32 - EN
EN - 33
Error code
PREHEAT. ERROR
The preheater does not heat sufficiently.
■
For the right-hand unit: PREHEATER and T21 are to the left;
■
For the left-hand unit: PREHEATER and T21 are to the right.
Question
Answer
Action
1
n/a
n/a
1. Remove the electronics cap as described in the section “Access to the control PCB”.
2. Place a resistance meter over the connector of the preheater (temperature sensor T21).
3. Go to the next question.
2
Is the resistance of
temperature sensor T21
correct?
(See Section “Technical
specifications”)
Yes
1. Disconnect the preheater plug from the control PCB.
2. Place a resistance meter over the connector of the preheater (blue-brown and blue-black).
3. Go to the next question.
No
1. Get the service set for temperature sensor T21.
2. Replace temperature sensor T21 as described in the manual supplied.
3
Does the preheater give an
infinite resistance?
Yes
1. Get the service set for the preheater.
2. Replace the preheater as described in the manual supplied.
3. Follow the procedure for completing the maintenance.
No
Go to the next question.
4
Is the resistance less than
10 Ohm?
Yes
1. Get the service set for the preheater.
2. Replace the preheater as described in the manual supplied.
3. Get the service set for the control PCB.
4. Replace the control PCB as described in the manual supplied.
5. Follow the procedure for completing the maintenance.
No
1. Get the service set for the control PCB.
2. Replace the control PCB as described in the manual supplied.
3. Follow the procedure for completing the maintenance.
Error code
PREHEAT. TOO HOT
The preheater is getting too hot.
■
For the right-hand unit: PREHEATER is to the left;
■
For the left-hand unit: PREHEATER is to the right.
Question
Answer
Action
1
Is temperature sensor T21
replaced with a sensor
that is not supplied by the
manufacturer?
Yes
1. Get the service set for temperature sensor T21.
2. Replace temperature sensor T21 as described in the manual supplied.
3. Follow the procedure for completing the maintenance.
No
1. Inspect the heat exchanger as described in the section “Maintenance of the heat exchanger”.
2. Get the service set for the control PCB.
3. Replace the control PCB as described in the manual supplied.
4. Follow the procedure for completing the maintenance.
2
Does the error alert return
once the preheater is
operated?
Yes
1. Inspect the heat exchanger as described in the section “Maintenance of the heat exchanger”.
2. Get the service set for the control PCB.
3. Replace the control PCB as described in the manual supplied.
4. Follow the procedure for completing the maintenance.
10001047667-0619-zw-zw-A4 ComfoAir E 350 GEN2 Service Zehnder-SI_EN.indd 33
11-07-19 13:31
