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boiler. All pipe is 1/2" NPT.
d.
Water Supply
Connect water supply to the strainer.
L. Electrical Connections
CAUTION:
All electrical work shall be done by a competent
electrician. All wiring must be done in strict accordance with
the National Electrical Code and any state or local codes.
1.
Reconnecting Controls
If the boiler was shipped with controls removed, re
connect the wires according to the wiring diagram. All
wires that need to be reconnected will have a tag
indicating the control or terminals to which they must be
connected.
2.
Electrical Supply
Supply 120 volt single phase from a separate fused
disconnect.
Use a 15 amp circuit breaker or fused disconnect if the
boiler has a solenoid water feed valve or a pump motor
1 /2 hp or less or a motor starter for a three phase pump.
Use a 20 amp circuit breaker or fused disconnect if the
boiler has a 3/4 hp pump motor, 120 volt single phase.
3.
Power Supply
Connect the power supply to the terminals in the panel
box as shown on the wiring diagram. "Hot" side will be
marked L 1. Neutral will be marked L2.
4.
Sec ure Connections
After all wiring is complete and before any power is
supplied to the boiler, be sure all wiring connections are
tight.
M. Before Firing The Boiler
1. Spare Fittings
Check that all unused pipe nipples are plugged or
capped.
2.
Float Block
Remove the float block screwed into the body of the
McDonnell Miller level control. Replace with a malleable
iron plug (supplied with the boiler).
3.
Condensate Return System
M ake sure there is make-up water supply to the tank.
Make sure there is water in the tank.
4. Turn On
Turn on the pump switch. Pump or solenoid valve should
start immediately. If not, see troubleshooting section.
5.
Check for Leaks
While the boiler is filling, check for leaks in the piping
and around boiler. If there are leaks, turn off the pump
switch and fix all leaks before continuing.
6. Solenoid Feedwater Valve
If a solenoid water valve is used, make sure the water
supply is connected.
N. Pressuretrols: Controller & Limit
1. Standard
All Lattner steam boilers will have at least two pressure
switches, a "controller" and a "limit".
2.
Controller
Before the boiler is started, the steam pressure is O psi.
At this point, the controller is in the "ON" condition and
is calling for heat. When the boiler switch is turned on,
the boiler will fire and start generating steam. As the
boiler fires, the steam pressure will rise. When the
steam pressure reaches the controller's set point, the
controller will shut off the burner. As steam is used, the
pressure will begin to drop. When steam pressur � drops
enough, the controller will start the burner again. The
controller will continue to operate in this manner to
maintain boiler pressure.
3. Setting The Controller
page)
On the left side of the pressuretrol is the set point
indicating scale labeled "MAIN". Turn the main scale
adjustment screw until the set point indicator align � with
the desired operating pressure. Turn screw clockwise to
increase pressure,
counterclockwise to decrease
pressure.
4.
Differential
When the boiler pressure reaches the main set point the
controller shuts off the burner. The pressure must drop
by a set amount before the controller will turn on
the burner again. This amount is called the differential.
The differential is adjustable.
5.
Setting The Differential
page)
On the far left side of the pressuretrols is the differential
indicating scale labeled "DIFF". Turn the differential
adjusting screw until the indicator aligns with the
desired differential. A minimum differential will maintain
the boiler pressure closer to the set point. A larger
differential will help prevent rapid on and off cycling of
the boiler.
6. Limit
The limit switch is similar in operation to the controller
but has a slightly higher set point. If the controller fails
to shut off the boiler and the steam pressure continues
to rise, the limit switch will shut down the boiler. The
controller is an operating switch; the limit serves as an
12
(see diagram next
(see diagram next
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