Gas Piping - Harsco Industrial MODU-FIRE FORCED DRAFT N750 Installation & Owner's Manual

3.5.6 Removing an Existing Boiler
When an existing boiler is removed from a common venting system, the common venting system is likely to be too
large for proper venting of the appliances remaining connected to it.
At the time of removal of an existing boiler, while the other appliances remaining connected to the common
venting system are not in operation, the following steps should be followed with each appliance remaining
connected to the common venting system placed in operation:
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and horizontal pitch and determine that there is no
blockage or restriction, leakage, corrosion or other deficiency which could cause an unsafe condition.
3. Insofar as is practical, close all building doors and windows and all doors between the space in which the
appliances remaining connected to the common venting system are located and other spaces of the
building. Turn on clothes dryers and any appliances not connected to the common venting system. Turn
on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum
speed. Do not operate a summer exhaust fan. Close fireplace dampers.
4. Place the appliance being inspected in operation. Follow the lighting instructions. Adjust the thermostat
so that the appliance will operate continuously.
5. Test for spillage at the draft hood relief opening after 5 minutes of main burner operation. Use the flame
of a match or candle or smoke from a cigarette, cigar or pipe.
6. After it has been determined that each appliance remaining connected to the common venting system
properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers
and any other gas-burning appliance to their previous conditions of use.
Any improper operation of the common venting system should be corrected so the installation conforms with the
National Fuel Gas Code, ANSI Z223.1 and CSA B149 Installation Code. When resizing any portion of the
common venting system, the common vent system should be resized to approach the minimum size as
determined using the appropriate tables.
3.6 G P
AS IPING
Before making the gas hook-up, make sure the boiler is being supplied with the type of fuel shown on the boiler
nameplate.
The boiler must be installed such that the gas system components are protected from water (dripping, spraying,
rain, etc.) during appliance operation and service (circulator replacement, control replacement, etc.)
The boiler is factory fire-tested and adjusted for proper combustion with a natural gas supply pressure of 7 inches
W.C. Typical supply gas pressure is 7 inches W.C. for natural gas (11 inches W.C. for propane). The gas train
Minimum Air Requirements – SCFM
MFD MODEL Min Required SCFM
750
1000
1500
2000
21
MODU-FIRE® Forced Draft Gas-Fired Boiler
188
251
364
501