Servicing - Modine Manufacturing PDE Installation And Service Manual

4 4 . . S S E E R R V V I I C C I I N N G G
It is recommended that a full service be carried out at least
once a year by a qualified heating engineer (CORGI
Registered).
CAUTION
!
Always turn off the gas supply at the gas cock and
disconnect the electricity supply to the appliance before
servicing or replacing any components.
4 4 . . 1 1 C C l l e e a a n n i i n n g g t t h h e e H H e e a a t t e e r r
4 4 . . 1 1 . . 1 1 M M a a i i n n B B u u r r n n e e r r
Lower bottom pan by removing wing screws on the unit base.
Disconnect pilot pipe, and thermocouple lead from multifunctional
control.
Remove the two burner retaining pins holding the burner
assembly in place.
I I M M P P O O R R T T A A N N T T : : 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 r r e e m m o o v v e e t t h h e e g g a a s s m m a a n n i i f f o o l l d d t t o o
e e a a s s e e r r e e m m o o v v a a l l o o f f t t h h e e b b u u r r n n e e r r a a s s t t h h i i s s c c o o u u l l d d s s e e r r i i o o u u s s l l y y a a f f f f e e c c t t t t h h e e
c c o o r r r r e e c c t t o o p p e e r r a a t t i i o o n n o o f f t t h h e e a a p p p p l l i i a a n n c c e e i i f f i i t t i i s s n n o o t t r r e e -p p o o s s i i t t i i o o n n e e d d e e x x a a c c t t l l y y
a a s s i i n n t t e e n n d d e e d d . . T T h h e e a a s s s s e e m m b b l l y y c c a a n n n n o o w w b b e e l l o o w w e e r r e e d d f f r r o o m m t t h h e e u u n n i i t t . .
N N O O T T E E : : O O n n r r e e f f i i t t t t i i n n g g t t h h e e b b u u r r n n e e r r a a s s s s e e m m b b l l y y e e n n s s u u r r e e t t h h a a t t t t h h e e s s l l o o t t s s a a t t
t t h h e e f f r r o o n n t t o o f f t t h h e e b b u u r r n n e e r r a a r r e e c c o o r r r r e e c c t t l l y y l l o o c c a a t t e e d d o o n n t t h h e e i i r r s s h h o o u u l l d d e e r r
r r i i v v e e t t s s a a n n d d t t h h a a t t t t h h e e r r e e t t a a i i n n i i n n g g p p i i n n s s a a r r e e r r e e f f i i t t t t e e d d i i n n t t h h e e c c o o r r r r e e c c t t
l l o o c c a a t t i i o o n n . .
Clean the burner ports (avoid using hard, sharp instruments
capable of damaging the ports) and check the injector (s) for
blockage. Clean carefully as necessary.
4 4 . . 1 1 . . 2 2 P P i i l l o o t t B B u u r r n n e e r r
Inspect the pilot burner and thermocouple. Ensure they are clean
and in good condition.
C C h h e e c c k k : :
(a) The pilot burner is securely fixed.
(b) The thermocouple tip is not burned or cracked. Replace if
necessary.
(c) The pilot burner head is undamaged.
(d) The pilot pipe/pilot connection is gastight.
4 4 . . 1 1 . . 3 3 H H e e a a t t E E x x c c h h a a n n g g e e r r
After removing the burner assembly clean heat exchanger tubes
from bottom using a stiff brush ( ( n n o o t t w w i i r r e e ) ) .
4 4 . . 1 1 . . 4 4 F F a a n n a a n n d d M M o o t t o o r r
Remove fan guard. Check fan is securely fitted to motor shaft
and for damage to blades. Clean fan blades as necessary taking
care not to damage them.
N N O O T T E E : : E E n n s s u u r r e e a a l l l l f f o o u u r r f f i i x x i i n n g g s s s s l l e e e e v v e e s s a a r r e e f f i i t t t t e e d d b b e e f f o o r r e e r r e e -f f i i x x i i n n g g
f f a a n n a a s s o o v v e e r r t t i i g g h h t t e e n n i i n n g g c c o o u u l l d d r r e e s s u u l l t t i i n n r r e e d d u u c c e e d d f f a a n n l l i i f f e e . .
4 4 . . 1 1 . . 5 5 G G e e n n e e r r a a l l
Check wiring for possible loose connections paying particular
attention to the overheat thermostat interrupter leads.
Check air louvres in bottom pan are clean and unobstructed.
Clean as necessary.
4 4 . . 2 2 O O v v e e r r h h e e a a t t T T h h e e r r m m o o s s t t a a t t
The overheat thermostat, bulb mounted on the left inner side
panel (when facing front of unit) – body in junction box, will shut
off the gas supply to the main burner in the event of overheating.
The manual reset button is located beneath a black screw off cap
positioned on the side of the junction box. See Figs. 6 and 7.
8 8
It is a single pole single throw switch. The contacts open to shut
the combination gas control in the event of the unit overheating.
This overheat thermostat should operate only when something is
wrong with the unit. Whenever this thermostat operates, the
problem should be identified and corrected immediately or
serious damage may result. If the overheat thermostat cuts off
the gas supply during normal operation:
1. Make sure 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 motor is operating.
4. Check fan is not loose on motor shaft.
5. Check fan speed against motor data plate.
6. Check flue system is not damaged or blocked. Also check
unit is flued correctly and that there is not a negative
pressure in the building adversely affecting draught.
7. Clean heat exchanger tubes inside and out if necessary.
8. Check operation of fan delay timer.
9. If items 1 to 8 do not solve the problem, check overheat
thermostat and replace if necessary.
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 o o v v e e r r h h e e a a t t t t h h e e r r m m o o s s t t a a t t 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
o o v v e e r r h h e e a a t t t t h h e e r r m m o o s s t t a a t t . . 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 o o v v e e r r h h e e a a t t t t h h e e r r m m o o s s t t a a t t 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 i i n n v v a a l l i i d d a a t t e e t t h h e e w w a a r r r r a a n n t t y y . .
4 4 . . 3 3 T T e e s s t t i i n n g g a a f f t t e e r r S S e e r r v v i i c c i i n n g g
After re-assembly restore the electrical and gas supplies. Light
the appliance (see Lighting Instructions on inside of casing) and
check the gas connections for soundness as follows:
Close gas supply cock at the meter.
Remove the screw in the inlet pressure test point and connect a
manometer to the test nipple. Open the gas supply cock at the
meter and the appliance gas cock. Record the static pressure.
Close the gas supply cock at the meter and watch the pressure
gauge for approximately 3 minutes. Any decrease in pressure
(after the first minute of temperature stabilization) indicates a
gas leak which must be cured (first check connection of
manometer to test nipple). When satisfied remove manometer
and refit test nipple sealing screw.