Electrical Connections; Before Firing The Boiler; Pressuretrols: Controller & Limit - Lattner Boiler Company H.E. Instruction Manual

pressure is at least 10 psi higher than the boiler
pressure.
b. Water Inlet
Refer to the boiler assembly print for correct
connection and location of feedwater inlet.
c. Piping
The solenoid water valve assembly shall be piped in
the following order: Y-type strainer, solenoid valve,
spring loaded check valve, globe valve, and 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 (inside
the panel box). 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 L1. Neutral will be marked L2.
4. Secure 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
Make 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 0 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 pressure drops
enough, the controller will start the burner again. The
controller will continue to operate in this manner to
maintain boiler pressure.
a. Setting The Controller
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
aligns with the desired operating pressure. Turn
screw clockwise
counterclockwise to decrease pressure.
3. 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.
11
to increase pressure,