INSTALLATION AND OPERATION INSTRUCTIONS
1-32
DC SERIES BOILERS / WATER HEATERS
DC 15-95, DC 15-96, DC 20-125, DC 33-160
GAS PIPING
The boiler / water heater should normally have an inlet gas pressure of at least
7.0" w.c. for natural gas and 11" w.c. for propane gas. For either fuel, the inlet
pressure shall be no greater than 14.0" w.c. Confirm this pressure range is
available with your local gas supplier.
The inlet gas connection of the boiler’s gas valve is 1/2" NPT (male).
Adequate gas supply piping shall be provided with no smaller than 1/2" Iron Pipe
Size (e.g. Iron Pipe Size (IPS) and using a 1" w.c. pressure drop, in accordance
with the following chart:
MODEL
1/2" IPS
3/4" IPS
1" IPS
DC Series (Natural Gas)
20'
70'
200'
DC Series (Propane)
50'
200'
600'
Table 7: Maximum Pipe Length (ft) – DC series 33-160 boiler
Gas piping must have a sediment trap ahead of the boiler / water heater’s gas
valve
(see Figure 32).
A manual shutoff valve must be located outside the boiler,
in accordance with local codes/standards. All threaded joints in gas piping should
be made with an approved piping compound resistant to the action of natural
gas/propane. Use proper hangers to support gas supply piping as per applicable
codes.
The boiler / water heater must be disconnected or otherwise isolated from the
gas supply during any pressure testing of the system at test pressures in excess
of 1/2 psig. Dissipate test pressure prior to reconnecting. The boiler / water
heater and its gas piping shall be leak tested before being placed into operation.
•
The boiler / water heater and its individual shutoff valve must be disconnected
from the gas supply piping system during any pressure testing of that system
at test pressures in excess of 1/2 psi (3.5 kPa).
•
The boiler / water heater must be isolated from the gas supply piping system
by closing, disconnecting and capping its individual manual shutoff valve
during any pressure testing of the gas supply piping system at test pressures
equal to or greater than 1/2 psi (3.5 kPa).
The gas valve is provided with pressure taps to measure gas pressure upstream
(supply pressure) and downstream (manifold pressure) of the gas valve
(see
Figure 31).
Note that manifold pressure varies slightly in accordance with firing
rates with the modulating series boilers / water heaters, but will always be close
to 0" w.c.
1.8
Figure 32: Gas Piping
Figure 31: Gas Valve
WARNING
This boiler / water heater model
can burn either Natural gas or
Propane. Refer to section 3.3
for further instruction.
If a boiler / water heater is to
be converted from one fuel
to another, a conversion kit
must be ordered prior to the
conversion. The conversion
kit must be installed according
to the detailed instructions
supplied with the kit.
Failure to perform the required
fuel conversion correctly can
result in serious injury or death.
NOTE
It is essential to check gas
supply pressure to each boiler /
water heater with a manometer
or other high-quality precision
measuring device. Pressure
should be monitored before
firing the boiler, when the
regulator is in a “lock-up”
condition and during operation,
throughout the boiler’s full
modulation range.
Pay special attention to retrofit
situations where existing
regulators may have an over-
sized orifice and/or worn seats,
causing pressure “creep” and
high lock up pressures.
