15
Rev. D 1-19-00
P/N 471243
GAS CONNECTIONS
REGULATED MANIFOLD
PRESSURE TEST
1. Attach the manometer to the heater jacket.
2. Shut off the main gas valve.
3. Remove 1/8" NPT plug on the outlet side of the
valve and screw in the fitting from the manometer
kit.
4. Connect the manometer hose to the fitting.
5. Fire the heater.
6. The manometer must read 4" WC for natural gas,
11" WC for propane gas,
while
the heater is
operating.
7. For adjustment, remove the Regulator Adjustment
Cap and using a screwdriver turn the screw
clockwise to increase - counterclockwise to
decrease gas pressure; see Figure 13.
GAS LINE INSTALLATIONS
Before installing the gas line, be sure to check which gas
the heater has been designed to burn. This is important
because different types of gas require different gas pipe
sizes. The rating plate on the heater will indicate which
gas the heater is designed to burn. Table 3 shows which
size pipe is required for the distance from gas meter to the
heater. The table is for natural gas at a specific gravity of
.65 and propane at specific gravity of 1.5.
When sizing gas lines, calculate three (3) additional feet
of straight pipe for every elbow used.
When installing the gas line, avoid getting dirt, grease or
other foreign material in the pipe as this may cause damage
to the gas valve, which may result in heater failure.
The gas meter should be checked to make sure that it will
supply enough gas to the heater and any other heaters that
may be used on the same meter.
The gas line from the meter will usually be of a larger size
than the gas valve supplied with the heater. Therefore a
reduction of the connecting gas pipe will be necessary.
Make this reduction as close to the heater as possible.
The heater and any other gas appliances must be
disconnected from the gas supply piping system during
any pressure testing on that system, (greater that ½ PSIG).
The heater and its gas connection must be leak tested
before placing the heater in operation.
Do not use flame
to test the gas line.
Use soapy water or another nonflam-
mable method.
A manual main shutoff valve must be installed
external to the heater.
Installation (contd.)
Figure 13.
Maximum inlet gas pressure
10" WC
14" WC
Minimum inlet gas pressure
5" WC
12" WC
Normal manifold pressure
4" WC
11" WC
* All Readings are taken with heater fired. Any
adjustments made with heater off will give
incorrect readings.
LAGUNA GAS
PRESSURE SETTINGS*
Table 4.
Pipe Sized For Length Of Run In Equivalent Feet
Table 3.
1"
3/4"
1/2"
Model
Nat
LP
Nat
LP
Nat
LP
100 DSI
20'
50'
50'
150'
150'
600'
100 MV
20'
50'
50'
150'
150'
600'
Do not install the gas line union inside the heater
cabinet. This will void your warranty.
WARNING
CAUTION
Natural
Propane
Maximum inlet gas pressure
10" WC
14" WC
Minimum inlet gas pressure
5" WC
12" WC
Normal high altitude
3" WC
7" WC
manifold pressure
Natural
Propane
High Altitudes
(2500-7000 ft. Above Sea Level)
Normal Altitudes
(0-2500 ft. Above Sea Level)
The use of Flexible Connectors (FLEX) is NOT
recommended as they cause high gas pressure drops.
P
IL
O
T A
D
J
IN
ON
OFF
VENT
TH
TP
TH
TP
Regulator Adjustment Cap
Regulator Adjustment Cap
SIT valve
Robertshaw
valves
