Frequently Asked Questions

What is the difference between vented and ventless heating?

Vented heating requires ventilation to the outside, either through piping or a damper in an existing fireplace.

Vent-free also known as Ventless heating does not require ventilation. ProCom does not guarantee their Vent-Free products to operate correctly above 4500 Ft. above sea level. Customers may experience pilot outages and performance problems with the product.

Both types of heating are safe provided the specific unit has been certified and installed according to the manufacturer’s instructions.

Are Ventless gas products safe to use the home?

Yes, most states in the US allow for the sale and installation of vent-free “supplemental” gas heat appliances.

ProCom Ventless products are equipped with an ODS pilot assembly, precision-engineered burners for clean burn and a non-adjustable regulator to prevent over-firing. The purpose of the ODS is to shut off the supply of gas to the heater/fireplace when the oxygen level drops below 18%.

All major building codes categorize vent-free as “supplemental heat”. Local codes may vary. California does not currently permit the use of vent-free installation. For more information refer to:

What is the difference between Blue Flame and Infrared?

Blue Flame Wall Heater

Blue Flame

Heats like a central heating system – heating the air first and then circulating warmth throughout the room, the hot air rises

May take longer to heat the room as it works to “convect” the entire area.

Typically work better in insulated areas

Infrared Wall Heater

Infrared (Plaque)

Heats like the sun, radiating warmth, directly heating the objects in the room first, heating outward.

Feels more like standing in front of a fire

Typically works better in un-insulated areas as they will heat objects before the air.

What is the difference between a dedicated gas product vs. dual fuel?

Dedicated products are manufactured with parts engineered specifically for either natural gas or propane (LP) and cannot be converted from one gas to another.

Dual fuel products offer the choice of using natural gas or propane (LP)

Can I convert my ventless (Vent-Fee) dedicated fuel unit for one gas type to another?

ProCom does not offer any conversion kits and converting may void the manufacturers’ warranty on gas specific products

What are the restrictions for Ventless NG?

Natural gas from the ground is odorless. The characteristic “gas” odor is added afterwards by the supplier called “mercaptan”, containing sulfur, which will give it the characteristic “rotten egg” odor.

NG units cannot be connected to a private (non-utility) gas well, also known as “well-head” gas. These are typically found in rural areas where there is not an access to utility owned gas lines. This gas is odorless, therefore unsafe because a leak cannot be detected quickly.

What type of regulator is required outside for a LP appliance?

Regulators are sized to the appliance, not the container you are connecting to. There are three (3) key pieces of information:

  • BTU Load of the appliance
  • Operating pressure of the appliance (W.C. 11”-14” of water column pressure)
  • The required inlet and outlet pipe size. ( Refer to Troubleshooting Section)

The “Integral Twin Stage System” is the most common for residential installations. If the propane tank is 15’ or more from the appliance, a “Two-Stage System” is recommended because of the propane required for the appliance to run correctly and efficiently.

Integral Twins

Integral Twins

Two Stage System

Two Stage System

What size LP tank is required for ventless gas products?

The minimum requirement is a 100 lb. tank. If a smaller tank is used the propane liquid does not have enough pressure to vaporize, the heater may begin to run improperly. This can also damage the internal regulator.

The amount of propane gas ready for use from propane tanks varies. Two factors decide this amount:

  • The amount of propane gas in tank(s)
  • The temperature of tank(s)

The colder the outside temperature, the slower the vaporization rate of the propane, the LP inside the tank will not vaporize fast enough to operate the appliance and will create frost on the outside of the tank and cause the unit to shut down due to the lack of fuel.

IMPORTANT: The only exception is the ProCom Ice House Heater, which uses a minimum 20 lb. tank.

What does the term“BTU” mean?

A “BTU” is a British Thermal Unit. BTU is the amount of energy it takes to raise one (1) pound of water one-degree Fahrenheit.

  • 1 BTU = the heat generated by 1 lit matchstick.
  • BTU limitations based on the cubic feet of air available in an area.
  • Manifold pressure and orifice size determines the BTU output of the burners.

Wall Heaters and Stoves:

To calculate the maximum BTU’s allowed for an area, follow this formula:

Room Width X Room Length x Room Height x 20

Example: 10 ft. x 20 ft. x 8 ft. =1600 sq. ft.

1600 sq. ft. x 20 = 32,000 (maximum)

Insert Measurements

Gas Logs and Fireplaces Inserts:

The maximum BTU’s for a fireplace or insert varies depending on whether the unit is ventless or vented.

The maximum BTU’s allowed set depends on: Front Width – Depth – Height

Front Width: 24” (Rear Width: 18”) – Depth: 15” – Height: 18”

Space for 18″ Vented Log Set

PFA, GFA, Construction & Tank Top Heaters:

Cu. Ft. of Area x .133 x Desired Temp. Rise °F = BTU Size Needed

Example: Area: 50′ x 25′ x 10′ = 12,500 Cu. Ft.

