LAARS HEATING SYSTEMS
Page 12
1K. Electrical Wiring
Follow these instructions to make the necessary
initial electrical connections.
1.
Remove the two screws attaching the front cover
of the control box.
2.
There are five wires coiled in the area on the
right side of the control box, supplied with wire
nuts: two black wires twisted together, two white
wires, and a separate brown wire.
3.
Follow the schematics in Figures 10 & 11.
Remove the wire nut from the two black wires,
and connect the hot lead from the 115V power
supply, and the neutral lead to the white wires
and the neutral side of the pump. The brown wire
attaches to the hot side of the pump.
4.
Attach the leads from the wall thermostat to the
R and W terminals on the terminal strip, located
on the left side of the control box.
5.
Check the boiler wiring and pump for correct
voltage, frequency and phase. If the pump circuit
is other than 115V, be sure there is an
appropriate transformer or relay installed. The
pump relay is suitable for pumps of 3/4 HP or
less.
6.
For systems with multiple zone pumps or valves
(see Figure 12).
A means of disconnecting the electrical supply
must be provided within sight of the boiler. The pump
and boiler must be wired as shown to insure that the
pump is running whenever the boiler is firing.
WARNING
The boiler must be electrically grounded in
accordance with the requirements of the authority
having jurisdiction or, in the absence of such
requirements, with the latest edition of the national
Electrical Code, ANSI/NFPA 70, in the U.S. and
with the latest edition of CSA C22.1 Canadian
Electrical Code, Part 1, in Canada. Do not rely on
the gas or water piping to ground the metal parts of
the boiler. Plastic pipe or dielectric unions may
isolate the boiler electrically. Service and
maintenance personnel who work on or around the
boiler may be standing on wet floors and could be
electrocuted by an ungrounded boiler.
Hi-Limit Switch: Factory setting is 190°F
(88ºC). This setting is correct for normal operations,
and should only be changed by an authorized service
technician. Under no Circumstances should the setting
exceed 220°F (104ºC).
Flow Switch: If the system includes a flow
switch, it should be wired in series with the high-limit
switch. The boiler will not fire unless the pump is
running and the flow switch is closed.
Field installed safety devices and operating
controllers, such as valve end switches, relays, timers,
and outdoor temperature reset devices, can be
connected to the boiler through the wall thermostat
circuit. Do not exceed a draw of 30VA on the
transformer secondary.
Heat Anticipator: For single zone installations,
the wall thermostat heat anticipator should be set at
1.0A. For multi-zone installations, have a qualified
electrical technician make the necessary measurements
and properly set the thermostats.
1L. Filling the System
It is crucial to the efficient operation of the
system that all air be removed from the circuit. For
this reason, an air scoop and vent should be located
close to the boiler outlet, and there should be a
minimum distance between cold water feed and
system purge valve.
1.
When the system has been completely installed,
close all air vents and open the makeup water
valve. Allow the circuit to fill slowly.
2.
If a make-up water pump is employed, adjust the
pressure to provide a minimum of 12 psi (83kPa)
at the highest point in the circuit. If a pressure
regulator is also installed in the line, adjust it to
the same pressure.
3.
Close all valves. Purge one circuit at a time as
follows:
a.
Open one circuit drain valve and let water
drain out for at least 5 minutes. Be certain
there are no air bubbles visible in the water
stream before closing the drain valve.
b.
Repeat this procedure for each circuit.
4.
Open all valves after all circuits have been
purged.
5.
Run the system circulating pump for a minimum
of 30 minutes with the boiler shut off.
6.
Open all strainers in the system, and check for
debris.
7.
Recheck all air vents as described in Step 3.
8.
Inspect the liquid level in the expansion tank,
with the system full of water, and under normal
operating pressure, to ensure proper water level
in the expansion tank.
9.
Start up boiler according to the procedures
described in Section 2 and operate the system,
including the pump, boiler, and radiation units,
for one hour.
10.
Recheck the water level in the expansion tank. If
it exceeds 1/2 of the volume of the tank, open the
tank drain and reduce the water level.
11.
Shut down the entire system, and vent all
radiation units and high points in the system.
