Brochure
Table Of Contents
Tunstall Corporation 
118 Exchange Street • Chicopee, MA 01013 
© July 2014 
We reserve the right to alter designs, specifications and information without notice. 
Phone (413) 594-8695 · Fax (413) 598-8109 
www.tunstall-inc.com • www.maconcontrols.com 
Bulletin-MC-NTCT-0714 
Valves 
CAPACITY TABLES for 
 ”NT” SERIES VALVES
P.D.* with 
10 PSI Inlet 
3.5 C
v
1-1/4” Valves 
2.74 C
v
1” Valves 
2.5 C
v
3/4” Valves 
1.8 C
v
1/2” Valves 
1 psi  48,000 39,000 36,000 28,000 
3 psi  87,000 70,000 65,000 46,000 
5 psi  113,000  91,000  84,000  63,000 
7 psi  130,000  104,000  96,000  72,000 
10 psi  162,000 130,000 120,000  90,000 
STEAM 
BTU/hour 
*P.D. = Pressure Drop 
Capacity measured with 10 psi inlet pressure. 
EDR = Equivalent Direct Radiation (in ft.
2
) 
EDR =    BTU/hr = 240 x EDR 
BTU/hour = lbs. steam/hour x 1000 
240
BTU/hr
HOT WATER 
BTU/hour** 
** Pressure Drop 
Ft. 
P.D. 
PSI 
3.5 C
v
1-1/4” Valves 
2.74 C
v
1” Valves 
2.5 C
v
3/4” Valves 
1.8 C
v
1/2” Valves 
1  .43  21,000 17,000 16,500 12,000 
2  .87  28,000 23,000 22,000 15,500 
4  1.7  44,000 35,000 32,500 23,500 
6  2.6  53,000 43,000 40,000 29,000 
8  3.5  64,000 51,000 47,000 33,500 
10  4.3  70,000 56,000 52,000 37,500 
12  5.2  77,000 62,000 57,000 41,000 
14  6.1  83,000 67,000 62,000 44,500 
16  7.0  88,000 71,000 66,000 47,500 
** Assumes 20°F drop in water temperature through radiation. 
GPM = C
v 
 1psi = 2.31 Ft. H
2
O 
BTU/hour = GPM x 10,000 1Ft. H
2
O = .433 psi 
..DP
EDR (Equivalent Direct Radiation in ft.
2
) for Hot Water 
Water Temperature  Cast Iron Radiator  Convector 
200°F 209  205 
190°F 187  183 
BTU/hour = EDR in ft.
2
 x (Appropriate number from above EDR Table) 
For example: 205 for 200°F water in convector 










