Sampling - QED MP50 Instruction Manual

Operation
The MP50 and MP30 are connected with a cable (see Figures 5 and 6). The MP30 is switched
into mode and the water level probe is lowered to the desired maximum drawdown level.
Limiting the maximum drawdown depth limits the differential head driving flow into the well and
the velocity of the water flowing into the well from the surrounding formation important in Micro-
Purge sampling. The MP50 and MP30 work together to automatically adjust the pump opera-
tion so as to maintain drawdown at the set level. When the water level drops below the probe,
the MP30 sends a signal to the MP50 to pause pumping. Both the MP50 and the MP30 give
visual signals (and the MP30 emits an audio signal) that pump operation has stopped because
of too much drawdown. Once the level recovers, the MP30 signals the MP50 to resume pump
operation. The MP50 resumes by starting in the refill leg of the pump cycle. "DRAWDOWN
CONTROL"
The normal operating mode for using the MP30 with the MP50 is:
1. Use the MP30 in standard WLM mode to determine the static water level in the well
2. Decide what the maximum drawdown for that well is during sampling
3. Lower the probe to the maximum drawdown level
4. Switch the MP30 into Drawdown Control mode
5. Begin pumping with the MP50
6. Observe the interactions between the two devices, if the MP30 is frequently pausing the
MP50, it may be appropriate to slow the flow down (using the DOWN key in MP mode) to
better match pump flow to well recharge.
When switched into mode, the MP30 has a flashing red light and an optional (can be switched
off by the user) audio alarm to indicate when the probe is in the dry state. A submerged probe
in all modes is indicated by a solid green light. When the MP50 is paused by the MP30 the MP
50 display indicates this as shown in Figure 4 "DRAWDOWN CONTROL"
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