Carrier 38VMH-1P Service Manual page 27

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Fan Control in Heating Mode
Table 28 —Fan Control by Outdoor Temperature (T4) and Compressor Frequency
38VMB036, 048HDS3-1
T4 ≥ 50°F
41°F ≤ T4 < 50°F
Max. speed
33.8°F ≤ T4 < 41°F
T4 < 33.8°F
38VMB060HDS3-1
T4 ≥ 50°F
41°F ≤ T4 < 50°F
Max. speed
33.8°F ≤ T4 < 41°F
T4 < 33.8°F
SEQUENCE:
1. Outdoor fan will come on (W7) for 29 seconds before compressor starts.
2. Once compressor starts, based on outdoor temperature (T4), outdoor fan runs at max. speed for the next 180 seconds.
3. After 180 seconds of compressor start, outdoor fan step level is determined based on frequency, T3 and T4.
The compressor will stop and display 'EA' error code suggesting outdoor fan has stayed in Zone A for more than five minutes.
The system will restart approximately three minutes after pressure equalization.
Outdoor fan will adjust the step level every 20 seconds if Pd is greater than 479 psi.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Frequency < 34
W3
W4
W6
W7
Frequency < 34
W4
W6
W7
W7
Fig. 34 —Fan Control Correction by T3 and High Pressure (Pd)
34 ≤ Frequency < 50
W5
W6
W7
W7
34 ≤ Frequency < 50
W6
W7
W7
W7
27
Frequency ≥ 50
W6
W7
W7
W7
Frequency ≥ 50
W6
W7
W7
W7
A210268