Modine Manufacturing DJE, Installation And Service Manual

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4 4
IIN NS ST TA AL LL LA AT TIIO ON N
A Aiirr F Fllo ow w S Se ec cttiio on n
An air distribution baffle is provided on all Modine duct
furnaces. This baffle must be in place if the air temperature
rise through the duct furnace is 55°F or greater. When the air
baffle is required it must always be on the air inlet side of the
duct furnace. (See Figures 2 and 3.)
A limit control (overheat switch) is also provided on all Modine
duct furnaces. The sensing bulb of the limit control must
always be in place and must always be on the discharge air
side of the duct furnace. (See Figures 2 and 3.)
Before installing duct furnace, determine the desired direction
of the air flow through the duct furnace. If the installation is
such that the desired air flow direction through the duct
furnace is opposite of the direction required as the unit is
shipped, the position of the air distribution baffle and limit
control sensing bulb must be reversed. To make this change,
do the following:
Select proper direction of air flow. T Th he e d diis sttrriib bu uttiio on n b ba afffflle e (if it is
used) m mu us stt ffa ac ce e tth he e iin nlle ett d diirre ec cttiio on n.. The baffle may be changed
to the opposite side, if the air flow direction is changed
(Figures 2 and 3). W
Wh he en n rre ev ve errs siin ng g a aiirr ffllo ow w tth he e tte em mp pe erra attu urre e
s se en ns siin ng g b bu ullb b b be ettw we ee en n tth he e h he ea att e ex xc ch ha an ng ge err ttu ub be es s m mu us stt b be e
rre ev ve errs se ed d tto o tth he e a aiirr o ou uttlle ett s siid de e.. The sensing bulb must not
touch sides of heat exchanger tubes (Figures 3 and 13). To
change position of limit control sensing bulb, remove sensing
bulb from clips on support bracket. (Note position of bulb
relative to mounting bracket.) Thread capillary tube and
sensing element back through access hole in bottom header
of heat exchanger. Remove rubber grommet in bottom header
of heat exchanger. Capillary tube has a liquid center, do not
crimp tube or put sharp bends in tube. Bring sensing bulb and
furnace capillary tube around the outside of the duct furnace,
to the opposite side, and up through the access hole in bottom
header. Replace rubber grommet. Mount sensing element in
retaining clip on discharge end of duct furnace, locating the
bulb in the same relative position as it was in its original
location. Place capillary tube in remaining retaining clips. Be
certain that neither the sensing bulb nor the capillary tube
come in direct contact with the heat exchanger. The exposed
capillary tube should be protected from damage due to cuts,
blows or wear from vibration.
F Fiig gu urre e 2 2 -- A Aiirr F Fllo ow w
F Fiig gu urre e 3 3 -- U Un niitt C Cu utta aw wa ay y
IIn ns stta alllla attiio on n iin n D Du uc ctt
Insufficient air, or poor air distribution across the duct furnace
heat exchanger will cause early failure of the duct furnace.
When installing duct furnaces, always follow good duct design
practices for even distribution of the air across the duct
furnace heat exchanger. Recommended layouts are shown in
Figure 4, as well as designs that are to be avoided. When
installing duct furnaces the following must be done.
1. Provide air tight seal between ductwork and furnace.
Seams with cracks in ductwork should be caulked and/or
taped and be of permanent type. All duct connections
MUST be air tight to prevent air-leakage that will disturb the
flame. A duct system is generally under pressure and even
a small leak can cause flame disturbance and/or pilot
outage problems. D
Do o n no ott b bllo oc ck k d drra afftt d diiv ve errtte err o op pe en niin ng g o orr
e en nc cllo os se e d diiv ve errtte err o op pe en niin ng g iin n d du uc cttw wo orrk k..
2. P Prro ov viid de e u un niiffo orrm m a aiirr d diis sttrriib bu uttiio on n o ov ve err tth he e h he ea att e ex x--c ch ha an ng ge err..
Use turning vanes where required (see Figure 4) to obtain
uniform air distribution. Avoid installing as in G, H & J of
Figure 4.
CAUTION
Air distribution baffle shipped with duct furnace, if required,
must always be on the air inlet side of the duct furnace. The
sensing bulb of the limit control (overheat switch) must
always be on the discharge air side of the duct furnace.
!
DRAFT DIVERTER
MOUNTING HOLES (4)
ALUMINIZED STEEL
HEAT EXCHANGER
AIR DISTRIBUTI0N
BAFFLE (ON INLET
AIR SIDE)
LIMIT CONTROL
CAPILLARY TUBE
RUBBER GROMMET
LIMIT CONTROL
PRIMARY
AIR CONTROL
MANIFOLD
COMBINATION
GAS CONTROL
SERIAL PLATE,
LIGHTING INSTRUCTION
(LOCATED ON
SIDE PANEL)
DRAIN PAN
BURNER ASSEMBLY
BURNER
ACCESS
PANEL
LIMIT
CONTROL
SENSING BULB
(ON DISCHARGE
AIR SIDE)
ALUMINIZED
STEEL CASING
CAUTION
Proper air flow and distribution, across the duct furnace
heat exchanger must be provided to prevent early failure of
the duct furnace.
!
CAUTION
Check for red heat exchanger tubes. If bottom of tubes
becomes red while blower and duct furnace are in
operation, additional baffles must be inserted between
blower and duct furnace, as shown in Figure 4, to assure
uniform air flow across the heat exchanger.
!