Modine Manufacturing PV Installation And Service Manual page 24

S S E E R R V V I I C C E E I I N N S S T T R R U U C C T T I I O O N N S S – – S S A A F F E E T T Y Y D D E E V V I I C C E E S S – – C C O O M M P P O O N N E E N N T T I I D D E E N N T T I I F F I I C C A A T T I I O O N N
F F i i g g u u r r e e 1 1 3 3
S S e e r r v v i i c c e e , , S S a a f f e e t t y y a a n n d d O O t t h h e e r r M M a a j j o o r r U U n n i i t t H H e e a a t t e e r r C C o o m m p p o o n n e e n n t t s s
ROTATABLE POWER
EXHAUSTER
VENT PIPE
CONNECTION
FAN
MOTOR
FAN
GUARD
IGNITION
CONTROL
COMBINATION
GAS CONTROL
PRESSURE SWITCH
L L i i m m i i t t C C o o n n t t r r o o l l ( ( O O v v e e r r h h e e a a t t S S w w i i t t c c h h ) )
The limit control, mounted on the left inner side panel (when
facing front of unit), will shut off the gas supply to the main
burner in the event of overheating. It is a single pole, single
throw switch. The contacts open to shut the electric gas valve
off in the event the unit should overheat. This limit control
should operate only when something is seriously wrong with the
unit. Anytime this control operates, correct the difficulty
immediately or serious damage may result. If the limit control
cuts off the gas supply during normal operation:
1. Make certain the deflector blades are open and that there
are not any obstructions in the air inlet or discharge outlet.
2. Check actual input to unit against rated input.
3. Check to be sure motor is operating.
4. On propeller units, check that fan is not loose on motor
shaft. On blower units, check belt and sheave for tightness
or damage.
5. On propeller units, check fan speed against speed on motor
nameplate. On blower units, check blower speed against
Performance Data on pages 16 or 17, check for restriction in
ducts and for dirty filters.
2 2 4 4
PRESSURE
SENSING TUBE
HEAT
EXCHANGER
LIMIT CONTROL LOCATED
UNDER LEFT-SIDE PANEL
FOR SERVICE REMOVE
LEFT-SIDE PANEL
TERMINAL
BOARD
JUNCTION
BOX
6. Check to make sure the venting system is not damaged or
blocked. Also check to be sure unit is venting normally and
that there is not negative pressure in the building adversely
affecting draft.
7. Clean heat exchanger tubes inside and out if necessary.
8. If items 1-7 do not solve the problem, check limit control and
replace if necessary. The control is accessible by removing
the left outer side panel, held in place by screws at the rear
of the unit.
I I M M P P O O R R T T A A N N T T N N O O T T E E : :
T T h h e e l l i i m m i i t t c c o o n n t t r r o o l l ( ( o o v v e e r r h h e e a a t t s s w w i i t t c c h h ) ) o o n n t t h h i i s s u u n n i i t t h h e e a a t t e e r r w w i i l l l l s s h h u u t t
o o f f f f t t h h e e g g a a s s s s h h o o u u l l d d e e x x c c e e s s s s i i v v e e d d i i s s c c h h a a r r g g e e t t e e m m p p e e r r a a t t u u r r e e s s o o c c c c u u r r . . D D o o
n n o o t t a a t t t t e e m m p p t t t t o o c c o o n n t t r r o o l l t t h h e e f f a a n n w w i i t t h h t t h h e e l l i i m m i i t t c c o o n n t t r r o o l l . . A A n n y y c c h h a a n n g g e e
i i n n w w i i r r i i n n g g t t o o a a t t t t e e m m p p t t t t o o c c o o n n t t r r o o l l t t h h e e f f a a n n w w i i t t h h t t h h e e l l i i m m i i t t c c o o n n t t r r o o l l w w i i l l l l
r r e e s s u u l l t t i i n n h h a a z z a a r r d d o o u u s s c c o o n n d d i i t t i i o o n n s s a a n n d d v v o o i i d d t t h h e e w w a a r r r r a a n n t t y y . .
LEVEL HANGING ADJUSTMENT
BRACKETS & SLOTS
LOUVER
BLADES
COMBUSTION AIR INLETS & BURNER