LAARS EDN Series - Installation, Operation and Maintenance Instructions - Manual (Page 10)

Page 10 LAARS HEATING SYSTEMS
WARNING
Failure to install a hot water tempering (mixing)
valve (12) creates a scalding hazard with potential for
serious bodily injury. Some brands of tempering
(mixing) valves are not designed as anti-scald valves.
Where domestic water is supplying multiple
apartments or large whirlpool tubs, additional storage
tank may be connected as shown in Figure 13. The
bronze circulator shown must be connected to tank
aquastat and must not run continuously. If the
circulator is wired to run continuously, unit's domestic
water flow switch will keep the unit in domestic water
priority, and no water will be allowed to be sent to the
heating system.
3.3 Anti-Freeze — Domestic Water
Endurance EBP units use a flat plate heat
exchanger to heat domestic (potable) water indirectly.
Endurance units are equipped with a Low
Temperature control feature that recognizes when the
boiler water temperature (not the domestic/potable
water temperature) has fallen below 39° (4°C). If this
condition is recognized, the Endurance pump will run
for 5 minutes, or until the boiler water temperature
reaches 45°F (7°C). If the boiler water temperature
remains below 45°F (7°C) for 5 minutes, the appliance
will start its ignition sequence, in hopes of firing, and
heating the boiler water. The display will show [ICE]
during this time.
This feature is intended to assist in protecting the
boiler from freezing conditions, and does not help to
protect any other part of the boiler or water heater
system. This feature will not help to protect the
domestic (potable) water in the system from freezing
conditions.
Power outage, interruption of gas supply, failure
of system components, activation of safety devices,
etc., may prevent a heater from firing. Any time a
heater is subjected to freezing conditions, and the
heater is not able to fire, and/or the water is not
able to circulate, there is a risk of freezing in the
heater or in the pipes in the system. When water
freezes, it expands. This can result in bursting of pipes
in the system, or damage to the heater, which could
result in leaking or flooding conditions.
SECTION 4.
Hydronic Heat Piping
4.1 Hydronic Piping
The appliance incorporates its own circulating
pump and bypass loop and is capable of providing
flow through heating zones, in addition to what it
needs for itself. Model size 110 is capable of providing
flow for two heating zones (up to 67 feet of ¾"
baseboard each), and model 175 is capable of
providing flow for four heating zones (up to 67 feet of
¾" baseboard, each).
EDP/EDN boilers installed in radiant (in floor)
systems and other low mass boilers should be provided
with a buffer/blender tank to assure a controlled supply
temperature, and to prevent short cycling. In radiant
systems utilizing 3-way tempering valves, a bypass
pipe must be installed between supply and return
piping.
1.
EBP ONLY: Connect system supply to 1¼"
supply connection marked “SUPPLY”.
Figure 14. EBP Domestic Water Piping with Recirculating Loop.