Brochure

Bulletin-MC-INST-MMA-0615
Warranty & Engineering Data
ADJUSTING ROOM TEMPERATURE
Set the dial on the thermostat to achieve the desired temperature as indicated by
the charts below.
MTW Series Thermostats
Dial Setting 0 * 1 3 5 6 7 8 9
Room Temperature (ºF) Off 46 54 61 68 72 76 80 82
INSTALLATION EXAMPLES (Direct Mount)
RECOMMENDED NOT RECOMMENDED
RECOMMENDED NOT RECOMMENDED
Vertical angle valve with
straight nipple. NPT -
female inlet, male union
outlet.
1/2” N10637
3/4” N10657
1” N10677
1-1/4” N10697
Straight valve with
straight nipple. NPT -
female inlet, male union
outlet.
1/2” N10737
3/4” N10757
1” N10777
1-1/4” N10797
Horizontal angle valve
with straight nipple. NPT -
female inlet, male union
outlet.
1/2” N10837
3/4” N10857
1” N10877
1-1/4” N10897
Sweat valve with female
inlet and outlet.
1/2” N10930
3/4” N10950
1” N10970
NT SERIES VALVES Valve bodies for MTW & NT series thermostats are non-electric temperature
control valves for radiators, convectors, fan coil units and hydronic central heating systems. The valve can be
actuated by a handknob or thermostats with remote or direct sensors or VM electric actuators.
MTW SERIES THERMOSTATS MTW & ENT Series Thermostats are installed on NT series
valves to automatically control the actions of the valve, thus monitoring room temperature and conserving fuel.
MTWZ
Nonelectric, fully automatic thermostat
with valve mounted temperature setting
dial and remote sensor.
ENTL-B46000
Nonelectric, fully automatic remote
thermostat with remote sensor and
temperature setting dial.
Zone Control ZMC-ES & ZMC-DDC
Electric zone actuator with end switch
(ES) or proportional (DDC).
MTW
A non-electric positive mechanical shut-
off direct mounting thermostat. Anti-
freeze position and adjustable maxi-
mum / minimum temperature. Highly
sensitive with very accurate temperature
settings and reactions.
ENTLZ-B56000
Non-electric, fully automatic thermostat
with separate remote sensor and remote
temperature setting dial.
Zone Control VMC-24 & VMO-24
24-volt electric zone control for control-
ling individual room temperatures or
zones (VMC-24 Normally Closed &
VMO-24 Normally Open).
SYMPTON POSSIBLE REASON SOLUTION
Not all sections of radiator heating up 1. Many radiators are over-sized and all sections are not
required to heat up to maintain the set room tempera-
ture.
1. System is "A" OK.
Underheating 1. Sensor in the wrong location.
2. Thermostatic control mounted in vertical position.
3. Remote sensor located in convector or near heat
source.
4. Flow through valve is in the wrong direction.
5. Inadequate system temperature or pressure.
6. Steam traps defective.
7. Air lock in hot water system.
8. Scale or debris blocking flow.
9. Heating cabinet dampers are closed.
1. Change the sensor location, or control type. See installation
instructions.
2. These control types must be mounted horizontally.
3. Remove sensor away from direct heat source.
4. Check arrow on valve body. It should be in the direction of
flow. Change valve direction, or flow direction.
5. Check operating and limiting controls on boiler. Check
circulating pump and isolating valves.
6. Repair or replace traps with Tunstall traps.
7. Open valve fully to allow air to pass. Install vents.
8. Flush System. Do not use oil base additives.
9. Open or remove dampers.
Overheating 1. Sensor in the wrong location.
2. Control not properly installed.
3. Capillary tube broken, kinked, or bent sharply.
4. Dirt or scale under seat, preventing tight shutoff.
5. Flow through valve is in the wrong direction, damag-
ing the valve seat.
6. Steam traps defective.
7. Excessive differential pressure is forcing valve open.
(Hot water systems)
1. Change sensor location, or change control type.
2. Set bosses in grooves and tighten knurled ring to valve body.
Do not over tighten.
3. Replace control.
4. Remove control from valve body, allowing valve to open
fully and flush away scale and debris. Reinstall control and
turn fully clockwise. If valve does not fully close, remove
control and inspect valve seat area using cartridge changer
tool or service socket tool. Change insert assembly.
5. Check arrow on valve body. It should be in the direction of
flow. Change valve direction, or flow direction. Remove
valve cartridge and inspect for damage to seat disc.
6. Repair or replace traps with Tunstall traps.
7. Install differential pressure regulator to maintain less than
2.9 psi differential between supply and return pipes.
Chattering or knocking 1. Flow through valve is in wrong direction.
2. Vacuum in system.
3. Excessive differential pressure.
(Refer to Valve/T'Stat Specifications)
4. Binding of piping.
1. Check arrow on valve body. It should be in the direction of
flow.
2. Steam - Check traps and vents. Hot water - check expansion
tank operation and location.
3. Install differential pressure regulator to maintain less than
2.9 psi differential between supply and return pipes.
4. Ensure adequate space for piping.
TROUBLE SHOOTING GUIDE