HeatStation™ CONDENSING WATER BOILER
15
34-1161 05/17
6
GAS SUPPLY AND PIPING
Verify the type of gas specified on rating plate is supplied to the unit. This unit is orificed for operation up to 2000 feet
altitude. Appliance Btu/h input derates 4% per 1000 feet elevation above sea level. Consult Factory for installations
above 2000 feet elevation.
6.1 Gas Train and Controls Certification
NOTE
: The gas train and controls assembly provided on this unit have been tested under the applicable Nationally
Recognized Standard to comply with safety and performance criteria such as ignition, combustion and safety shutdown
operation.
6.2 Gas Control Trains
All models include the following gas control train components: manual shutoff valve, a combination gas valve
containing two safety shutoff valves, an internally vent limited zero governor type regulator, a manual test valve and
manifold pressure taps, and high and low gas pressure switches.
WARNING: Do not adjust or remove any screws or bolts on gas train control components which are secured
with a red or blue sealing compound. In addition to voiding warranties and certification listings, such
adjustment or disassembly can cause improper operation which could result in property damage, personal
injury or death.
6.3 Inlet Pressure
Measure at the inlet pressure tap located at the main gas cock. The inlet pressure must remain within the minimum
and maximum values while the unit is at rest and while the unit is operating at maximum firing rate.
6.4 Manifold Pressure
Measure at the pressure tap located downstream side of the manual valve closest to the burner. The rated manifold
pressure appears on the product data label located near the front of the appliance.
6.5 Gas Piping Size
The following table identifies the gas connection size.
MODEL
SIZE NPT
1000 & 1250 HS
1"
1500, 1750 & 2000 HS
1½"
Do not use the gas pipe connection size to determine the gas supply piping. Designing and sizing a gas supply piping
system requires consideration of many factors and must be done by a gas supply piping expert. Always follow NFPA
54 National Fuel Gas Code for gas pipe sizing and gas pipe system design. The following charts provide examples of
some of the information used by the gas supply piping expert to determine proper pipe sizes.
Use the values in the following table to add the equivalent straight pipe for each elbow or tee to obtain the total distance
from the meter:
INLET PRESSURE
NAT. GAS
Propane
Maximum Static Pressure (Inches-Water Column)
14.0"
13"
Minimum Flow Pressure (Inches-Water Column)
3.5"
8"
CONVERT FITTINGS TO EQUIVALENT STRAIGHT PIPE*
Diameter Fitting (inches)
¾" 1" 1¼" 1½" 2"
3"
4"
5"
Equivalent Length of Straight Pipe (feet) 2'
2'
3'
4'
5'
10' 14' 20'