FlowForge
Pressostat de pompe de puits : guide OEM et gros
Un pressostat démarre la pompe de puits quand la pression descend au seuil d'enclenchement et l'arrête au seuil de déclenchement, avec un réservoir sous pression. Cette page OEM et gros explique réglages, réservoir, types, calibres et pannes courantes, et la fourniture des commandes avec les groupes ou kits. Page d'approvisionnement, pas une boutique.
What a well pump pressure switch does
Cut-in, cut-out and the differential
The switch watches water pressure in the system. When a tap opens and pressure falls to the cut-in setting, the contacts close and the pump starts. When pressure climbs to the cut-out setting, the contacts open and the pump stops. The gap between the two is the differential; a wider gap means fewer starts but a bigger swing in pressure at the tap.
It works as a pair with the pressure tank
The pressure tank stores a volume of water under an air cushion, so the pump does not start for every glass of water. As a general rule, the tank air pre-charge is set a little below the cut-in pressure (often about 2 psi below), checked with the tank empty of water and the power off. A correct pre-charge and a suitably sized tank give longer run times and fewer starts.
Setting ranges, adjustment and switch types
Common setting ranges
Mechanical well switches are commonly sold in ranges such as 20/40, 30/50 and 40/60 psi (cut-in/cut-out). These are general market conventions, not specifications of FlowForge products. The right range depends on the fixtures, the building height and what the pump can deliver at the cut-out point on its curve.
Adjustment basics
On a typical mechanical switch, a main spring nut moves cut-in and cut-out together, and a smaller differential nut moves mainly the cut-out. Adjust in small steps, keep the cut-out within the pump curve and the tank and piping ratings, and re-check the tank pre-charge after changing cut-in.
Low-pressure cut-off versions
Some switches add a lever or trip that shuts the pump off and holds it off if pressure falls well below cut-in, for example when the well runs dry or a pipe breaks. It needs a manual reset. It is a useful extra guard, not a replacement for dedicated dry-run protection.
Mechanical vs electronic and constant-pressure control
A mechanical diaphragm switch is simple and easy to replace. Electronic pressure controls add dry-run sensing, adjustable settings and displays. Constant-pressure controllers with a variable-speed drive hold a set pressure by changing motor speed and usually work with a smaller tank. Choice depends on the pump, motor type and budget.
Voltage and contact rating
The switch must suit the supply voltage and the motor load it switches. Check the contact rating against the motor full-load current and horsepower at that voltage; larger or three-phase motors switch through a contactor or starter rather than directly. Rating marks and listings must be confirmed on the actual part for the target market.
Connection and sensing port
Switches mount on a tank tee or fitting with a threaded port, commonly 1/4-inch in the North American market. A short, clean sensing line close to the tank reduces chatter. State the thread standard your market uses.
Typical faults and what they usually mean
Short cycling
The pump starts and stops every few seconds. Usual causes: a waterlogged tank or lost air pre-charge, a failed tank bladder, a differential set too narrow, or a leak in the system.
Chattering contacts
Rapid on-off clicking near the set point, often from pressure surges in a long or remote sensing line, a partly blocked port, or a worn switch.
Pitted or burned contacts
Arcing from many starts or an undersized switch roughens the contacts until the pump will not start or will not stop. Replace the switch and fix the cause of the frequent starts.
Clogged pressure port
Sediment, iron or scale in the nipple or tee stops the switch from seeing true pressure. Clean or replace the fitting; on dirty water a filter or separate tee helps.
Waterlogged tank
With no air cushion the tank stores almost no water, so the pump short-cycles. Check pre-charge with the tank drained; a tank that will not hold air usually needs replacing.
Safety first
Isolate and lock off power before removing the switch cover or touching wiring or the adjustment nuts, and relieve water pressure before removing the switch. Use a licensed electrician where local rules require one. This page is general information, not installation instructions.
Pairing the switch with the pump type
Submersible well pumps
A borehole submersible runs from a surface switch and tank, through a control box on 3-wire motors. Settings must sit within the pump curve at the well depth. See the deep well pump page and the submersible water pump hub.
Jet and shallow-well pumps
Jet pumps usually carry the switch on the pump body with a tank nearby. Lost prime shows up as low pressure, so low-pressure cut-off versions are common. See the jet pump guide and shallow well pump page.
Booster pumps
Boosters on mains or tank supply use a pressure switch and tank, a flow switch, or a constant-pressure controller. See the booster pump page.
Choosing the pump first
The switch follows the pump, not the other way round. Start with the well pump guide to choose submersible, jet or booster from the well data.
RFQ checklist for pressure switches and pump controls
Switches and controls are supplied as part of pump sets or kits and quoted from a duty sheet. Send these fields on the inquiry form; the pump spec guide has the general RFQ brief.
Pump type
Submersible, jet, shallow-well or booster; motor power, phase and 2-wire or 3-wire.
Pressure range
Required cut-in/cut-out, or constant-pressure set point; low-pressure cut-off yes or no.
Voltage and load
Supply voltage and frequency, motor full-load current, target market rules.
Connection thread
Port size and thread standard, tank tee or kit fittings, gauge required.
Tank size
Tank volume and pre-charge, or ask us to propose one with the pump set.
Branding and quantity
Private label, packaging, kit contents, lot size and annual quantity.
What the catalog covers
The FlowForge catalog does not list a standalone pressure switch, pressure control or pressure tank SKU, so no switch products are shown on this page. Switches and controls are quoted as part of a pump set or kit to your duty sheet. For pumps, see the transfer line and custom OEM.
Two ways to buy
OEM and private label
Building a well pump and controls range under your own brand? Start from a duty sheet. See Custom OEM for options and the private-label hub for housing, label and packaging.
Wholesale supply
Buying in crate lots for distribution or installation? The wholesale hub covers lots and spares. MOQ is quoted by SKU, not as a site-wide number.
Well pump pressure switch FAQ
Do you sell pressure switches to consumers?
No. This is OEM and wholesale supply for brands, distributors and installers, with no cart and no public price. Send a duty sheet on the inquiry form.
Is there a standalone pressure switch in your catalog?
No. The catalog does not list a standalone switch SKU. Switches and controls are supplied as part of pump sets or kits and quoted to the duty sheet.
What do 30/50 or 40/60 mean?
They are the cut-in and cut-out pressures in psi: the pump starts at the first number and stops at the second. They are common market ranges, quoted here as general knowledge.
How should the tank pre-charge be set?
Generally a little below cut-in, often about 2 psi below, measured with power off and the tank drained of water. Follow the tank maker instructions.
Why does my pump short cycle?
Most often a waterlogged tank or low pre-charge, a narrow differential or a leak. A clogged sensing port can also cause erratic switching.
Mechanical switch or constant-pressure controller?
A mechanical switch is simple and low cost. A constant-pressure controller gives steadier pressure and soft starts but costs more and must match the motor. We quote either with the pump set.
Can you private-label pump and control kits?
Yes. OEM and private-label kits are quoted from a duty sheet. See private label and wholesale.
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