Thermo Products COMBOMAX Models from 8 kW to 24 kW : 240 Volts ( single phase ) - Manual (Page 10)

COMBOMAX MC Electric boiler Set-up, use and care guide (revised January 2006) , Page 10.
Section 4 : Operation
Before operating this water heater, be sure to
read and follow these instructions, as well as
the warnings printed in this manual. Failure
to do so can result in unsafe operation of the
water heater resulting in property damage,
bodily injury, or death. Should you have any
problems reading, following or difficulty in
understanding the instructions in this
manual, STOP, and get help from a qualified
person.
Do not turn on the water heater unless it is
filled with water. Do not turn on water heater
if cold water supply shut-off valve is closed.
Once the plumbing and electrical connections
are completed, your COMBOMAX
MC unit is
ready for automatic operation.
4.1 FILLING THE TANK
Open the outlet valve (in a zone valve system,
manually open the zone valves).
Open the boiler inlet valve. Bleed the air from
the boiler tank by opening the safety valve atop
the boiler while you are filling the tank.
Leave all valves open. Reset the zone valves to
automatic operation. Check for leaks and repair
if necessary.
Bleed the air from all zones if required. Check
the boiler pressure gauge. A pressure reading
between 15 and 20 psi is normal for most
installations.
4.2 FILLING THE HEATING COIL
Make sure all drain cocks are closed.
Open the nearest domestic hot water tap as well
as any control valve on the water heater outlet
(the copper tube atop the boiler).
Open the cold water inlet valve on the heater
inlet tube. (the copper tube on the left side of the
unit).
Close the domestic hot water tap as soon as
water flows out of it. Fix any leaks
Open all other hot water taps fed by this heating
coil to bleed the air trapped behind them.
4.3 ADJUSTING THE AQUASTATS
Once all air has been bled from the system and
all components (valves, bleeders, controls) have
been properly adjusted, the boiler can be put
into operation. Never operate the boiler before
these adjustments are complete.
Bear in mind safety and energy-saving
considerations when adjusting the boiler water
temperature with the aquastats. It is most
energy-efficient to set them as low as possible,
in a manner consistent with your heating needs.
However, a minimum temperature of 160°F is
recommended for domestic hot water
production.
Each aquastat controls a boiler stage (in the
240V model, each element has its own
aquastat). Adjust the setting of each aquastat by
turning the dial scaled in degrees Celsius and
Fahrenheit. See figure 10 for aquastat
identification.
Set the first aquastat to the highest outlet
temperature required by the heating system.
Thermo 2000 inc. recommends a setting of
180°F.
Adjust the second aquastat 1°F to 20°F below
the first aquastat setting. Usually, a setting 5°F
below that of the first aquastat, or 175°F,
provides good results in a system designed for a
20°F temperature drop between the tank inlet
and outlet.
Proceed in a similar manner for the 3rd and 4th
aquastats, which will result in settings of 170°F
and 165°F. Thus, the number of elements in
operation will increase (or decrease) according
to the settings and the drop (or rise) in the
heating water temperature.
The domestic hot water priority aquastat should
be adjusted to a setting 5
o
F below that of the last
stage or 4
th
aquastat, i.e., 160°F.
At system start-up (on the first heating day of the
season), ìt may take quite some time for the
boiler water to reach its operating temperature.
Check the thermo manometer.
SAFETY PRECAUTIONS !