Siemens Powers TH 192 S Technical Instructions page 10

Technical Instruction
Document No. 155-065P25
Rev. 1, July, 1999
C C C C h h h h a a a a ss ss ss ssi i i i s s s s T T T T ub ub ub ube e e e
C C C C o o o o nn nne e e e c c c c t t t t o o o o r r r r a a a a nd nd
nn nn nd nd
R R R R es est t t t r r r r i i i i c c c c t t t t o o o o r r r r P P P P l l l l a a a a t t t t e e e e
es es
R R R R e e e e p p p p l l l l a a a a c c c c e e e e m m m m e e e e n n n n t t t t
Page 10
P P P P r r r r o o o o b b b b l l l l e e e e m m m m
Control pressure
stays at
Nozzle or flapper
approximately zero
Control pressure
stays at
approximately
supply pressure
Excessive air Supply and return
leakage from line connection
exhaust port on
left side of
thermostat
1. Remove thermostat chassis from wall. Terminal does not have a ball check valve.
N N N N O O O O T T T T E E E E : : : : You must close off the supply air. For example, use a connector with the
supply air terminal plugged.
2. Remove two Phillips head screws from connector on back of thermostat chassis.
Pull connector out of recess. If necessary, pry connector loose with a screw driver,
but be careful not to damage restrictor plate and gasket.
3. Remove gasket from under connector. Remove restrictor. Remove second gasket
from under restrictor.
4. Use restrictor replacement kit 192-321 to replace gasket, restrictor, and second
gasket.
N N N N O O O O T T T T E E E E : : : : The restrictor plate is keyed to ensure proper orientation during installation.
5. Remove filters from existing connector and insert in new connector. Or, if filters are
dirty, use restrictor replacement kit 192-321 to replace filters.
6. Use chassis tube connector replacement kit 192-525 to replace connector and
mounting screws.
T T T T a a a a b b b b l l l l e e e e 4 4 4 4 . . . . T T T T r r r r o o o o u u u u b b b b l l l l e e e e s s s s h h h h o o o o o o o o t t t t i i i i n n n n g g g g G G G G u u u u i i i i d d d d e e e e . . . .
C C C C he hec c c c k k k k he he
Air supply Low supply pressure
Dirt on nozzle or
flapper
Restrictor Clogged restrictor
Calibration Out of calibration
Nozzle Clogged nozzle
Calibration Dirt on either supply
or exhaust valve seat
Connections are
interchanged or
connection to port is
incorrect
C C C C a a a a u u u u s s s s e e e e A A A A c c c c t t t t i i i i o o o o n n n n
As required
Clean nozzle or replace
thermostat
Replace restrictor
Recalibrate
Clean nozzle or replace
thermostat
Alternately close and
open nozzle by gently
pushing down the
bimetal
As required
Siemens Building Technologies, Inc.
Landis Division