Pyro-Chem Two Switch Kit DPDT 551155

The Pyro-Chem 551155 Two Switch Kit provides two factory-approved dual-pole, dual-throw (DPDT) micro switches for Pyro-Chem kitchen fire suppression systems. Each DPDT micro switch provides two independent switch functions — giving the Kitchen Knight II system coordinated control over two separate electrical circuits simultaneously during a system discharge. Common applications include electrical appliance shutdown (cutting power to cooking equipment), exhaust fan control, alarm signalling, and other auxiliary interlocks that must respond automatically when the suppression system activates.

The dpdt micro switch configuration is specifically required for installations where two separate, independently controllable electrical circuits must respond to a single system discharge event. Unlike a single-pole switch that controls one circuit, the DPDT dpdt switch provides two independent contact sets — each with normally-open and normally-closed positions — allowing the system to simultaneously shut down cooking equipment and activate an alarm, or control two separate ventilation zones, from a single actuation signal.

For fire protection contractors completing Pyro-Chem Kitchen Knight II installations, the 551155 two switch kit ensures the system's auxiliary interlock capabilities are fully configured with factory-listed switch hardware. Authorized pyro chem distributors carry the 551155 as a standard pyro chem fire suppression system parts item. The pyro chem kitchen knight manual provides the wiring specifications for the two-switch configuration in Kitchen Knight II systems. Semi-annual testing per NFPA 17A and NFPA 96 must verify both DPDT switch functions operate correctly during a simulated system discharge test.

Wiring Configuration

Install each DPDT micro switch per the pyro chem kitchen knight manual wiring diagram. Each switch has six terminals — two poles each with normally-open (NO), normally-closed (NC), and common (C) contacts. Map each contact set to the correct auxiliary circuit per the system design drawings. Verify polarity and circuit assignment at the Pyro-Chem control head before completing the installation. Document all switch wiring assignments in the system installation record.

Semi-Annual Testing

Test both DPDT switch functions at every semi-annual NFPA 17A and NFPA 96 inspection. Trigger a simulated system discharge and verify both switch contacts change state correctly — confirming all connected auxiliary circuits respond as designed. A switch that fails to actuate correctly during testing is an immediate red-tag deficiency requiring switch replacement with new 551155 OEM hardware. Document both switch test results in the fire suppression system inspection record.

Can I use a single DPDT switch instead of two?

The 551155 kit includes two DPDT micro switches to provide four independent contact sets — two per switch. If only two independent circuit functions are needed, one DPDT switch may be sufficient. If four independent circuit functions are needed, both switches are required. Verify the number of auxiliary interlock circuits required by the system design and local AHJ before specifying the switch configuration. The pyro chem kitchen knight manual provides configuration guidance.

Can generic DPDT switches be used instead of the 551155 kit?

No. The 551155 OEM switches are specifically rated and listed for Pyro-Chem Kitchen Knight II system actuation forces and operating conditions. Generic dpdt switch components may not meet the mechanical actuation force, temperature rating, or cycle life required for fire suppression applications. Using non-OEM switches voids the system's UL 300 listing. Source through authorized pyro chem distributors only.