Available Special Features are based on the type of pressure switch and housing option. Not all special features are available for all models. Use our Pressure Switch Configuration Worksheet as a guide to configuring a Solon Pressure Switch. For additional support or questions determining which Special Features are suitable for your application, please contact techsupport@solonmfg.com.

“-“     NO SPECIAL FEATURES

   ADJUSTABLE DEAD BAND – Specified with one electric switch (or II) the tandem electrical switches, the snap-over pressure minus the snap-back pressure is adjustable. The range of this adjustment is between 10% and 50% of the specified pressure range. The adjustable deadband is above the decreasing pressure set point; (i.e. if the pressure is set at 50 psi decreasing pressure, and the deadband is adjusted to 20 psi, the electric switch will snap-over at 70 psi increasing pressure and snap-back at 50 psi).
NOTE: The “A” special feature cannot be combined with special features 2, 3, 4, BDD, DD, Q, R, and is not recommended for 7PS ranges 1.5, 3, and 6 WC.
B    BELLOWS ACTUATED -  Bellows actuation is required for all pressure ranges above 300 psi, or where all metal pressure sensing elements are required. Standard bellows assemblies are constructed using stainless steel bellows brazed into stainless steel housings. All welded bellows assemblies are available – consult factory. The movement of the mechanism requires less than 15% of the maximum bellows stroke – this means exceptionally good life. The small fluid displacement required to operate these bellows assemblies make them easy to apply to all types of protective diaphragm seals.

BD     BELLOWS ACTUATED DIFFERENTIAL PRESSURE (DP) – Opposed bellows assemblies sense the difference between pressure sources (DP). These are the same stainless steel bellows assemblies as described above. Both the High and Low-pressure bellows assemblies can withstand the Maximum Allowable Pressure with the opposite bellows assembly at atmospheric pressure.

D    DIAPHRAGM ACTUATED DIFFERENTIAL PRESSURE (DP) – Opposed diaphragm areas sense the difference between pressure sources (DP). Both the High and Low-pressure areas can withstand the Maximum Allowable Pressure with the opposite side at atmospheric pressure.

E    EXTERNAL PRESSURE ADJUSTMENT – This nut allows adjustment of the set point in the field without removing the cover. Pressure and Differential Pressure Models use adjustment nuts with micrometer markings which allow reasonably good pressure settings without the use of a gauge. Vacuum and Special Switches may have nuts supplied without micrometer markings. External adjustment nuts are typically used on models with one electric switch or tandem (II) electric switches. They can be used on models with 2, 3, 4 electric switches, but cannot be supplied with micrometer markings when used this way.

EE    TWO EXTERNAL PRESSURE ADJUSTMENTS – This special feature is used in combination with “A” adjustable Dead Band where it is necessary to adjust both the set point and the Dead Band externally.
NOTE: The EE feature cannot be combined with special features 2, 3, 4, BDD, DD, Q, R.
F    FLANGE BASE MOUNTING – Models constructed with a flange base will bolt directly to a standard flange. 6PS Models mate with a 1-1/2”-150# ASA flange. 7PS Models mate with a 5”-150# ASA flange. These are diaphragm actuated switches available in the ranges with specifications given in the model series tables.
NOTE: The F special feature cannot be combined with B, BD, BDD, D, M, P.
G    DOUBLE DIAPHRAGM – This special feature is designed to double the sensitivity of low range 7PS Models 1.5, 3, 6, 15 WC. Two main diaphragms are operated in parallel which doubles the area and force available to operate the mechanism. The fixed Dead Bands become half of what appear in the 7PS table. Combining G with “A” adjustable Dead Band helps to make “A” more practical for use in the lower pressure ranges.
NOTE: Special feature G cannot be combined with special features DS, F, S.
DG    DOUBLE DIAPHRAGM DIFFERENTIAL PRESSURE (DP) – This is the same special feature as described above for differential pressure applications.

J    SAFETY SEAL – This special feature installs a seal between the switch housing and the atmospheric side of the main diaphragm. A ¼ NPT connection vents this cavity.
NOTE: The J special feature cannot be combined with D, DD, DS.
LL    INDICATOR LIGHTS – One of two indicator lights can be specified to give visual indication of pressure setting. 5PS Models use neon lights mounted on the cover. 6PS and 7PS Models use ¾” jewels (clear, red, green, amber) mounted on the cover and separate 6 watt instrument lamps mounted in the switch housing. This special feature is useful when combined with (2) independently adjustable electric switches where the lights can show the pressure within a normal range or the lights can show the pressure too high or too low. Specify color of the light jewels when ordering this special feature.
NOTE: Indicator lights cannot be furnished on “X” explosion-proof housings.
M    MALE PIPE MOUNTING – This ½ NPT male pipe fitting is rigidly attached to the pressure switch. It can be used to mount the switch directly on a pipe or where a ½” pressure connection is required.

