Boiler Feed Systems - Lattner Boiler Company H.E. Instruction Manual

2. Combination Gas Valve
Some Lattner gas trains include combination gas valves.
Combination gas valves simultaneously function as gas
pressure regulators, flame failure controls, pilot gas
valves, and main gas valves. Combination gas valves
may be supplied with either thermocouple (standing)
pilots or spark-ignited (intermittent) pilots. Combination
gas valves are only available on boilers 10 hp and
smaller.
3. Diaphragm Gas Valve
Some Lattner gas trains include diaphragm gas valves.
Diaphragm gas valves simultaneously function as gas
pressure regulators and main gas valves. Separate pilot
gas valves must be used with a diaphragm gas valve.
Diaphragm gas valves may be supplied with either
thermocouple (standing)
(intermittent) pilots.
4. Motorized Gas Valve
With the motorized gas valve, the main gas valve and
pressure regulator are two separate components. The
motorized gas valve is a two piece valve. The lower
section is the valve body, which is a plunger valve. The
upper section is the actuator. The actuator has a small
built-in hydraulic system. The hydraulic system opens
and closes the valve. The motorized gas valve is a gas
valve only, and has no other functions. This gas train
requires a separate main gas pressure regulator, pilot
gas pressure regulator and pilot valve.
a. Spark-Ignited Pilot
The boiler will be supplied with a flame safeguard
control and an ignition transformer. With these
controls, the boiler will have a spark-ignited pilot.
This system will shut off the main and pilot gas
within four seconds of a pilot failure.
b. Thermocouple Pilot
The boiler will have a pilot switch and a
thermocouple for igniting the main burners.
NOTE: For additional information on the gas train refer to
the assembly prints and product literature sheets.
5. Gas Supply Pipe
The gas pipe to the boiler must be at least the same size
as the gas train supplied with the boiler. DO NOT
reduce.
6. Drip Leg
Gas supply piping must be installed with a proper drip
leg ahead of any gas train components.
7. Gas Supply Pressure
Natural Gas: Supply pressure should be between 6" and
11" water column ahead of the gas pressure regulator.
Minimum supply pressure when the boiler is operating
pilots or spark-ignited
should be 4-1/4" to 4-1/2" water column. Liquid
Propane: Supply pressure is normally 11" water column.
WARNING: NEVER use Teflon tape on any part of the
gas train piping. This will void any warranty on the gas
train assembly.
8. Codes & Standards
All gas piping must be done in accordance with all
applicable codes (National Fuel Gas Code, utility
company requirements, local building codes etc.).
K. Boiler Feed Systems
1. Condensate Return Systems
a. Make-Up Water Supply
Connect city water line to the float valve provided
with the boiler feed system.
LV5 through LV16 use 1/2" NPT
R1-Jr through R2 use 1/2" NPT
Install a manual shut-off valve and union in the
water line.
b. Pump Suction Line
This is pre-piped from the factory with an isolation
valve and strainer.
c. Pump Discharge Line
DO NOT reduce. Use 1" NPT pipe and fittings
between pump and boiler. Install two spring-loaded
check valves. Install a hand shut-off valve between
the last check valve and the boiler. Keep the
number of elbows and fittings to a minimum.
d. Condensate Return Vent
Condensate return tank must be properly vented to
atmosphere. Vent should discharge through the
roof or through a wall to the outside. Do not reduce
the vent pipe size.
LV5 through LV16 use 1" NPT
R1-Jr through R2 use 1" NPT
e. Overflow
Pipe to floor drain. Overflow connection should be
at least as large as the condensate return.
f. Drain Connection
Pipe to floor drain. Install a valve in the line. 1" NPT
line is sufficient.
2. Solenoid Water Valve
a. Water Pressure
This system will work only if the water supply
10