Startup; Shaft Seal Run-In - Grundfos CRT Serie Montage- Und Betriebsanleitung

8. Startup

Do not start the pump until it has been filled with
liquid and vented. If the pump runs dry, the pump
Caution
bearings and the shaft seal may be damaged.
Warning
Pay attention to the direction of the vent hole and
take care to ensure that the escaping water does not
cause injury to persons or damage to the motor or
other components.
In hot-water installations, pay special attention to the
risk of injury caused by scalding hot water.
Step
1
2
3
4
5
6
Action
Close the isolating valve on the
discharge side of the pump and
open the isolating valve on the
suction side.
Remove the priming plug from
the pump head and slowly fill
the pump with liquid.
Fit and tighten the priming plug.
See the correct direction of
rotation of the pump on the
motor fan cover.
Start the pump and check the
direction of rotation.
Vent the pump by means of the
vent valve in the pump head.
At the same time, open the
discharge isolating valve a little.
Continue to vent the pump.
At the same time, open the
discharge isolating valve a little
more.
Step
7
CRT 2 and 4
For these pumps, we advise you to open the bypass valve during
startup. See fig. 19. The bypass valve connects the suction and
discharge sides of the pump, thus making the filling procedure
easier. Close the bypass valve again when the operation is
stable.
When pumping liquids containing air, we advise you to leave the
bypass valve open if the operating pressure is lower than 6 bar.
Close the bypass valve if the operating pressure constantly
exceeds 6 bar. Otherwise the material at the opening will be worn
because of the high liquid velocity.

8.1 Shaft seal run-in

The seal faces are lubricated by the pumped liquid, meaning that
there may be a certain amount of leakage from the shaft seal.
When the pump is started up for the first time, or when a new
shaft seal is installed, a certain run-in period is required before
the leakage is reduced to an 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.
Action
Close the vent valve when a
steady stream of liquid runs out
of it. Completely open the
discharge isolating valve.
11