O    HIGH OVER PRESSURE DIAPHRAGM – This special feature incorporates a diaphragm which is fully supported during an overpressure. The support allows the diaphragm to withstand extremely high pressures and return to normal operation. Model 2PS and some Model 5PS switches are available with this special feature.

R>    MANUAL RESET, SWITCH ON INCREASE PRESSURE – Indicates a manual reset when there is an increase in pressure.

R<    MANUAL RESET, SWITCH ON DECREASE PRESSURE – Indicates a manual reset when there is a decrease in pressure.
Note: The R special feature cannot be combined with A, EE, Q.
S[ ]    SPECIAL TRIM BASE – Applied to diaphragm-actuated pressure switches, special trim base allow the wetted area to be constructed with material other than the standard aluminum alloy. Code symbols for materials available are as follows:

SS    316 stainless steel

SN    Brass

SI    Teflon. Max. Pr.  50 psi – 2PS & 6PS models
                 15 psi – 7PS models

SY    PVC. Max Pr.  100 psi – 2PS & 6PS models
               25 psi – 7PS models
    Note: Special feature SI and SY cannot be furnished on explosion-proof housing – Consult factory.
T     TEFLON PROTECTED DIAPHRAGM – This is a Teflon face which protects the diaphragm on the wetted side.

U    SPECIAL EXPOXY PAINT – The entire assembled pressure switch is given a coat of standard one part epoxy paint. For more severe applications, a special two-part epoxy paint is available – consult factory.

V HIGH-TEMPERATURE SERVICE – The pressure switch is constructed with high-temperature electric switches, diaphragms, and gaskets for service where the fluid operating the switch does not exceed 300ºF and the temperature surrounding the switch does not exceed 250ºF. Not a UL-listed feature. 

Z    VITON DIAPHRAGM – Viton diaphragm material replaced the standard Buna N diaphragm material.

UNIQUE DIFFERENTIAL PRESSURE SWITCH FEATURES

BDD    BELLOWS ACTUATED TWO-WAY DIFFERENTIAL PRESSURE (DP) – These Differential Pressure Switches are constructed to sense a differential pressure in two directions. Both pressure sources can become higher relative to the other, and bellows actuated electric switch operation will occur. This special feature must be specified with at least two (2) electric switches – one for either direction. When specified with four (4) electric switches, two electric switches are available for operation in either direction. 
Note: The BDD special feature cannot be combined with special feature A, E, EE, Q.
DD    DIAPHRAGM ACTUATED TWO-WAY DIFFERENTIAL PRESSURE (DP) – These Differential Pressure Switches are constructed to sense a differential pressure in two directions. Both pressure sources can become higher relative to the other, and diaphragm actuated electric switch operation will occur. 

DDG     DOUBLE DIAPHRAGM TWO-WAY DIFFERENTIAL PRESSURE (DP) – Sensitive two-way differential pressure is achieved by using double diaphragms as described by Special Features G and DG.

DO    HIGH-PRESSURE – LOW DIFFERENTIAL PRESSURE (DP) – DO type differential pressure switches are designed to sense low differential pressure (DP) between high-pressure sources. The 6PS and 7PS models use opposed stainless steel bellows assemblies for the high-pressure seals, while the differential pressure is sensed by a diaphragm clamped between the bellows assemblies. The diaphragm has a large area to accurately sense low differential pressure, and during an over-pressure, the diaphragm is fully supported. The differential pressure assembly is symmetrically designed such that both the High and Low-pressure areas can withstand the Maximum Allowable Pressure with the opposite side at atmospheric pressure. The standard trim base used for DO switches is a strong aluminum alloy. Other materials are available which are described by the following code symbols:

DOSS    316 stainless steel trim base.

DOSN    Brass trim base.

DDO    HIGH-PRESSURE TWO-WAY DIFFERENTIAL PRESSURE (DP) – DO type switch which will sense differential pressure in either direction. Also available are DDOSS and DDOSN models.

DS[ ]    SPECIAL TRIM DIAPHRAGM DIFFERENTIAL PRESSURE (DP) – These diaphragm-actuated differential pressure switches are designed with special trim which allows the wetted area to be constructed with material other than the standard aluminum alloy. The code symbols for these materials are as follows:

DSS    316 stainless steel.

DSN    Brass.

DSI    Teflon.     Max. Pr. 50 psi – 2PS & 6PS models.
                        25 psi – 7PS models.

DSY    PVC. Max. Pr. 100 psi – 2PS & 6PS models.
              50 psi – 7PS models.
Note: Some DS [ ] models have higher maximum allowable pressures. If this feature is of primary interest in the selection of a switch, use the following code symbol “DSK”.
DSK    Aluminum trim base with higher than normal maximum allowable pressure. See range table on the differential spec sheets for particulars.