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Saves You Energy, LLC
Water Conservation Technologies
On-Demand Bypass Flow Sensor
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The On-Demand Bypass Flow Sensor
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The heart of the On-Demand Intelligent Pump system is the remote sensing capability. The flow
and temperature sensors allow the pumping system to respond in real-time to actual events
(demand for hot water) in an intelligent energy conservation manner.
The purpose of the By-pass Loop is to sense the smallest flow in the cold-water make-up line.
If any hot water is used in a building it is made up with utility provided water through the
cold water make-up line.
For example, if a hotel guest turns on a hot water faucet, a small amount of hot water leaves
the system. Water from the utility water main is pushed in to the building system by the
street water pressure.
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Typical water meters are designed to measure the amount of water used in relatively large
quantities of water - i.e., one gallon increments. Standard electronically read water
meters transmit a pulse every one gallon. If a faucet aerator allows 2 gpm, only 2 pulses
would be sent every minute.
We can not wait that long to tell the pump that there is a demand for water. In order to
monitor extremely small amounts of water usage, we developed a low-flow sensor that transmits
up to 1,200 pulses per gallon of water. So even the smallest amount of water usage will let
the pump know there is a demand.
In order to be as sensitive to low flow as possible the flow sensor was designed with a
maximum flow rate of between 5 and 8 gpm, depending on the water pressure. The flow rate
is well below what is required to provide enough water to a single apartment let alone 40 or 50 units.
Hence, the need for a By-Pass Flow Sensor. If a small portion of the overall flow is
diverted through the flow sensor, small amounts of flow could be sensed and full capacity
can still be provided when necessary.
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The Bypass Loop - How It Works:
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Letters in ( ) refer to the By-Pass Flow Sensor Diagram.
A spring loaded check valve (a valve that does not allow water to flow backwards in a system)
is inserted in the cold water make-up line (E).
Tees - (A), (B) and (C) - are installed on both the upstream and downstream side of the check
valve. (C) is the by-pass leg of the tee and is always ½".
(A), (B) and (D) are always the size of the cold water make-up line - i.e., (A), (B) and (D)
are 1" for a 1" cold water make-up line.
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Shut-off valves are installed on each tee so that the Flow Sensors can be isolated if maintenance is required.
The Flow Sensor is installed on the downstream side of the BY-Pass Loop. (2) - 22 gauge
wires (low voltage thermostat wire) are connected to the Flow Sensor and ran over to the pump.
These wires can be up to 300' long but are typically less than 10' in length. As water flows
through the pipes, backpressure forms and the spring loaded check valve will divert a small
amount of flow through the By-Pass Loop. As little as a couple of drops of water can be sensed
by the Flow Sensor, which then sends a signal to the On-Demand Control Panel.
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On-Demand Intelligent Pump Components
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Send us an
email or give us a call at 702 567 1791
for further information.
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