Spirax Sarco ST17 sensor chambers are an integral part of the Spiratec trap fault detection system, designed specifically for use on saturated steam systems. These chambers enable the monitoring of steam trap performance, identifying whether a trap is leaking steam or has failed closed/blocked when used in conjunction with appropriate sensors and monitors.

The ST17 features an SG iron body and is available in sizes DN15 to DN25 with screwed connections. As standard, the sensor connection is located on the right-hand side when viewed from the direction of flow, with left-hand configurations (ST171L) available upon request.

Sensor Configurations

Chambers can be supplied in two primary configurations depending on the monitoring requirement:

• With SS1 Standard Sensor: For steam leak detection only. Typically supplied pre-fitted.
• Without Sensor: Prepared for on-site fitting of a WLS1 Waterlogging Sensor Assembly, which enables detection of both steam leaks and waterlogging (traps failed closed or blocked).

Pressure and Temperature Limits

Condition	Value
Body design conditions	PN40
PMA Maximum allowable pressure	32 bar g (464 psi g)
TMA Maximum allowable temperature	240°C (464°F)
PMO Maximum operating pressure	32 bar g (464 psi g)
TMO Maximum operating temperature	240°C (464°F)
Cold hydraulic test pressure (without sensor)	60 bar g (870 psi g)
Cold hydraulic test pressure (with sensor)	32 bar g (464 psi g)

Materials

Part	Material	Standard
ST17 Body	SG Iron	DIN 1693 GGG 40
SS1/WLS1 Sensor Body	Stainless steel	BS 970, 303, S31 and PEEK
Sensor Gasket	Stainless steel	BS 1449 304 S16
Plug	Stainless steel	BS 970 431 S29

Installation and Maintenance

The sensor chamber must be installed immediately upstream of the steam trap in a horizontal pipeline. Ensure the drain plug is facing downwards and the direction of flow matches the arrow on the body.

Installation Space

Ensure adequate space is provided for the removal of the sensor from the chamber body during maintenance.

Sensors should be removed periodically to inspect and clean the insulator. When refitting, always use a new gasket and tighten to a torque of 50 - 56 N m.