Cb1, Cb2, Cb3, Cb4: Overmatch Protection - Midea VRF Series Service Manual

V6R VRF 50/60Hz

2.30 CB1, CB2, CB3, CB4: Overmatch protection

Digital display output
Description
 CB1: VRF indoor exceeds the match range (the highest priority)
 CB2: AHU kit exceeds the match range (second highest priority)
 CB3: HT exceeds the match range (third highest priority)
 CB4: The total connection ratio exceeds the match range (the fourth highest priority)
 All units stop running.
 Error code is only displayed on the master unit.
Trigger / recover condition
 Trigger condition: the indoor unit connection ration exceeds the match table below.
 Recover condition: the indoor unit connection ration in the range of the match table.
 Reset method: Manually restart.
Table 6-2.1: Match table
IDU1 IDU2
/
VRF indoor HT
/
AHU kit /
Notes:
1.
X is 205 for single outdoor unit system; X is 155 for 2 outdoor units combination system; X is 135 for 3 outdoor units combination units system
Possible causes
 Connection ratio does not meet the requirements.
Procedure
144
Total
IDU3 connection
ratio A(%)
1
/ 40 ≤ A ≤ X
/ 40 ≤ A ≤ 205
AHU kit 40 ≤ A ≤ X 1
/ 40 ≤ A ≤ 115
CB1, CB2, CB3, CB4
Change indoor unit connection ratio
IDU1 IDU2
connection connection
ratio B(%) ratio C(%)
1
40 ≤ B ≤ X /
40 ≤ B ≤ X 1 C ≤ 105
40 ≤ B ≤ X 1 /
/ /
IDU3
connection Note
ratio D(%)
/
Connect at least
/
one VRF Indoor
C ≤ 65
D ≤ 115