System Piping - Dunkirk PWXL Installation, Operation & Maintenance Manual

1. Place boiler in the selected location (as near chimney as pos-
sible.) Your boiler is shipped assembled. You need only to install
the Relief Valve and a drain line to carry any water or steam to a
drain.
2. Install Relief Valve into the ¾" pipe on the top of the boiler.
Figure 5. Use ¾" Pipe and an elbow (not furnished) to carry
the water or steam to a nearby drain. Do not connect directly to
a drain but leave an air gap. No shutoff of any description shall
be placed between the safety relief valve and the boiler, or on
discharge pipes between such safety valves and the atmosphere.
Installation of the safety relief valve shall conform to the require-
ments of the ANSI/ASME Boiler and Pressure Vessel Code, Sec-
tion IV. The manufacturer is not responsible for any water dam-
age. Install Drain Valve in lower left side of boiler as marked.
3. Connect Supply and Return Lines to boiler. The connections
may require certain additional fittings and parts, see (Figures 5
and 6).
4. This boiler is equipped with 1¼" supply and return connections
on the right side of the boiler.
In connecting the cold water supply to the water inlet valve, make sure
that a clean water supply is available. When the water supply is from a
well or pump, a sand strainer should be installed at the pump.
A hot water boiler installed above radiation level must be equipped
with a low water cutoff device. A periodic inspection is necessary, as
is flushing of float type devices, per manufactures specific instruction.
Refer to local codes for low water cut-off requirements.
For Use With Cooling Units
1. This boiler, when used in connection with chilled water systems,
must be installed so that the chilled water is piped parallel with
the heating boiler. Appropriate valves must be used to prevent
the chilled water from entering the heating boiler (Figure 6).
2. When this boiler is connected to heating coils located in air
handling units where they may be exposed to refrigerated air
circulation, the piping system shall be equipped with flow control
valves or other automatic means to prevent gravity circulation of
the boiler water during the cooling cycle.
Low Design Water Temperature Systems (Below 140º)
3. If the boiler is to be used in a heating system where water tem-
peratures below 140ºF are desired (e.g. radiant floor heating) a
3-way or 4-way mixing valve or suitable alternative is required to
prevent low temperature return water from entering the boiler.

SySTEm pipiNg

Follow the mixing valve manufacturer's installation instructions.
4. The minimum design return water temperature to the boiler to
prevent condensation in the boiler and venting is 120ºF. The
minimum high limit setting is 140º F.
See
Figure 5 -Typical Hot Water Piping
Cool Water Inlet
Relief Valve
Figure 6 - Chilled Water Piping
Valves A & B - Open For Heating; Closed For Cooling
Valves C & D -Closed For Heating; Open For Cooling
10
Circulator
Air Vent
Supply Main
Filtrol
Gauge
Sensor Wire
Return Line