Gas heater pressure switches are critical safety components that verify proper air or water pressure before allowing burners to operate. This guide compares five widely used replacement switches for residential and pool/spa gas heaters, helping technicians and homeowners identify compatible, reliable parts.
| Product | Brand | Key Feature |
|---|---|---|
| Replacement for Hayward FDXLWPS1930 | usvehj | Designed For Hayward Universal H-Series FD Heaters |
| LEFOO LF31 | LEFOO | Adjustable 0.1″ W.C. To 34″ W.C., SPDT |
| Pentair-Compatible Heater Repair Kit | GOMADEIT | Multi-Part Kit For Pentair Master Temp & Max E |
| 60146 .40″ W.C. Pressure Switch | Allparts Equipment & Accessories | Compact Furnace Compatibility, .40″ W.C. |
| RAMATA 470190 Water Pressure Switch | RAMATA | Pentair PowerMax & MiniMax Plus Compatibility |
Replacement For Hayward FDXLWPS1930 Water Pressure Switch
This replacement switch is specified for Hayward Universal H-Series Low NOx forced-draft pool and spa gas heaters. The listing indicates compatibility with multiple H-Series models and notes it is for heaters made after a specific manufacturing date.
- Compatibility: Works with H150FDN through H400FDP models as listed; use only on heaters made after 5/11/2010 and with “FD” model designation.
- Function: Detects sufficient water pressure/flow and prevents heater ignition when flow is inadequate, protecting burner and components.
- Installation: Described as an affordable, easy-to-install replacement part designed for direct swap in supported heaters.
LEFOO LF31 Water Heater Pressure Switch
The LEFOO LF31 is a versatile pressure switch used across gas furnaces and water heaters. It offers an adjustable set point and hardware for calibration, making it suitable for varied applications.
- Range & Adjustment: Factory set at 50 Pa, adjustable from 0.10″ to 34.0″ W.C., with maximum pressure 40″ W.C.
- Electrical & Contacts: SPDT contact arrangement, rated 5A/24VAC, suitable for many control circuits.
- Included Accessories: Springs and orifice restrictors included for tuning; hardware kit provided for installation.
- Temperature Durability: Rated from -40°F to 190°F, for wide environmental tolerance.
Pentair-Compatible Multi-Part Heater Repair Kit
This kit groups several replacement safety and sensing parts often needed together for Pentair pool and spa heaters. The bundle approach reduces the need to source each item separately during heater servicing.
- Kit Contents: Stack flue sensor, thermistor, pressure switch, high limit switch, and gas shutoff switch (temperatures noted in listing).
- Compatibility: Marketed as compatible replacements for Pentair Master Temp & Max E therm pool heaters and their OEM part numbers.
- Use Case: Useful when multiple interdependent safety parts have reached end of life or during comprehensive heater maintenance.
60146 .40″ W.C. Pressure Switch For Compact Furnace
The Allparts 60146 pressure switch is specified for compact furnaces and small heaters. It is geared toward models used in garages, workshops, and compact heater installations, and supports both natural gas and propane appliances.
- Set Point: Listed as a .40″ W.C. (approx 0.22″ W.C. replacement equivalence noted) for compact furnace applications.
- Compatibility: Works with several compact heater models including MHU45, HSU75 series and similar appliances.
- Application: Replacement part for ENERCO line and related compact furnace systems where a specific low differential is required.
RAMATA 470190 Water Pressure Switch Replacement
The RAMATA 470190 is designed for Pentair PowerMax and MiniMax Plus pool heaters and functions as a flow/pressure interlock to protect the heater burner when water flow is interrupted.
- Designed For: Pentair PowerMax and MiniMax Plus models across several capacity numbers as specified in the listing.
- Function: Shuts off burners if water flow/pressure falls below safe thresholds to prevent overheating and component damage.
- Build Quality: Listing emphasizes upgraded materials, corrosion resistance, and UL certification for safety and durability.
Buying Guide: Choosing The Right Pressure Switch
When selecting a gas heater pressure switch, focus on compatibility, set point range, electrical ratings, and environmental resilience. Below are key considerations and comparison perspectives to guide selection.
1. Compatibility And Model Fit
Match the replacement switch to the heater model and manufacturing period. Manufacturers often specify exact part numbers or model ranges. Using a part outside the specified list can result in improper operation or safety interlocks failing to engage.
2. Pressure Set Point And Range
Different heaters require different differential set points: water-flow switches tend to be binary flow detectors, while air/vent pressure switches often provide adjustable set points (e.g., 0.10″ to 34″ W.C.). Verify the required set point for your system and consider adjustable switches for flexible applications.
3. Electrical Ratings And Contact Type
Confirm the electrical rating (voltage and current) and contact arrangement (SPDT, etc.) to ensure compatibility with your control circuit. Many low-voltage control circuits require 24VAC ratings around 5A; exceeding ratings can damage controls.
4. Environmental And Temperature Ratings
Pressure switches can be exposed to outdoor, attic, or mechanical-room conditions. Check temperature ranges and material corrosion resistance. For pool/spa heaters, corrosion-resistant materials and UL certification indicate suitability for humid environments.
5. Installation And Accessories
Some switches include springs, restrictors, or mounting hardware needed for calibration. Kits that include multiple sensors can simplify maintenance when multiple safety components age simultaneously.
6. Application Type: Water Flow Vs. Air/Vent Pressure
Understand whether the switch needs to detect water flow (common in pool heaters) or air/vent pressure (common in furnaces, tankless water heaters, and vent systems). Water pressure switches monitor flow presence, while vent/air switches monitor draft or fan operation.
7. OEM Versus Aftermarket
OEM replacements may guarantee fitment and adherence to original specifications; aftermarket options can offer broader compatibility and sometimes improved materials. Verify part cross-reference numbers and certification claims when choosing non-OEM parts.
8. Safety And Certification
Look for UL or other recognized certifications, especially for pool/spa and gas appliance components. Certified parts have undergone safety testing relevant to gas ignition and shutoff functions.
9. Troubleshooting And Diagnostics
When diagnosing a pressure-switch-related shutdown, verify tubing, hoses, or ports are clear, ensure proper vacuum/pressure is achieved during operation, and check electrical continuity. Replace the switch when mechanical or electrical failure is confirmed.
10. Cost Of Ownership And Serviceability
Consider the ease of installation and availability of replacement parts. Kits that include multiple sensors can reduce future downtime and shipping delays when several components have similar service life expectations.