UK Product Handbook 2026 - Volume 1

Control systems Self-acting controls

4

Local regulations may restrict the use of this product to below the conditions quoted. In the interests of development and improvement of the product, we reserve the right to change the specification without notice. © Copyright 2025

TI-P078-02 CTLS Issue 14

KA31, KA33, KB31 and KB33 Cast Iron Self-acting Control Valves

KB31 and KB33 balanced trim

4.5 27

KA31 and KA33 unbalanced trim

Description The KA and KB range of two-port valves are used in conjunction with Spirax Sarco SA control systems to provide a self-acting temperature control unit. Available types KA31 Normally open with screwed connections. Note:

Pressure balancing bellows enables the valve to operate against higher differential pressures.

KA33

Normally open with flanged connections.

KB31

Normally open with phosphor bronze balancing bellows and screwed connections.

KB33

Normally open with phosphor bronze balancing bellows and flanged connections.

Standards These products fully comply with the requirements of the European Pressure Equipment Directive 2014/68/EU and carry the mark when so required. Certification As standard these products are available with a manufacturers’ Typical Test Report. Note: All certification/inspection requirements must be stated at the time of order placement.

Sizes and pipe connections Screwed BSP T Rp (ISO 7-1) (BSP parallel) or NPT:

Flanged EN 1092 PN16 and BS 10 Table F:

KA31 ½ ", ¾ ", 1", 1 ¼ ", 1 ½ " and 2"

KA33 DN15, DN20, DN25, DN32, DN40 and DN50

KB31 1", 1 ¼ ", 1 ½ " and 2"

KB33 DN25, DN32, DN40 and DN50

TI-P078-02 CTLS Issue 14

Page 1 of 5

KA31, KA33, KB31 and KB33 Cast Iron Self-acting Control Valves

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