Thermo Products COMBOMAX Models from 8 kW to 24 kW : 240 Volts ( single phase ) - Manual (Page 11)

COMBOMAX MC Electric boiler Set-up, use and care guide (revised January 2006) , Page 11.
Adjust the boiler aquastats as required. Please
note that lowering the setting will not have an
immediate effect as the heat stored in the boiler
water must first be consumed. Check the boiler
water temperature periodically. Further
adjustments may be required as the system
goes through several space and water heating
cycles.
Note: The maximum setting for the boiler outlet
temperature is 190°F.
4.4 STARTUP PROCEDURE
1. Fill tank and coil as described in
sections 4.1 and 4.2.
2. Adjust temperature levels as described
in section 4.3
3. Set domestic thermostat level(s) below
room temperature.
4. Activate boiler breakers.
5. The main boiler contact should close
and all elements should turn on, along
with their pilot lights.
6. The circulator should start up and the 3-
way valve should switch to the A side.
7. Boiler temperature should rise.
8. Circulator stops and the 3-way valve
switches to the B side when boiler
temperature exceeds the setting of the
domestic hot water priority aquastat.
9. Boiler temperature rises and the
elements and corresponding pilot lights
turn off one after the other as their
temperature setting is reached.
10. When all elements are off, increase the
setting of the domestic thermostat(s) to
a point above room temperature.
11. Circulator should start up following a
delay period.
12. Heating elements should turn back on
as their temperature setting is reached;
this could take a few minutes.
13. Circulator runs as long as a demand
exists for heating. When circulator turns
off …
14. Boiler temperature rises. Heating
elements and corresponding pilot lights
should turn off as their temperature
setting is reached.
Thus, boiler power requirements depend on
heating demand within the building. If only one
heating element is required to satisfy the
demand, only one is activated ; if two are
required, two are activated, etc ... You thus
avoid excessive wear and tear on the
components due to numerous on-off cycles and
reduce your total heating costs.
4.5 DOMESTIC HOT WATER STARTUP
Maximum boiler water temperature is 190°F.
This should be 20°F to 40°F above the desired
temperature for domestic hot water. In practice,
the boiler water temperature should be between
160°F and 180°F.
An excessively high setting can cause
scalding. Use the thermostatically controlled
mixing valve included with the unit to lower
the domestic hot water temperature and thus
the risk of injury.
When the boiler water temperature falls below
the setting of the domestic hot water priority
aquastat, the 3-way valve switches to side A and
the circulator starts up.
When the boiler water temperature reaches the
setting of the domestic hot water priority
aquastat, the 3-way valve returns to side B
unless other zones are calling for heat. The
heating elements remain on until they reach
their set points. It is normal to observe the boiler
cycling on and off close to the highest set point,
particularly if a single zone is calling for heat.
Considerable time may elapse from a cold start
to the moment when the highest set point is
reached. Check the domestic hot water
temperature as soon as the first heating cycle is
complete.
Lowering the set points has no immediate effect.
The boiler water heat must first be transferred to
the coil. Additional checks will be necessary at
the end of successive heating cycles. Further
adjustments may be required as time goes by.
The domestic hot water priority aquastat is set at
its minimum at shipping time. It can be
increased to 190°F for commercial use.
Remember that domestic hot water hotter than
125°F can cause scalds. Use this minimum
setting as a starting point for any further
adjustments. Normally, the domestic hot
water priority aquastat is set to 5°F below the
lowest heating element aquastat set point.
DANGER !