Maxx 50,000BTU Garage Heater

Updated 12/15/2025 | Published 11/14/2024

Question:

I’m installing a 50,000 btu Mr Heater wall mounted propane heater. I have a 200 gallon propane tank that will be feeding it. What size regulator should I use?

asked by: John

Expert Reply:

Hey John,

The manual for the Mr. Heater Big Maxx states that if using natural gas you'll need to maintain 7" W.C. of pressure and if your using Liquid Propane (LP Gas) then you'll need to maintain 13" W.C. of pressure in order for the unit to properly operate. The other factor to consider here is the BTU input for the unit, which for this one would be 50,000BTU's.

You essentially just want to make sure you can meet the pressure and BTU requirements of the unit so if you were going to connect this heater to LP Gas you could use a 2-stage regulator like # 108221 (horizontal) or # 108220 (vertical) depending on how you run the piping. These regulators have vents built into them that you'll need to face down, hence the vertical or horizontal options. These are set at 11" W.C. so you'll need to have a qualified technician adjust the pressure up to 13" W.C. to meet the pressure requirements. They are both rated for up to 400,000 BTU's per hour so they more than cover that requirement.

If you go with natural gas you'll need to pick up a low pressure natural gas regulator from your local hardware store since we only deal with LP Gas. You'll likely also need to have a technician adjust the pressure to 7" W.C. since it'll probably be set in the middle of the range and these typically have a 7" to 11" range to work with.

expert reply by: Kevin C

Kate F.

12/15/2025

Hey John, how did things go getting your Mr. Heater wall-mounted propane heater set up with the regulator? Your update could make it easier for others working with a similar BTU setup and tank size.