Brochure
Table Of Contents
Tunstall Corporation 
118 Exchange Street • Chicopee, MA 01013 
© July 2014 
Phone (413) 594-8695 · Fax (413) 598-8109 
www.tunstall-inc.com • www.maconcontrols.com 
Bulletin-MC-NTV-0714 
Valves 
NT SERIES VALVES 
Operation 
The Macon valve is designed to save energy by 
controlling hot water or low pressure steam heat in 
freestanding radiators, convectors, baseboards, fan 
coil units and the like in a loop, a zone or a unit. 
The valve, coupled with a Macon operator, pro-
vides a reliable automatic modulating unit. As room 
temperature drops, the Macon valve opens to allow 
more hot water or steam to flow through the radia-
tor, thus allowing more heat into the room. When 
the room approaches the selected temperature, the 
operator causes the valve to begin closing off the 
flow of hot water or steam. This continued monitor-
ing of the temperature is fully automatic, using no 
electricity whatsoever. The Macon valve can be 
equipped with any wide variety of Macon opera-
tors. 
Features 
 Compact dimensions 
 Replaceable insert 
 Stainless steel spindle 
 Individual room control 
 Easy one-trade installation 
 Fuel savings up to 30% 
 Prevents over- and under-heating 
 Helps balance the heating system 
 Same valve used for hot water or low pressure 
steam 
 All NPT are forged brass nickel-plated 
 Minimizes or eliminates expansion noises 
 Suitable for nearly any hydronic heating appli-
cation 
 Operators can be changed without draining the 
system 
 Shipped with a protective cap that can be used 
to control heating during the installing period 
Vertical angle valve with straight nipple. NPT - female inlet, 
male union outlet. 
N10637 - 1/2” 
N10657 - 3/4” 
N10677 - 1” 
N10697 - 1-1/4” 
Straight valve with straight nipple. NPT - female inlet, male 
union outlet. 
N10737 - 1/2” 
N10757 - 3/4” 
N10777 - 1” 
N10797 - 1-1/4” 
Horizontal angle valve with straight nipple. NPT - female 
inlet, male union outlet. 
N10837 - 1/2” 
N10857 - 3/4” 
N10877 - 1” 
N10897 - 1-1/4” 
Sweat valve with female inlet and outlet. 
N10930 - 1/2” 
N10950 - 3/4” 
N10970 - 1” 
Fail closed valves also available, consult factory. 
All Macon valves and thermostats conform to ASHRAE Standard 102P-1983 
and European Standard EN 215/1215. We are also ISO 9001 certified (1994) 
and ISO 14001 certified (1998). 
A
B
C
D
FLOW
FLOW
FLOW
FLOW
= VALVE
VALVE LOCATION IN SINGLE AND
MULTIZONE HEATING SYSTEMS.










