Resolving Residential Low Water Pressure
Resolving residential low water pressure is as easy as installing the following:
1. 1 Shallow-Well Jet Pump.
2. 1 Check Valve.
3. 1 Pressure Switch with low water cut-off.
4. 1 Relief Valve
5. 1 Bladder Tank
6. 2 Unions
7. 2 Gate Valves
Begin by determining how many gallons per minute are available to the pump at point of entry. This may be accomplished using (2) five-gallon buckets and a stopwatch, or watch with a sweep hand. Open valve at point of entry and run water for 1 minute. This is water available. Check at several points during the day and use the lowest reading. Select pump for GPM available @ 20 PSI mark on performance chart to avoid starving pump suction. Install check valve downstream of pump and before bladder tank to prevent blowback from tank. Shallow well Jet pumps come equipped with standard pressure switches usually designed to come on at 30 PSI and shut-off at 50 PSI. Provision should be made to protect the pump in the event of low-water / no-water situation as would occur should a water main break, hydrant flushing, or general water main maintenance. A pressure switch with a low water cut-off should be specified. Bladder Tank selection should be made based on several factors. The amount of drawdown (water in gallons) used before pump senses a drop in pressure and replenishes, GPM available, and desired water pressure to residence. A general rule of thumb is the larger the bladder tank, the less often the pump runs. Water pressure to the residence is adjusted by air pressure in the bladder tank. Most bladder tanks are factory pre-charged at 28 PSI so pumps will activate at 30 PSI, and shut off at 50 PSI. This is by no means cut-in-stone, and may be adjusted to suit personal preference. Always use good judgement and consider age of pipe, amount of corrosion build up, and fixture limitations when determining water pressure settings. In most cases factory settings are adequate. Install unions and gate valves before pump and after bladder tank to facilitate maintenance requirements and future pressure adjustments. Sequence of events is as follows: Install gate valve, union, pump, check valve, relief valve, bladder tank, union, and gate valve to system. Open valves on both sides of system. Upon activating power supply to pump, pressure switch senses a drop in pressure, and starts pump. When tank is filled, pressure switch senses an increase in pressure and automatically shuts off pump. System is now operational and fully automatic. Open faucets to purge air and check aerators for sediment. To adjust water pressure, shut off power to system and open faucets to drain tank. To increase water pressure, increase air pressure to bladder tank. Note: Bladder tank pressure should always be 2 PSI less than pressure switch set pressure.
1. Is the residence vacant occasionally? If so, select a Jet Pump constructed of Plastic or Stainless Steel, in lieu of Cast Iron, to avoid barnacle growth inside pump, which may impede pump impeller rotation, and cause premature mechanical seal failure.
2. Will motor be wired @ 115 or 230 Volt Service. If wired for 230 Volt and residence is further off power grid, a buck-booster may be required.
3. Will Booster be located in a clean, dry environment or will moisture/ dust be present? Select ODP (Open Drip Proof) motor, or TEFC (Totally Enclosed Fan Cooled) Enclosure as required.
4. Bladder Tank Selection. Select a Bladder Tank large enough so as not to short-cycle pump. This will be determined by the GPM (Gallons per Minute) available to the system. A 40-119 Gallon Tank is usually acceptable.