Low/High Pressure Switch – Danfoss Type | UV Water Systems Oman

A pressure switch is a relatively inexpensive component that prevents the most costly failures in an RO water treatment system. In Oman’s water supply infrastructure, two failure modes cause the majority of premature RO membrane and pump failures: dry-running due to low inlet pressure (common when building tanks empty during peak demand periods or PAEW supply interruptions), and membrane damage from excessive high pressure caused by fouled membranes or closed concentrate valves. A low/high pressure switch monitors both conditions simultaneously — the low-pressure cutout stops the RO pump when inlet pressure drops below a set minimum (preventing pump cavitation and dry-running), and the high-pressure cutout stops the pump when system pressure exceeds a set maximum (preventing membrane envelope damage from over-pressure). UV Water Systems in Muscat includes Danfoss-type pressure switches in all commercial and industrial RO system installations as essential safety and protection equipment — the cost of a pressure switch is a fraction of the cost of one pump or membrane replacement.

Danfoss-Type Pressure Switch Design

The Danfoss-type pressure switch (referring to the design standard, not necessarily the brand) uses a stainless steel diaphragm or Bourdon tube connected to a snap-action microswitch through a calibrated spring mechanism. When process pressure crosses the set threshold — rising above the high-pressure setpoint or falling below the low-pressure setpoint — the spring mechanism actuates the microswitch, which opens or closes the electrical circuit controlling the pump or system. Setpoints are field-adjustable using calibration screws and a pressure gauge — UV Water Systems’ technicians calibrate the switch setpoints during system commissioning and verify correct operation by manually pressurising and depressurising the test port. The Danfoss-type design is the industry standard for water treatment pressure switches in Oman due to its reliability, availability of replacement parts, and compatibility with the Grundfos and equivalent pump starter panels used in UV Water Systems’ commercial and industrial installations.

Key Features and Benefits

Dual function — low and high pressure protection: A single switch provides both low-pressure (dry-run protection) and high-pressure (over-pressure protection) cutout in one unit — protecting both the pump (from low pressure) and the RO membrane (from high pressure) with a single field-adjustable instrument.
Field-adjustable setpoints: Both low and high-pressure cutout setpoints are independently adjustable to match the specific system design pressures — UV Water Systems sets these during commissioning and documents the setpoints in the system commissioning record for future reference.
Automatic restart or manual reset options: Configurable for automatic restart after pressure returns to normal (for fully automatic systems with tank level control) or manual reset (requiring an operator to acknowledge the fault and press a reset button before the system restarts) — the manual reset option prevents rapid cycling failures in fault conditions.
Stainless steel diaphragm for compatibility with RO feed water: SS316 wetted diaphragm compatible with chlorinated municipal feed water, RO concentrate, and the full range of water chemistries encountered in residential and commercial water treatment in Oman without corrosion or diaphragm fatigue.
Compatible with standard RO control panel wiring: Normally-open (NO) and normally-closed (NC) contacts on the microswitch connect directly into the control circuit of standard RO pump motor starters and variable speed drives — UV Water Systems technicians install and wire pressure switches during system commissioning without custom panel modifications.

Technical Specifications

Pressure range: 1–10 bar (adjustable setpoints within range)
Low pressure cutout: Adjustable 1–3 bar (typical residential: 2 bar)
High pressure cutout: Adjustable 7–15 bar (typical commercial: 12–14 bar)
Diaphragm material: 316 SS
Electrical rating: 250V AC, 5A
Connection: 1/4-inch BSP/NPT

Applications Across Oman

Danfoss-type pressure switches from UV Water Systems are installed in all commercial and industrial RO systems, water booster pump installations, and water treatment systems with automatic pump control across Muscat. UV Water Systems carries replacement pressure switches in stock for immediate supply on fault-call service visits — contact +968 9763 7786 if your RO system is not auto-starting or is stopping unexpectedly.

Frequently Asked Questions

My RO system is not starting — could the pressure switch be the cause? Yes — a pressure switch tripped on low pressure is one of the most common causes of RO system non-starting in Oman, particularly in buildings where the supply tank has run empty. Check the supply pressure at the system inlet: if below 2 bar, the low-pressure switch has tripped correctly. Restore the supply pressure and reset the switch (press the reset button if manual reset type). If the system still does not start with normal supply pressure, the switch may have failed — call UV Water Systems for a fault diagnosis at +968 9763 7786.

What pressure should the low-pressure cutout be set to for a residential RO system? For a residential under-sink RO system in Muscat with PAEW supply, UV Water Systems sets the low-pressure cutout at 2.0–2.5 bar — above which PAEW supply is consistently available, and below which the inlet solenoid valve and booster pump should not operate. For borehole-fed systems with variable supply pressure, the setpoint may need adjustment based on the borehole pump’s minimum delivery pressure.

UV Water Systems is an ISO 9001:2015 certified water treatment company based in Muscat, Sultanate of Oman, with 14+ years of experience. We supply, install, and service water treatment solutions for residential, commercial, and industrial clients across Oman. Call +968 9763 7786 or visit www.uvwater.biz.

RO Pressure Switch Muscat

Low High Pressure Switch Danfoss Type – UV Water Systems Oman