1. Technical Support Step-By-Step
Created on 09/19/05
How to Simulate Water Detection with the 5821
A metal short is not the same as a water short. To simulate a water short, a 10K
resistor can be placed across the water probe circuit with the 2.2M ohm resistor
in parallel producing close to a 10K resistance. The 10K resistance has to be in
place for approximately 3 minutes before the transmitter sends the fault. Before
the transmitter will send a restore on the zone, it has to see the 2.2M ohm
resistance, again, for approximately 3 minutes.
This configuration can also provide a way to integrate a hard wired water probe if
the probe circuit has to be longer than 48 inches. The hard wired probe would
have to close its own relay per a water trip. This relay would have to be wired in
series with the two 5K resistors (both in series to be 10K). The relay and both
resistors would then be in parallel with the 2.2M resistor. When the relay closes,
the 5821 would see the 10K and 2.2M resistors in parallel, thus having approx
10K to trip the 5821. The two 5K resistors would help prevent any Electro-
Magnetic Interference (EMI) that could occur, as long as they are near the 2.2M
resistor.
5821
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
2.2M ohm 
48” 


5K ohm 5K ohm
Hard wire water sensor
with N.O. relay