Mini-Combo
id
Page 5
persons. Attach run-off tube to T&P valve and
run tube within 6" (152mm) from floor. No
reducing couplings, valves, or any other type of
restriction is to be installed in this line. This run-
off tube must be installed to allow free and
complete drainage of both valve and run-off tube.
•
Filling Storage Water Tank
1.
Open hot water faucet in house to allow air
in the tank and in piping to escape.
2.
Open shut-off valve(s) in cold water supply
line.
3.
Open shut-off valve(s) in hot water supply
line.
2B. Heater Placement
The heater must be placed to provide clearances
on all sides for maintenance and inspection. Allow 4
inches on each side for piping access. There must also
be minimum distances maintained from combustible
surfaces. Figure 1 shows minimum clearance from
combustible surfaces. The Mini-Combo unit can be
installed in a closet, as long as the minimum
clearances are maintained. Special attention should be
paid to the air supply opening to the closet. Refer to
Table 1.
Figure 5. MCH Schematic.
Net Free Area — square inches
sq. cm
Model
Inside Air
Outside Air
MC50
100
645
15
97
MC75
100
645
20
129
MC100
100
645
25
161
MC125
125
806
32
206
Area indicated is for one of two openings: One at floor level and
one at the ceiling, so the total free area would be double the
figures indicated. Refer to Document 1080 for more information.
Table 1. Minimum Recommended Air Supply.
2C. Piping
• To prevent damage to the unit, all soldering is to
be done prior to assembling the cold and hot
water, and any other connections to the tank.
• Use suitable pipe dope or tape.
• Before piping the boiler to the heating system,
be sure to install the system check valve
(provided with the unit) onto the inlet (return)
tee of the boiler with arrow pointed downward
(see Figure 3).
• If anti-freeze is used in boiler system, local codes
may require a backflow preventer on cold supply
line. Use anti-freeze specifically intended for
hydronic heating system. Inhibited propylene
glycol is recommended.
WARNING
Do not use automotive or ethylene glycol anti-
freeze, or any undiluted anti-freeze. This can
cause severe personal injury, death or substantial
property damage.
If a backflow preventer, pressure reducing valve
or check valve is in cold water supply, install an
expansion tank on cold water supply line (see
Figure 4) to prevent normal thermal expansion from
repeatedly forcing open the T&P relief valve.
•
T&P relief valve's discharge piping must be
directed so that hot water flows away from all
