86 | 180R9288_AQ109686503100en-001301
© Danfoss | 2023.12
Operation guide
Installation, Operation and Maintenance Manual for PAHT 20-90 pumps
Trouble shooting
Closed water systems
The system
does not work
.
Is there sufficient water
in the tank?
No
Yes
No
No
No
Yes
Yes
Yes
Yes
.
Is the water in the tank
very hot? Ie above 50
o
.
Is the power supply ok?
.
Are control lights on?
.
Is the filter clogged?
.
Is the filter control
light on?
.
Replace filter element
Contact serviceman
Stamp
.
Fill water into the system
.
Trace leakage, if any
.
A blown fuse/or short
circuit?
.
Check power supply
and fuses and contact
electrician
.
At temperatures
higher than 50
o
the
pump drive cuts out.
Consequently the
cooler must be
checked/cleaned
.
Is the electric motor of
the pump unit rotating?
No
