Mr. Heater compact unit heaters require careful installation, particularly concerning venting procedures, to ensure safe and efficient operation. This article details venting specifications and installation instructions based on available documentation for Mr. Heater compact unit heaters, focusing on both vertical and horizontal venting configurations. The information presented is intended for U.S. consumers, DIY enthusiasts, and IT professionals involved in the installation or maintenance of these heating appliances.
Venting Requirements and Connector Specifications
The documentation specifies different vent connector diameters depending on the unit model. For 45-unit heaters, the vent connector diameter is 3 inches (76mm). For 50-unit heaters, the vent connector diameter is also 3 inches (76mm). In all cases, a flue transition piece, supplied with the heater kit, is required to connect the vent to the induced draft assembly.
When routing the vent through an exterior combustible wall, support is necessary using a listed clearance thimble. Alternatively, a single section of type B-1 vent pipe may be used as a substitute for the thimble, provided local authorities permit its use. The documentation emphasizes adherence to the American National Fuel Gas Code ANSI Z223.1 or the Canadian CSA B149.1 Natural Gas and Propane Installation Code for maximum vent and vent connector lengths.
Vertical Venting Procedures
Mr. Heater compact unit heaters are listed as Category I appliances suitable for vertical vent installations. When using metal vent pipe for vertical venting, it must conform to NFPA standards. The vent connector should be kept as short as possible with a minimal number of elbows to maximize efficiency.
A type B-1 vent or masonry chimney liner must terminate above the roof surface with a listed cap or roof assembly, adhering to the terms of their respective listings. Testing for spillage is crucial after five minutes of main burner operation, using a flame (match or candle) or smoke (cigarette, cigar, or pipe) to detect backdrafting at the draft hood relief opening.
Horizontal Venting Considerations
Horizontal venting requires specific attention to detail. Due to changes in Unit/Utility Heater compliance with UL 1738 & ULS636, common venting is not permitted when horizontally venting the unit heater. The minimum horizontal vent length is three feet (914mm).
Several factors influence the suitability of a horizontal vent termination point. The documentation advises avoiding termination through a wall exposed to prevailing winds, as this can affect unit performance. The vent termination must be free from obstructions and positioned at least 12 inches (306mm) above grade level and maximum snow height. It should not be located directly below roof eaves, above walkways, or in areas where condensate dripping could cause staining or ice buildup. Avoiding windows is also recommended to prevent steam-related fogging or ice formation.
Minimum clearance requirements for horizontal vent termination are 4 feet (1.2m) from any door, window, gravity air inlet, gas or electric meter, regulators, and relief equipment, specifically for U.S. installations. Referencing NFPA 54/ANSI Z223.1 in the U.S.A. and CSA B149.1 Natural Gas and Propane Installation Code is essential for compliance.
Vent Material and Insulation
For commercial installations, condensate drains can be implemented through a tee pipe and drain loop with an upward slope. Horizontal vents in commercial settings may be sealed using 26 GSG galvanized or equivalent stainless steel, maintaining a minimum slope of +1/4 inch per foot of run, with a minimum length of 12 inches.
When the length of a single wall vent, including elbows, exceeds 5 feet (1.5m), the vent must be insulated along its entire length with a minimum of 1/2 inch thick foil-faced fiberglass insulation. This insulation is crucial for maintaining vent temperature and preventing condensation.
Clearance to Combustible Materials
Clearance to combustible materials is 6 inches (152mm) for single wall vent material, except when a listed clearance thimble is used. The documentation does not specify clearance requirements for type B-1 vent material.
Component Identification
The documentation lists several components available for purchase, including a 4-inch gas vent cap (Ref # 06430), a 4-inch storm collar (02917), an adjustable 4-inch roof protector (02918), an adjustable 4-inch wall protector (02912), a 4-inch 90-degree elbow (02914), and a 4-inch x 24-inch discharge/relief tube (02913).
Safety Warnings and General Precautions
The documentation includes several safety warnings. Failure to follow instructions precisely may result in an explosion or fire, causing property damage, personal injury, or death. It is crucial to keep combustible materials, such as construction materials, paper, and cardboard, at a safe distance from the heater, as recommended in the instructions.
The documentation also includes warnings in Spanish and French, reiterating the importance of following instructions to prevent fire, burns, inhalation hazards, and explosions. It emphasizes the need for qualified service personnel to perform installations and provides contact information for obtaining service or parts.
Warranty Information
The provided warranty information states that the warranty gives specific legal rights, and other rights may vary from state to state. Mr. Heater, Inc. reserves the right to make changes at any time, without notice or obligation, in colors, specifications, accessories, materials, and models.
Conclusion
Proper venting is paramount for the safe and efficient operation of Mr. Heater compact unit heaters. The documentation details specific requirements for vent connector diameter, vertical and horizontal venting procedures, material specifications, and clearance to combustible materials. Adherence to these guidelines, along with relevant national and local codes (ANSI Z223.1, CSA B149.1, NFPA 54), is essential for ensuring a safe and reliable heating system. The documentation stresses the importance of professional installation and regular maintenance to maximize performance and longevity.