134
Message
System characteristics Cause
Measures
«
20 Flow sens. secondary
Operation with tempera-
ture value of return tem-
perature sensor in sec-
ondary circuit, plus 5 K. If
both temperature sen-
sors (secondary flow and
return) are faulty, the
heat pump stops (mes-
sage
U
A9).
Short circuit, secondary
circuit flow temperature
sensor
Check resistance (Pt 500)
at connections 3X1.20
and 3X2.20; replace sen-
sor if required.
«
21 Sec. return sensor
Operation with tempera-
ture value of flow temper-
ature sensor in secon-
dary circuit, minus 5 K. If
both temperature sen-
sors (secondary flow and
return) are faulty, the
heat pump stops (mes-
sage
U
A9).
Short circuit, secondary
circuit return temperature
sensor
Check resistance (Pt 500)
at connections 3X1.19
and 3X2.19; replace sen-
sor if required.
«
28 Flow sens. secondary
Operation with tempera-
ture value of return tem-
perature sensor in sec-
ondary circuit, plus 5 K. If
both temperature sen-
sors (secondary flow and
return) are faulty, the
heat pump stops (mes-
sage
U
A9).
Lead break, secondary
circuit flow temperature
sensor
Check resistance (Pt 500)
at connections 3X1.20
and 3X2.20; replace sen-
sor if required.
«
29 Sec. return sensor
Operation with tempera-
ture value of flow temper-
ature sensor in secon-
dary circuit, minus 5 K. If
both temperature sen-
sors (secondary flow and
return) are faulty, the
heat pump stops (mes-
sage
U
A9).
Break, secondary circuit
return temperature sen-
sor
Check resistance (Pt 500)
at connections 3X1.19
and 3X2.19; replace sen-
sor if required.
Troubleshooting
Control unit diagnostics
(cont.)
5414 828 GB
Summary of Contents for VITOCAL 350-A
Page 54: ...54 5 3x 7 6 3x 3x 3x Installation sequence Fitting the outer panels cont 5414 828 GB ...
Page 58: ...58 2x 10 11 3x 3x Installation sequence Fitting the outer panels cont 5414 828 GB ...
Page 62: ...62 Type AWH I 1 Installation sequence Installing the heat pump cont 5414 828 GB ...
Page 228: ...228 052 054 059 008 056 025 020 Parts lists Parts list type AWH I cont 5414 828 GB ...
Page 236: ...236 053 032 039 034 038 033 034 039 027 Parts lists Parts list type AWH O cont 5414 828 GB ...
Page 237: ...237 052 054 059 008 055 025 020 Parts lists Parts list type AWH O cont 5414 828 GB Service ...