MODEL 537 SAFETY RELIEF VALVE

Features

• Extra heavy construction helps provide long life.

• Top guided disc assembly incorporates resilient seal in seating area.

• Isolating diaphragm protects working parts from corrosion caused by discharged liquid.

• Pivot between disc and spring designed to correct misalignment and compensates for spring side thrust.

• Heavy duty lift lever.

• Tested and inspected for pressure setting and leakage.

GENERAL APPLICATION

These valves serve the dual purpose of relieving overpressure created by thermal expansion under normal firing conditions and overpressure in the form of water or steam created in over-firing due to failure of electrical or other controls on hot water boilers, heat exchangers and generators.

TECHNICAL DATA

Connections:	FNPT
Temperature range:	-20° to 250°F (-29° to 121°C)
Pressure range:	15 to 160 psig (1.0 to 11 barg)
Code:	ASME IV

PARTS AND MATERIALS

No.	Part Name	Materials
1	Body	[1]
2	Seat o-ring	NBR^[2]
3	Seat	Bronze, B584 alloy 84400^[2]
4	Disc holder Insert Diaphragm Guide Lock nut	Brass, B16^[3] Ethylene propylene (EPDM) NBr/nylon Brass, B36 alloy C26000^[4] Brass, B16
5	Screw	SS
6	Spring	SS, A313-631
7	Bonnet	[1]
8	Spring step	Brass, B16
9	Compression screw	Brass, B16
10	Lever	Steel, zinc plated
11	Seal and wire	Lead seal and SS wire
12	Lift washer nut	SS
13	Lift washer	SS
14	Stem Spring pin Disc locknut	SS, A479-316 SS Brass

NOTES

1. ¾” and 1”: bronze, B584 alloy 84400.

1½” and 2”: cast iron, a126 class a/B.

2. ¾” and 1″ sizes have an integral seat. 1½” and 2″ sizes have an insert seat

above a NBr o-ring body seal.

3. 1½” size: brass, B283 alloy 37700.

2″ size: bronze, B584 alloy 84400.

4. ¾” size: brass, B16.

SPECIFICATIONS

Size			Dimensions (in)		Weight
Inlet	Outlet	A	B	C	(lb)
¾”	1”	15/16	1⅞	6⅛	2
1”	1¼”	1^5/16	2⅜	7⅛	5
1½”	2”	1¾	2^5/16	10⅛	12
2”	2½”	2⅛	3^9/16	11¾	22

Capacities

ASME SECTION IV STEAMM (Hot water boiler)

					Orifice	area,	in²
		¾”			1”			1½”			2”
Set pressure		(0.533 in²)			(0.833 in²)			(1.767 in²			(3.142in²
(psig)	lb/h		BTU/h	lb/h		BTU/h	lb/h		BTU/h	lb/h		BTU/h
15	690		690278	1079		1078802	2288		2288408	4069		4069144
20	812		811962	1269		1268976	2692		2691813	4786		4786461
30	1055		1055329	1649		1649323	3499		3498623	6221		6221095
40	1299		1298696	2030		2029670	4305		4305434	7656		7655729
50	1542		1542064	2410		2410017	5112		5112244	9090		9090363
60	1785		1785431	2790		2790364	5919		5919055	10525		10524997
70	2029		2028798	3171		3170711	6726		6725865	11960		11959631
80	2275		2272165	3551		3551058	7533		7532676	13394		13394265
90	2516		2515533	3931		3931405	8339		8339486	14829		14828899
100	2759		2758900	4312		4311752	9146		9146296	16264		16263533
110	3002		3002267	4692		4692098	9953		9953107	17698		17698167
120	3246		3245634	5072		5072445	10760		10759917	19133		19132801
125	3367		3367318	5263		5262619	11163		11163323	19850		19850119
130	3489		3489002	5453		5452792	11567		11566728	20567		20567436
140	3732		3732369	5833		5833139	12374		12373538	22002		22002070
150	3976		3975736	6213		6213486	13180		13180349	23437		23436704
160	4219		4219103	6594		6593833	13987		13987159	24871		24871338

SELECTION GUIDE

Example:	0537	-	D	01	-	H	M	0160
Model 0537
Connection size D ¾" inlet x 1” outlet E 1" inlet x 1¼” outlet G 1½" inlet x 2” outlet H2" inlet x 2½” outlet
Variation 01 Catalog standard
Design revision Indicates non-interchangeable revision - Original design (connection sizes E, G and H) A Revision A (connection size D)
Service H Steam ASME section IV - hot water
Spring material M SST
Set pressure 0015 15 psig 0160 160 psig