Siemens Powers 832-177 Technical Bulletin page 11

Calibration Kit for Room and Duct Thermostats
TH-182DN and
TH-182 DNV Day-
Night and Day-Night
Vent Thermostats,
Continued
If control pressure remains
at 1/2 psi (3.4 kPa)
If control pressure remains
at maximum 18 or 25 psi
(124.0 or 172.2 kPa)
If excessive Air Leakage
from Nozzle—Control
Pressure Does Not Drop
Siemens Industry, Inc.
1. Use either 18 psi (day) or 25 psi (night) (124.0 or 172.2 kPa) air supply.
2. Remove the thermostat cover and connect the pressure gauge. See Thermostat
Calibration, Steps 1 through 4.
3. Check the throttling pin to see if it is in place under the center leg of the bi-metal
element.
4. Use the Cover screw and calibration wrench to gently press the center bi-metal and
pin. The control pressure should increase. If not, the restriction plate restriction hole,
which is .0045-inch (0.11 mm) diameter, may be clogged.
5. Remove the two screws and holding cover.
6. Remove the gaskets and restriction plate.
7. Clean the restriction hole with compressed air.
8. Replace the gasket, restriction plate, rubber gasket and cover.
9. Tighten screws.
1. Test both the day and night supply pressures, since either nozzle could be clogged.
2. Use a flat-blade screwdriver to gently push the center leg of the bi-metal away from
the throttling pin.
3. If the control pressure does not drop to approximately 1/2 psi, check for a clogged
nozzle or a sticking throttling pin.
NOTE: Replacement parts are no longer available for these models. If this problem
persists, replace the unit with a TH-192 Thermostat.
1. Use either the 18 psi or 25 psi (124.0 kPa or 172.2 kPa) air supply.
4. If the control pressure does not drop to 1/2 psi (3.4 kPa) when the bi-metal is pulled
away from the throttling pin, then there is dirt on the throttling pin or brass exhaust
valve seat.
5. This dirt particle can usually be removed by moving the pin with a flat-blade
screwdriver so that it alternately opens and closes the nozzle. This fluttering action
will usually dislodge dirt from the throttling pin or brass exhaust valve seat.
NOTE: Replacement parts are no longer available for this model. If this problem
persists, replace the unit with a TH-192 Thermostat.
Technical Bulletin
Document Number 155-253P25
December 9, 2003
Page 11