Desired Temp. Rise: 30°F 12,500 (Cu. Ft.) x .133 (Factor) = 1662.5

1662.5 x 30 = 49,875 (50,000)

What is a Vent-Free Firebox?

A Ventless Firebox has “zero” clearance which means these units:

  • Can be placed on the floor without footings.
  • Can be finished up to the face of the fireplace, so that no metal shows after installation is complete

For installation requirements and further information refer to the Owner’s/Operator and Installation Manual.

What are the installation requirements for vent-free heating?

In order for an installation to be compliant with Federal Codes, all ProCom units are required to be installed by a licensed heating contractor, according to all local codes. The Owners’ Manual States that only a qualified agency should install and replace gas piping, gas utilization equipment or accessories, repairs and equipment servicing.

The term “qualified agency “means any individual, firm, corporation or company that either in person or through a representative is engaged in and is responsible for:

  • Installing, testing or replacing gas piping
  • Connecting, installing, testing, repairing or servicing equipment; experienced in such work; familiar with all precautions required; and has complied with all the requirement of the authority having jurisdiction.

Note: Massachusetts requires Board of State Examiners of Plumbers’ approval before installation. For specific ProCom codes refer to:

Where can I install a Ventless or Vent Free heating product?

Never install the heater:

  • Over 10,000 Btu/Hr in a bathroom
  • Over 6,000Btu/Hr in bathroom (Check local codes.)
  • In a recreational vehicle
  • Where curtains, furniture, clothing, or other flammable objects are less than 36″ from the front, top, or sides of the heater
  • In high traffic areas
  • In windy or drafty areas

Important: Please check your local and state codes for vent-free appliance installation.

Please review the owner/operator Installation manual for a specific model.

What are the altitude restrictions on Ventless or vent-free heating?

Manufacturers of vent-free appliances typically to not recommend not using their products above 4500 –5000 FT. The higher the altitude may cause pilot outages, due to the incomplete combustion of the gas caused by the low oxygen level. Vented heaters are adapted for use at a higher altitude.

What type of certification is required?

ProCom vent-free heating products are certified by Product Fabrication Services (PFS) and meet the National Safety Standard ANSI Z21.11.2-2002 and ANSI Z21.11.2a-2003. The companies that complete this testing for ProCom are:

  • Canadian Standard Association (CSA) – Canada & US
  • Product Fabrication Service (PFS)
  • Omni – Test Laboratories (O-TL)

This certification can be found on the front of the owners’ manual, product hang tags, or the labels on the units. Note: Underwriters Laboratory (UL) does not certify gas products. They only certify electric products.

What is “Water Column Pressure” (W.C.)?

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.

Pressure Graph

  • 7.0″ W.C. = approx. ¼ lb. PSI
  • 13.5” W.C = approx. ½ lb. PSI

Regulator W/Plunger

  • For LP: Unit needs 11.0” – 14.0” W.C.
  • For NP:

No-Step Regulator

  • For LP: Unit needs 11.0” – 14.0” W.C.
  • For NP:

Note: The maximum pressure in a residential dwelling is 2 psi. ProCom units are low-pressure systems. For NG, an additional meter maybe needed if dwelling is on a 2 psi systems.

What is a “Oxygen Depletion Sensor” (ODS)?

All Ventless or Vent-Free appliances are equipped with an ODS pilot assembly. The purpose of the ODS is to shut off the supply of gas to the heater/fireplace when the oxygen level drops below 18%.

During operation, if the pilot flame goes out for any reason, the thermocouple or thermopile will cool and shut the gas valve that supplies the supply to the burner, shutting down the heater. There must be adequate air ventilation for units to function properly.

ODS system contains a precision orifice. This ODS has a “ruby” orifice and designed to disintegrate with any attempt at drilling it out to enlarge the pilot flame. Additionally, it is not interchangeable with a normal standing pilot. Trying to burn gas at extremely low oxygen levels can cause deadly gases and high levels of Carbon Monoxide.

Normal Operation

Normal Operation 20.9% Oxygen

Pilot flame engulfs tip of the thermocouple, generating the millivoltage needed to hold the safety pilot valve open.

Oxygen Level Dropping

Oxygen Level Dropping 19 % Oxygen

The flame begins to lift-off the precision pilot burner, causing the thermocouple to cool.

Safety Shutdown

Safety Shutdown 18% Oxygen

The unstable pilot flame moves away from the thermocouple causing the thermocouple to stop generating the electricity needed to hold the spring loaded safety valve open. The flow of gas stops

What is “Carbon Monoxide” ?

Carbon Monoxide (CO) is measured in parts-per million(ppm) An average cigarette emits 60-ppm draw or drag. Vent-Free products emit only 8ppm of CO over a three (3) hour period. Occupational Health and Safety Associaton (OSHA) considers air quality at 200 ppm of CO to be unsafe. Vent-Free appliances are 99.9% efficient and are safer to operate than a gas range.

