Product Overview

Spirax Sarco KB33 cast iron self-acting control valve is a normally open, two-port valve. Used in conjunction with Spirax Sarco SA control systems, this unit provides self-acting temperature control for steam, water, and other non-hazardous Group 2 fluids.

Key Features

• Normally open configuration.
• Phosphor bronze balancing bellows enables operation against higher differential pressures up to 10.3 bar.
• Flanged connections to EN 1092 PN16 and BS 10 Table F.
• Complies with the requirements of the European Pressure Equipment Directive 2014/68/EU.

Technical Specifications

Specification	Value
Body Material	Cast iron (DIN 1691 GG 25)
Sizes	DN25, DN32, DN40, DN50
Body Design Conditions	PN16
Maximum Design Pressure	16 bar g @ 120°C
Maximum Design Temperature	220°C @ 13.8 bar g
Minimum Design Temperature	-10°C
Maximum Operating Temperature	220°C
Minimum Operating Temperature	0°C
Maximum Differential Pressure	10.3 bar (DN25), 9.0 bar (DN32), 8.2 bar (DN40), 6.9 bar (DN50)
Kv Values	9.80 (DN25), 16.48 (DN32), 23.70 (DN40), 34.00 (DN50)

Applications

• Self-acting temperature control units when paired with SA control systems.
• Steam and water systems.
• Non-hazardous fluid control (Group 2).

Materials and Parts

Part	Material	Standard
Body	Cast iron	DIN 1691 GG 25
Bonnet	Cast iron	DIN 1691 GG 25
Valve head	Stainless steel	BS 970 431 S 29
Valve seat ring	Stainless steel	BS 970 431 S 29
Valve seat gasket (DN25)	Mild steel	BS 1449 CS 4
Valve seat gasket (DN32-DN50)	Reinforced exfoliated graphite	-
Return spring	Stainless steel	BS 2056 302 S 26
Stem	Brass	BS 2874 CZ 121
Bellows	Phosphor bronze	EN 12449 Cu Sn 6

Dimensions and Weights

Size	PN16 A1 (mm)	BS 10 ‘F’ A1 (mm)	B (mm)	C (mm)	Weight (kg)
DN25	160	157	138	51	5.9
DN32	180	180	152	51	9.1
DN40	200	200	152	62	11.2
DN50	230	230	152	71	13.4