Install Instructions

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9. Place the panel between side panels upper inside
anges and slide it forward, until top panel front
ange U-bend locks over front panel top ange, and,
top panel rear ange is positioned over rear jacket
panel.
10. Locate/remove two #8 x ½” sheet metal screws from
Hardware Bag.
11. Install both screws into top panel rear ange to
secure the top panel to rear jacket panel.
K. EXTERNAL ELECTRICAL ENCLOSURE
MOUNTING.
1. Remove two #8 x ½” shoulder sheet metal screws
and one #8 x ½” sheet metal screw from Hardware
Bag.
2. Install both #8 x ½” shoulder sheet metal screws
into Right Side Jacket Panel, at two upper corners of
the panel front cutout.
3. Locate and remove External Electrical Enclosure
assembly from Control Carton.
4. Remove the enclosure cover and set aside.
5. Pick Molex connector end of Burner Harness and
feed it inside the enclosure, thru bushed hole at
enclosure lower left corner, next to transformer/
relay.
6. Place the enclosure over installed shoulder sheet
metal screws, so teardrop cutouts in the enclosure
base engage both screws simultaneously, then, slide
the enclosure downwards to lock it in place.
7. Install #8 x ½” sheet metal screw thru enclosure
base lower hole, located to the right of transformer/
relay, into right side panel to secure the enclosure.
8. Plug-in burner harness Molex connector into
dedicated burner harness receptacle inside the
enclosure (lower left off transformer/relay). See “
Control Plug-In Diagram” label attached to inside of
the enclosure cover for details.
9. Do not install the enclosure cover yet; proceed to
control installation.
L. TRIM AND CONTROLS INSTALLATION.
Pressure Limit Installation.
1. Locate and remove L404F Pressure Limit with
factory attached harness from Control Carton.
2. Locate and remove 1/4" NPT x 1-7/8" x 4 x 90°
syphon enclosed in Part Carton.
3. Review and locate pressure limit tapping on front
section. See Table 3 “ Purpose of Tappings &
Bosses” and Figure 7.
4. Thread 1-7/8" lg. syphon-threaded short end into
the bottom of Pressure Limit with factory attached
Figure 8: Pressure Limit Installation
harness. Do not tighten the syphon by holding the
limit case; apply a wrench to the brass hex below
the case.
5. Thread ¼" NPT x 4" lg. syphon-threaded long end
into pressure limit tapping on front section. See
Figure 8 "Pressure Limit Installation.
6. L404F pressure limit does not require leveling. The
pressure limit nal orientation must be parallel to
boiler front, having the harness on the right side.
7. Pick-up the pressure limit harness Molex end and
feed it into the enclosure, thru top ange rear left
7/8” hole; then, snap-in harness BX connector into
the hole, and, plug Molex connector into dedicated
pressure limit receptacle inside the enclosure (upper
left off transformer/relay). See “ Control Plug-In
Diagram” label attached to inside of the enclosure
cover for details.
SECTION II: UNIT-PAK BOILER ASSEMBLY (continued)
M. PROBE LWCO (HYDROLEVEL CG450,
OR, MCDONNELL-MILLER PS801-120)
INSTALLATION.
1. Remove either Hydrolevel CG450 LWCO with
factory attached harness and Hydrolevel probe
#EL1214, or, McDonnell-Miller PS801-120 with
factory attached harness and #153875 probe from
Control Carton.
2. Install the probe into the appropriate front section
tapping. See Figure 7 “Purpose of Tappings &
Bosses”.
3. Slip LWCO with factory attached harness over the
probe and clamp in place. Note that CG450 LWCO
will be positioned right side up, with diagnostic
LED(s) on the top ange, while PS801 LWCO
will be positioned upside down, with diagnostic
LED(s) on the bottom ange. Connect the wire(s)
between the probe and control per manufacturer’s
instructions.