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SEAL IT RIGHT THE FIRST TIME

• To seal inner pipe of direct vent
• To seal firebox
• To seal pellet stove - venting and blower (ease of inspection and cleaning)

PREVENTATIVE MEASURES

• Maintain appliance efficiency rating
• Prevent burner instability - reduce sooting
• Prevent corrosion of the burner, pilot and firebox
• Mill-Pac Black does not contribute to whiting on ceramic glass

FIT FOR PURPOSE SEALANT

The root formulation of Mill-Pac has been used in Steel-making to seal the continuous caster moulds, damming molten steel and preventing breakouts. Mill-Pac Black was formulated using this original recipe, with slight changes made through Research and Development and extensive testing by a major Hearth Products Manufacturer. Mill-Pac Black is approved as the "Fit for Purpose" sealant, meeting high production standards and suitability requirements for use in direct vent assemblies.

Natural Gas & Propane form acidic by-products as a result of combustion. These acids will accumulate in the inner pipe exhaust; slowly breaking down silicone sealants that are most commonly applied in the field. Mill-Pac Black will resist the effects of the acidic accumulation, providing an integral seal that will thermal cycle within the fastened joint for the intended lifespan of the appliance.

Acidic by-product components of Flue gas condensate are per ULC-S636-95:

• HCl - Hydrochloric Acid
• H2SO4 - Sulfuric Acid
• HNO3 - Nitric Acid
• NaNO2 - Sodium Nitrate
• HF - Hydroflouric Acid

Mill-Pac Black is comprised of high temperature elemental fibres and ceramic fillers that are encapsulated in a high temperature organic based resin. Mill-Pac Black cures with heat; as heat is applied the sealant will begin to expand and flow into the fastened joint providing a homogeneous high temperature gasket.

USES

Mill-Pac Black has many uses within the Hearth Products Industry:

• Firebox enclosure sealant used during production.
• Sealing the inner pipe of the direct vent assembly from appliance to exterior.
• Sealant suited for pellet vent, as it allows for disassembly for cleaning.

(Note: Mill-Pac Black is not an adhesive. Metal joints must be fastened ensuring the gasket is held in place).

DIRECT VENT / BALANCED FLUE

Direct vent appliances present a different service challenge than other gas appliances. They are designed to operate independently of the positive / negative air pressure of the dwelling they are installed in. This decoupling from the air within the dwelling will prevent any flue gas reversals from forcing the by-products of the combusted natural gas and / or propane to leak into the dwelling place.

The design principle of the direct vent appliance is to draw clean outside air through the outer pipe-(negative pressure), blend it with natural gas or propane to support combustion, and vent all the spent gas by-products outside the dwelling through the inner pipe-(positive pressure).

It is very important to completely seal the inner pipe to energize this direct vent principle, and to maintain efficiency of the appliance to the unit manufacturer's specifications and the approved standards rating of the unit.

TROUBLE-SHOOTING

This high temperature sealant was designed specifically for the Hearth Products Industry to provide the following benefits: good chemical resistance, thermal compatibility, a form in place gasket that expands as it cures, and to prevent appliance service call-backs.

The following symptoms may occur when mortars or silicone are used as the inner pipe sealant: chemical breakdown and cracking that allows combustion by-products to be drawn into the clean air flow of the venting system and accumulate in the firebox.

1. A reduction in appliance efficiency BTU.
2. Burner instability - a change in flames due to contaminated combustion air.
3. Excess carbon buildup (SOOTING) due to incomplete combustion.
4. Increased concentration of the acidic by-products of combustion.

CUMULATIVE EFFECTS

1. Corrosion of the burner and pilot.
2. Corrosion of the metal components of the firebox.
3. Silica based deposits on top of log set due to corrosive leaching.
4. Increased whiting on glass front panel.