Engineered air EngA W-TRAC, Инструкция по установке, эксплуатации и обслуживанию

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A
W-TRAC
IOM‐49 9 of 12 Mar 99 R4
When the outdoor ambient temperature is below 15°F (‐10°C) the speed of the heat wheel will be reduced
to maintain the leaving exhaust air humidity between 80 – 90%. This application requires high accuracy
humidity sensors.
RETURN AIR RH% SENSOR
This method of frost control requires a RH sensor installed in the equipment return air section, just before
the heat wheel, wired into terminals RMH and C2. DIP 3 must be ON, DIP 1 and 2 must be OFF.
Using the values of the RH and ambient (outside air) sensor, the W‐TRAC calculates the minimum
allowable exhaust air temperature that will keep frost from forming on the wheel.
BDRH PREDICTED RETURN AIR RELATIVE HUMIDITY
RH% sensing is not used in this method of frost control. DIP 1 and 3 must be ON, while DIP 2 is OFF.
The W‐TRAC may operate without the use of humidity sensing in situations where the RH% values are
expected to be reasonably constant. In these cases, the W‐TRAC operates by sensible temperature only.
When enabled, the BDRH pot (Building Design Relative Humidity) is set according to the expected design
return air conditions. Refer to the table below to set the expected values based on temperature and RH%.
Table 1
BDRH setting
Return Air Conditions
70°F (21°C) 75°F (24°C) 80°F (27°C)
1 < 25% < 21% < 18%
2 26 – 32% 22 – 27% 19 – 23%
3 33 – 39% 28 – 33% 24 – 27%
4 40 – 49% 34 – 42% 28 – 35%
To use this table, first select the return air temperature, then select the RH% range in the column below,
then select the BDRH setting to the left.
WIRING
The W‐TRAC terminals H and N require a minimum 24 VAC, 40 VA class 2 power supply that does not need
to be isolated from the rest of the systems components.
Terminal N should be wired to the common of the same source supplying power to terminals E, A, and K.
All remote wiring should be installed in a clean (no electrical noise) environment. Wire size should be a
minimum of 24ga. twisted pair to reduce electrical noise (shielded wire is recommended). For longer runs