Modine Manufacturing DJE Installation And Service Manual page 19

S S E E R R V V I I C C E E I I N N S S T T A A L L L L A A T T I I O O N N S S
F F i i g g u u r r e e 1 1 4 4 – – B B V V S S S S T T r r o o u u b b l l e e s s h h o o o o t t i i n n g g F F l l o o w w C C h h a a r r t t
Is there a negative pressure in building? (see note 2)
YES
Can negative pressure
be corrected?
YES NO
Correct Install
negative power vent
pressure accessory
Note 1: To determine spillage, place lit match
stick (6" - 8" match stick if possible) 2" - 3"
into diverter relief opening and determine
direction of the flame (or direction of
smoke if flame goes out). If flame or
smoke comes back at you, there is
spillage. The flame or smoke should be
pulled in.
Note 2: One indication of negative pressure is
that outside doors tend to swing toward
inside of building.
G G e e n n e e r r a a l l M M a a i i n n t t e e n n a a n n c c e e
1. Service air moving components annually.
On duct blowers, this should include:
(1) Checking motor and blower bearings for lubrication.
(2) Checking belts and pulleys for proper alignment and
adjustment.
(3) Checking cleanliness of blower wheel and filters.
2. Keep unit free from dust, dirt, grease, and foreign matter,
paying particular attention to:
a. Secondary air intake slots.
b. Burner ports, pilot burner, and main burner orifices
(avoid use of hard, sharp instruments capable of
Is vent blocked or restricted?
YES
Remove restriction
NO
Is vent in compliance
with NFGC?
YES
YES
Reduce input
NO
Is there spillage after 5 minutes? (see note 1)
YES
NO
Correct vent
Is unit overfired?
Can one or more of the following be done?
• Lengthen vertical vent run
• Insulate vent
• Use larger diameter vent
• Use less restrictive weather cap
YES
Does unit still trip?
YES
Install power vent
OK
accessory
damaging surfaces, for cleaning these ports.) If an air
pressure system is available it can be used to blow
dirt and other foreign matter from within the burner.
Also main burner orifices should be checked for
blockage due to spider webs, etc.
c. Primary air shutters.
d. Heat exchanger tubes (clean from bottom with wire
brush after removing burner box assembly).
3. Check wiring for possible loose connections.
4. Controls - See control instruction sheets furnished
separately with unit.
NO
Replace blocked vent switch;
Does switch still trip?
YES
NO
NO
Install power vent
accessory
NO
NO
OK
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