Retrotec DM-2A Instrukcja Użytkownika Pobierz pdf (Strona 51)

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7.8 No reference tube while pressurizing

Model 1000, 2000, and 3000 fans are automatically referenced by the gauge, and do not require

reference tubing (the green tube) for accurate results. Whenever the DM-2 measures a positive

pressure, and knows that the fan flow is towards a greater pressure, it makes the necessary deductions

from the Fan Pressure.

Model 3000SR fans are self-referenced, and include a connection point for the green tube, which must

be connected.

7.9 Windy conditions

High fluctuations of bias (baseline) pressures on the gauge (greater than 2 Pa) are a good indication

that wind may be a large source of error. In windy conditions, the house/room gauge will fluctuate. If

the fluctuation is greater than 2 Pa due to wind buffeting, a wind damping system can be used to

average out the wind, and get a more stable pressure reading. In addition to a number of suggestions

for obtaining better performance from a single tube system (see 7.4), Retrotec offers two wind-

damping kits specifically designed to reduce the pressure fluctuations due to wind.

The basic wind-damping kit consists of a dual-tube pressure averaging system and will work in wind

conditions up to about 10 mph. The deluxe wind-damping kit (our “Wild Wind Tamer”) consists of a

four-tube engineered damping system that will provide damping results in winds up to 20 mph.

Using a wind-damping kit

1. Set up the house/room gauge and red tube as normal.

2. Connect the open end to the T-connection on the basic wind-damping kit; connect the open

tube to the output port on the deluxe wind-damping kit.

3. Place the wind-damping tubes away from the building to avoid the pressure pulse that gets

created when the wind hits the wall.

4. Cover the end of the tubes with sheet material/a box to stop the wind, if required.

Figure 14. Wind-damping kits; basic (left) and deluxe (right).

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Retrotec DM-2A Instrukcja Użytkownika Strona 51