LAARS EDN Series - Installation, Operation and Maintenance Instructions - Manual (Page 12)

Page 12 LAARS HEATING SYSTEMS
2. EDP/EDN ONLY: Connect 1¼" thermostatic
union to system supply connection in direction
designated with union.
3. Pipe the discharge of the relief valve, full size, to
a drain or in a manner to prevent injury in the
event of pressure relief.
4. Install an air purger in flow supply line as shown
in Figures 15, 16 or 17.
5. Install automatic float type air vent on air scoops.
6. Install a diaphragm expansion tank in boiler
outlet piping. To ensure sufficient expansion
volume for the hydronic system water, due to
heat-up and cool-down during normal operation,
a #30 or larger expansion tank must be used on
EBP combo units.
Figure 18. Hydronic Piping EBP/EDP for Systems Zoned with Circulators.
Figure 19. Hydronic Piping EDP for Low-Temp and/or Multi-Temp Systems.
NOTE: Never install expansion tank and auto
fill valve on return.
7. If necessary, install a properly sized circulator
with optional isolation valves in supply beyond
expansion tank.
Caution
All hot water pipes must be installed with a
minimum 1" (25mm) clearance from combustible
materials.
8. Connect boiler feed water supply with shut off
valve to inlet connection of automatic fill valve.
Locate in boiler outlet piping.
9. If codes require, install suitable back flow
preventer between automatic fill valve and city
main.