Event: Communication error between indoor and outdoor units during tracking.
Outdoor unit display: E201: It could be as simple as an Indoor unit powered off to a break in the communication wires as they are daisy chained in the system. The E-201 will not allow connection with TUT .
- Lot of cases I've seen where the E-201 wasn't easily found, this is a F1/2 Communication loss, not R1/2 or OF1/2. Remove these wires from the Main outdoor unit You will need to get some device/s talking in the system.
- If it's a heat pump system , basically find the first indoor unit in the F1/2 Link and remove all units but the first one , set the Quantity to 1/1 at the outdoor and press the K3 Rest button one time, if it's not the first one that's having issues , Then add another back in and change quantities at the outdoor unit as you add one back to the system .
- if it's a heat recovery unit, find the first MCU (BRANCH BOX) And one Indoor unit, leave this dip switch on for this unit , turn all the others off for port assignments . , set the quantities at the outdoor unit to 1/1 , if that doesn't bring it back, connect to another indoor unit, turn off MCU Port dip switches for the dedicated unit , keep trying to you get something in the system to communicate .
- Compare the actual quantity of installed indoor
units to the number set on the rotary switches
during outdoor unit installation.
2.Is the actual quantity of
installed indoor units and the number set on
the rotary switches during
installation the same. Next Gen will need to be programmed in the unit using the K1/K2 buttons together for 5 sec. Reference page 66 of VRF-SVN34E-EN for instructions.
3.Press button K3 on the outdoor control board
to view the quantity of indoor units that respond
to tracking.
4.Does the display respond by showing
the indoor unit tracking quantity?
5.Remove the communication cable that connects
the outdoor unit to the indoor unit, and measure the
2 cables of the outdoor unit with a scope.
6.Is the voltage between
the 2 cables a square wave with
± 0.7 Vdc or more? This should be checked at the first F1/F2 Connection indoors, remove wires from MCU or Indoor unit if it's s HP to verify, not connected to the terminals.
7.Check the communication cable that connects the outdoor
unit to the indoor unit. If the connection is good, then
connect the indoor units one by one to find the unit that
is interfering with communication. Change the control
board on the indoor unit that is found to be at fault.
8.Essential Requirements Before Control Board Changes in Case of Communication Error
Occurrence
1. Find the communication IC near the communication terminal.
• Indoor unit
• Above red connector: communication IC between indoor and outdoor units.
• Above blue connector: communication IC for cable remote control.
• Outdoor unit
• When there is module communication as in PLUS II and PLUS III.
• Above red connector of main unit: communication IC between indoor and outdoor units.
• When there is no module communication as I PLUS II and PLUS III.
• Above yellow connector of each unit: communication IC between outdoor units.
9.Outdoor Unit
2. Measure the resistance of the communication control board.
• Measure the No. 5 — No. 6 pin resistance
• Measure the No. 5 — No. 7 pin resistance
• Measure the No. 5 — No. 8 pin resistance
10.• Judging as normal
• Each resistance value should be measured in tens of k
- If you power one of the indoor units off to work on it, after the repair when you power back up and you are getting a E-201 at the outdoor unit that won't reset with the K3 Button , keep your TUT during repairs , go to the control icon , and press the Network reset tab , in most cases this will reset the E-201 .
See PowerPoint below for illustrations.