Mighty Therm Lo-Nox
Page 9
Figure 8 is suggested to make sure the system water is
neither too hot nor too cold when a changeover takes
place. When a boiler is connected to heating coils
located in air handling units (where they may be
exposed to refrigerated air circulation), install a flow
Figure 9. Primary-Secondary Plumbing.
Boiler Circulation
Pump
Cold Water
Make-Up
System Pump
12"
Max.
12"
Max.
12"
Max.
12"
Max.
Thermometer
Temperature
Sensor
Globe Valve
Check Valve
Pressure Reducing Valve
w/Fast Fill Bypass
Expansion Tank
with Air Scoop and
Auto Air Vent
3-Way Valve
Valve
Pump
LEGEND:
Boiler circuit piping must be equal to or larger
than boiler water connection size.
Boiler circulation pump sized for flow through
boiler.
Dotted devices indicate alternate locations.
WARNING: This drawing shows suggested
piping configuration and valving. Check with
local codes and ordinances for additional
requirements.
Purge
Valve
3-Way Valve No. 1
Change-Over
(Heating and Cooling)
3-Way Valve No. 2
To By-Pass
Both Heater and
Chiller
To
System
From
System
By-Pass
To Boiler
and
Chiller
From
Boiler
Valve Motors
2-Pos
3-Wire - 24V
115/24V
Transformer
DPDT Manual or Automatic
Change-Over Switch
DPDT - Set at Change-Over
Temperature
Clock Timer
Auto-Resetting
Set at 15 Minute SPDT
Suggested Wiring Diagram For
Tempering System Water at
Changeover From Heating To Cooling
Figure 8. Boiler-Chiller Installation.
From
Chiller
control valve or other automatic means to prevent
gravity circulation of chilled water through the boiler.
Chilled water in the boiler will create condensate on
the boiler tubes. Boilers installed in violation of the
foregoing may void the warranty.
3.2.4 Combined Space Heating/Potable
Water Heating Systems
When using the Laars boiler as a source of heat
for a combined space heating/potable water heating
system, be sure to follow the instructions of the space
heating system.
Do not use water piping, fittings, valves, pumps,
and any other components which are not compatible
with potable water.
Do not connect the heater, which will be used to
supply potable water, to any heating system or
components previously used with a nonpotable water
heating system.
Do not add boiler treatment or any chemicals to
the heating system piping, since the piping contains
water for potable use.
Do not use solder containing lead in the potable
water lines.
Some jurisdictions may require a backflow
preventer in the cold water line. In such cases,
pressure relief valve may discharge water due to
expansion. An expansion tank approved for potable
water will eliminate this condition. Follow the
manufacturer's instructions for installation of the
expansion tank.
