Mr. Heater MHU 50, MHU 80 Venting Using a Masonry Chimney, Removal of Unit from Common Vent

INDUCED DRAFT BLOWER	HORIZONTAL VENTING - RESIDENTIAL INSTALLATION
	UPWARD SLOPE
	12 INCHES
	MIN. (30.5CM)
	FLUE TRANSITION
	(PROVIDED)

VENT TERMINATION CAP

LISTED THIMBLE THROUGH

COMBUSTION WALL

CATEGORY III VENT ACCORDING TO THESE INSTALLATION

INSTRUCTIONS.

SLOPED: + 1/4 INCH FOR 1 FOOT RUN MINIMUM.

NOTE - MINIMUM HORIZONTAL LENGTH 3FT. (914MM), NOT INCLUDING CAP FOR TERMINATION.

MAXIMUM HORIZONTAL LENGTH 5FT. (1.5M) PLUS ONE

90-DEGREE ELBOW.

COMMON VENTING NOT ALLOWED WHEN HORIZONTALLY VENTING THE UNIT / UTILITY HEATER.

FIGURE 6

F – VENTING USING A MASONRY CHIMNEY

The following additional requirements apply when a lined masonry chimney is being used to vent the compact unit / utility heater.

1.Masonry chimneys used to vent Category I units heaters must be either tile-lined or lined with a listed metal lining system or dedicated gas vent. Unlined masonry chimneys are prohibited. A category I appliance must never be connected to a chimney that is servicing a solid fuel appliance. If a fireplace chimney flue is used to vent this appliance, the fireplace opening must be permanently sealed.

2.A fan assisted unit heater may be commonly vented into an existing lined masonry chimney provided:

•The chimney is currently serving at least one draft-hood equipped appliance.

•The vent connector and chimney are sized in accordance with venting tables in the (American) National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1 Natural Gas and Propane Installation Code.

IMPORTANT Single appliance venting of a fan assisted unit heater into a tile lined masonry chimney (interior or outside wall) is prohibited. The chimney must first be lined with either type B-1 vent or an insulated single wall flexible vent lining system, sized in accordance with venting tables in the (American) National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1 Natural Gas and Propane Installation Code.

3.A type B-1 vent or masonry chimney liner shall terminate above the roof surface with a listed cap or a listed roof assembly in accordance with the terms of their respective listings and the vent manufacturer’s instructions.

4.Do not install a manual damper, barometric draft regulator, or flue restrictor between the unit heater and the chimney.

5.If type B-1 double-wall vent is used inside a chimney, no other appliance can be vented into the chimney. Outer wall of type B-1 vent pipe must not be exposed to flue products.

6.Insulation for the flexible vent pipe must be an encapsulated fiberglass sleeve recommended by the flexible vent pipe manufacturer.

7.The space between liner and chimney wall should NOT be insulated with puffed mica or any other loose granular insulating material.

8.If type B-1 vent or an insulated flexible vent pipe cannot be used as liners, the chimney must be rebuilt to accommodate one of these methods or some alternate approved method must be found to vent the appliance. When inspection reveals that an existing chimney is not safe for the intended purpose, it shall be rebuilt to conform to nationally recognized standards, lined or relined with suitable materials or replaced with a gas vent or chimney suitable for venting unit heaters. The chimney passageway must be checked periodically to ensure that it is clear and free of obstructions.

G – REMOVAL OF UNIT FROM COMMON VENT

In the event that an existing unit heater is removed from a venting system commonly run with separate gas appliances, the venting system is likely to be too large to properly vent the remaining attached appliances. The following test should be conducted while each appliance is in operation and the other appliances are not in operation, yet remain connected to the common venting system. If the venting system has been installed improperly, the system must be corrected.

1.Seal any unused openings in the common venting system.

2.Visually inspect the venting system for proper size and horizontal pitch. Determine there is no blockage or restriction, leakage, corrosion, or other deficiencies which could cause an unsafe condition.

3.If practical close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliances not connected to the common venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan. Close fireplace dampers.

4.Follow the lighting instructions. Place the appliance being inspected in operation. Adjust thermostat so appliance will operate continuously.

Compact Unit / Utility Heater E-8 Operating Instructions and Owner’s Manual