Burnham MEGASTEAM MST288 - Manual (Page 18)

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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
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 final 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 flange 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.
Figure 8: Pressure Limit Installation
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 flange, while PS801 LWCO
will be positioned upside down, with diagnostic
LED(s) on the bottom flange. Connect the wire(s)
between the probe and control per manufacturer’s
instructions.
4. Pick-up the LWCO harness Molex end and feed it
into the enclosure, thru external electrical enclosure
top flange front left 7/8” hole; then, snap-in harness
BX connector into the hole, and, plug-in Molex
connector into dedicated LWCO receptacle inside
the enclosure (middle left off transformer/relay). See
“ Control Plug-In Diagram” label attached to inside
of the enclosure cover for details.
N. PRESSURE GAUGE AND GAUGE GLASS
INSTALLATION.
1. Remove the 6” water gauge glass set from Part
Carton.
2. Install the gauge glass using the two ½” NPT
tappings to the right of the probe LWCO. See Figure
7 “Purpose of Tappings & Bosses”.
3. Thread the pressure gauge into 1/4” NPT tapping of
the front section. See Figure 7 “Purpose of Tappings
& Bosses”. Tighten with wrench applied to the
square shank of the gauge.
CAUTION
Do not apply pressure to gauge case, as this may
result in inaccurate readings.
O. FLOAT LwCO (MCDONNELL-MILLER #67),
AND GAUGE GLASS INSTALLATION.
1. Pre-assemble float-type LWCO per Figure 9 "Float-
Type LWCO and Gauge Glass Installation".
2. Install two ½” NPT x 2½" long Sch 40 brass nipples,
supplied loose inside Control Carton (disregard two
½" NPT x 1½" long brass nipples provided with
#67 LWCO package) and ½" NPT brass unions into
upper and lower front section tappings. See Table 3
"Purpose of Tappings & Bosses" and Figure 7.
3. Install water gauge glass on low water cut-off
assembly tee fittings.
4. Do not remove ¼” NPT plug factory installed on top
of #67 LWCO.
5. Insure that 3/8" NPT plug (provided within #67
LWCO package) is installed at bottom of #67
LWCO.
6. Remove #67 LWCO J-box cover.