Grundfos TPE2 - 11 Operating Conditions; Maximum Number of Starts and Stops; Alternating Operation of Twin-Head Pumps; Liquid Temperature

acceptable level. The time required for this depends
on the operating conditions, i.e. every time the
operating conditions change, a new run-in period will
be started.
Under normal conditions, the leaking liquid will
evaporate.
As a result, no leakage will be detected.
However, liquids such as kerosene will not evaporate.
The leakage may therefore be seen as a shaft seal
failure.
11. Operating conditions
11.1 Maximum number of starts and stops
The number of starts and stops via the power supply
must not exceed four times per hour.
When switched on via the power supply, the pump will
start after approximately 5 seconds.
If a higher number of starts and stops is desired, use
the input for external start/stop when starting or
stopping the pump.
When started via an external on/off switch, the pump
will start immediately.
11.2 Alternating operation of twin-head
pumps
On twin-head pumps, the duty and backup pumps
must be alternated on a regular basis, i.e. once a
week, to ensure an even distribution of the operating
hours on both pumps. The pumps alternate
automatically. See section "Multipump setup" (Setup
of multi-pump system).
If twin-head pumps are used for pumping domestic
hot water, the duty and backup pumps must be
alternated on a regular basis, i.e. once a day, to avoid
blocking of the backup pump due to deposits such as
calcareous deposits. The pumps alternate
automatically. See section "Multipump setup" (Setup
of multi-pump system).
If twin-head pumps are alternated by an
external controller, it is recommended to
alternate the pumps at least once every 24
hours to avoid seizing shaft seals.
Related information
17.49 Multipump setup (Setup of multi-pump
system)
11.3
Liquid temperature
-25 °C (~ -13 °F) up to +120 °C (~ +248 °F).
The maximum liquid temperature depends on the
shaft seal type and the pump type.
Depending on the cast-iron version and the pump
application, the maximum liquid temperature may be
limited by local regulations and laws.
The maximum liquid temperature is stated on the
pump nameplate.
If the pump is used for liquids at high
temperatures, the life of the shaft seal and
the built-in Grundfos sensor may be
reduced.
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