Therma-Stor Products Group TS-261B owner manual Negative Air Ducting, Power/Speed Control

2.5 Air Ducting

2.5A Inlet Ducting

Occasionally the area to be filtered is difficult to access and/or the unit cannot be located in the area. In such cases, the air can be ducted to the unit’s inlet.

A round 12” diameter flexible duct can be attached to the unit inlet on top. It connects by placing the wire in the duct under the four tabs on the top. It may be removed after use for easier transport and storage. Flexible 12” duct is available from Therma-Stor LLC.

Figure 5: Inlet ducting

2.5B Outlet Ducting

A detachable rectangular exhaust collar is supplied that will allow 10” round lay-flat plastic duct to be attached to the Phoenix Mini-Guardian HEPA System outlet. Lay-flat plastic ducting is available from Therma-Stor LLC.

To attach ducting to a collar, remove the collar from the unit by sliding the collar upward out of the guide. Put the plastic duct end through the collar center. Roll the duct end outward so that it over-laps the outside of the collar. The duct will hook over the collar, preventing it from slipping off.

Figure 6: Outlet ducting

2.6 Negative Air Ducting

The Phoenix Mini-Guardian HEPA System can be used to filter and exhaust air from a space. By exhausting to outside the space, the space will be under a slight negative pressure. This will help prevent airborne particles from leaving the space, since the negative pressure will draw air in through openings in the space’s exterior.

The quantity of air exhausted depends on how the unit is ducted and what speed is used. A duct can be directed outside. Cover the other exhaust openings to direct all the filtered air outside. This would result in up to 400 CFM being exhausted on high speed and an equal amount of fresh air being drawn in.

CAUTION: Exhausting too much air from a space with open combustion devices (e.g. furnace, fireplace or water heater) can cause those devices to backdraft. This can contaminate the space with potentially fatal gases.

In such cases, the Phoenix Mini-Guardian HEPA System must be used in one of the following three ways:

A.As a filtering unit only. Exhausting no air from the space and thus causing no negative pressure or backdrafting.

B.Exhausting a very limited amount of air which does not cause backdrafting. In case B, the open combustion devices must be thoroughly checked to guarantee that they do not backdraft while the Phoenix Mini-Guardian HEPA System is running.

C.Direct the outlet duct from the Mini-Guardian HEPA System to the room with the open combustion device(s). This will positively pressurize the room, thus preventing backdrafting. As in case B, those combustion devices must be checked after the Mini- Guardian HEPA System is running to guarantee that they are not backdrafting.

The duct can be directed outside, exhausting a portion of the filtered air. The rest of the filtered air is recirculated inside the space. Blocking the other supply holes will determine the amount of air that is exhausted. By adjusting the blocking plates over the supply openings, the quantity exhausted can be adjusted down to no flow.

2.7 Power/Speed Control

The power/speed switch is located in the recessed cavity on the unit front. When turned on to any speed, it powers the impeller fan and hour meter.

Occasionally the impeller fan may not start on low speed. If this occurs, rotate the speed control to high speed until the impeller fan starts, then adjust it to a lower speed.

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