Series 537

Kunkle Safety and Relief Products
Models 537
ASME Section IV, Low Pressure Steam and
Hot Water Boilers, “HV” National Board Certified,
Safety Relief Valves
Features
• Extra heavy construction helps
provide long life.
• Top guided disc assembly
incorporates resilient seal in seating
area.
• An isolating diaphragm protects
working parts from corrosion caused
by discharged liquid.
• Pivot between disc and spring
designed to correct for misalignment
and compensates for spring side
thrust.
• These safety relief valves serve
the dual purpose of relieving (1)
overpressure created by thermal
expansion under normal “on” and
“off” firing conditions, and (2)
overpressure in the form of water or
steam created in over-firing due to
failure of electrical or other controls.
• Each Kunkle valve is tested and
inspected for pressure setting and
leakage.
Applications
Hot water boiler, heat exchangers and
generators.
Pressure and Temperature Limits
15 to 160 psig
-20° to 250°F
Kunkle Safety and Relief Products
Model 537
Parts and Materials
Model 537
11
No. Part Name
Materials
10
1
Body
1
2
3
Seat O-ring
Seat
BUNA-N2
Bronze, B584 Alloy 844002
9
Bronze, B584 Alloy 84400
Ethylene Propylene (EPDM)
BUNA-N/Nylon
Brass, B36 Alloy C26000
Brass, B16
SS
8
5
Disc Holder
Insert
Diaphragm
Guide
Lock Nut
Screw
6
7
Spring
Bonnet
1
8
9
Spring Step
Compression Screw
Brass, B16
Brass, B16
7
10
11
Lever
Seal and Wire
Steel, Zinc Plated
Lead seal and SS wire
6
12
13
Lift Washer Nut
Lift Washer
SS
SS
14
Stem
Spring Pin
Disc Locknut
SS, A479-316
SS
Brass
4
12
13
14
SS, A313-631
5
4
3
Notes
1.
2
3/4"
and 1": Bronze, B584 Alloy 84400
11/2" and 2": Cast Iron, A126 Class A/B
1
2. D and E orifice sizes have an integral seat.
G and H orifice sizes have an insert seat
above a BUNA-N O-ring body seal.
Specifications
Size
Inlet
3/4"
Outlet
–––––––– Dimensions, in ––––––––
A
B
C
17/8
61/8
2
1"
11/2"
11/4"
15/16
2 3/8
2"
13/4
215/16
71/8
101/8
5
12
2"
21/2"
21/8
3 9/16
113/4
22
1"
15/16
Weight
(lb)
C
Dimensions are for reference only.
A
B
Kunkle Safety and Relief Products
Model 537
Capacities
ASME Section IV Steam (Hot Water Boiler)
Set Pressure
(psig)
————————————–––––———— Orifice Area, in2 ————————–––––—————————
3/4"
1"
11/2"
2"
(0.533 in2)
(0.833 in2)
(1.767 in2)
(3.142 in2)
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
30
812
1055
811962
1055329
1269
1649
1268976
1649323
2692
3499
2691813
3498623
4786
6221
4786461
6221095
40
50
1299
1542
1298696
1542064
2030
2410
2029670
2410017
4305
5112
4305434
5112244
7656
9090
7655729
9090363
60
70
1785
2029
1785431
2028798
2790
3171
2790364
3170711
5919
6726
5919055
6725865
10525
11960
10524997
11959631
80
90
2272
2516
2272165
2515533
3551
3931
3551058
3931405
7533
8339
7532676
8339486
13394
14829
13394265
14828899
100
110
2759
3002
2758900
3002267
4312
4692
4311752
4692098
9146
9953
9146296
9953107
16264
17698
16263533
17698167
120
125
3246
3367
3245634
3367318
5072
5263
5072445
5262619
10760
11163
10759917
11163323
19133
19850
19132801
19850119
130
140
3489
3732
3489002
3732369
5453
5833
5452792
5833139
11567
12374
11566728
12373538
20567
22002
20567436
22002070
150
160
3976
4219
3975736
4219103
6213
6594
6213486
6593833
13180
13987
13180349
13987159
23437
24871
23436704
24871338
Kunkle Safety and Relief Products
Model 537
Model Number/Order Guide
Model Number
Position
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
Example
0
5
3
7
— D
0
1
—
H
Model
0537
Inlet Size
D
E
G
H
- 3/4"
- 1"
- 11/2"
- 2"
Variation
01 - Catalog Standard
Design Revision
Indicates non-interchangeable revision.
Dash (-) if original design.
Service
H - Steam ASME Section IV - hot water
Spring Material
M - SST
Set Pressure
15 psig (0015)
160 psig (0160)
M
0
1
6
0