Carbon Monoxide Level of Toxicity:

  • 200 ppm > Slight headache within 2-3 hours.
  • 400 ppm > Frontal headace with 1-2 hours, becoming widespread in 3 hours
  • 8400 ppm > Dissiness, nausea, convulsions within 45 minutes, insensible in 2 hours.

Vent-free products are AGA approved, therefore certified to conform to National emmissions Standards. A Carbon Monoxide detector is not required for product installation.

What is “water vapor” and it’s relation to vent-free heating?

Water vapor is a by-product of gas combustion. An unvented room heater produces approximately one (1) oz. (30ml) of water every 1,000 BTU’s (.3KW’s) of gas input per hour. Unvented room heaters are recommended as supplemental heat rather than primary heat source. In most supplemental heat application, the water vapor does not create a problem. In most applications, the water vapor enhances the low humidity atmosphere experienced during cold weather.

The following steps will help insure that water vapor does not become a problem:

  • Heater sized properly for the application, including ample combustion air and circulation air.
  • Experience high humidity, a dehumidifier may be used to help lower the water vapor content of the air
  • 8400 ppm >Do not use an unvented room heater as the “primary heat source”

Example: Vapor (sweating) on windows or walls – unit is too large for the area.

What is causing a strong “odor” when my unit is burning?

Vent-Free products typically produce an odor during initial operation. This will subside after 2-8 hours burn time. Determine what kind of odor (most of the time it is not a gas leak but impurities in the air). The following are examples that can affect new and existing installation:


Improper log placement

Chemical impurities introduced to the environment such as:
– Paint
– Furniture polish
– Odor from garage
– “Off” gassing from new home construction
– Christmas trees
– Odor from basement
– Air fresheners
– Cleaning chemicals
– Shoe polish


Gas Leak: Shut the unit off. Licensed plumber or the gas company needs to check all connections to the gas valve, pilot assembly, burner and regulator.

Regulator: Installer can crack the regulator by over torqueing the connection

Plaque Heaters: Chips or cracks – No replacement (Under Warranty – return unit)

Gas Valve: Leaking around knob – Replace valve

Burner: No replacement (Under Warranty – return unit)

What does the term “sooting” mean?

“Soot” is a fine black to brown powder formed through incomplete combustion. For an object to soot, it must be burned at a low temperature with a reduced supply of oxygen. The use of any chemicals in the air may cause a film to develop on windows, walls and ceilings from the combustion process.

Example: Hold a heat-safe glass over a lit candle, a streak of black will appear from the point of contact.

The main causes for products to cause sooting are:

  • Appliance not cleaned or serviced, at least annually
  • Running a ceiling fan too high or wrong direction
  • Burning scented candles while burning the unit.
  • Low Gas Pressure to the burner.

Where do I find the Model and Serial number?


  • Original Box
  • Owner’s Manual – Top Right
  • Wall Heaters: Hang tags on steel cable or sticker on the side.
  • Gas Logs – Hang tags on steel cable under the grate.
  • Fireplaces – Hang tags on steel cable on back of unit or inside the louver door area.

Serial #: White Sticker approx. ½” x 2½”

  • Original Box
  • Warranty Registration Card
  • Wall Heaters: Hang tags on steel cable or sticker on the side
  • Gas Logs – Hang tags on steel cable under the grate
  • Fireplaces – Hang tags on steel cable on back of unit or inside the louver door area

How do I link the receiver box and remote on my vent-free unit?

Linking remote to receiver:

  • Light pilot & set control knob to “on”.
  • Slide switch on the receiver box “on/off”: the burner should go on and off.
  • Place the receiver slide switch to the “remote” position
  • Press “LEARN” button (right side) to get (1) beep
  • Step Back 3+ Ft. and press “on” on the remote – series of beeps (receiver and remote linked)

Setting Temperature:

  • Press “mode” (“Room” displayed)
  • Press “set” for temperature

What do I if the burner does not light using the remote?

If a “click” is heard and the burners do not light, check the batteries and re-link the remote and receiver. If the burner still will not light, test the solenoid as follows:

NOTE: Removal of the panel in front of the solenoid maybe necessary to access the wires and solenoid

Solenoid “torqued” too tight:

  • With a flat-head screwdriver, turn the solenoid counter-clockwise to loosen
  • Turn solenoid clockwise until thumb-tight.
  • Re-connect the wires.

9-Volt Battery Test:

  • Pilot lit, control knob in the “on” position.
  • Disconnect the receiver from the solenoid (do not remove from gas valve)
  • Place red wire to negative (-) side of battery / black wire to positive (+):

Burner lights, switch the wires on battery to turn “off” – replace receiver box