33
A.
General Guidelines
1. Read and follow all venting, combustion air,
water piping, gas piping and electrical instructions
contained in this manual unless otherwise instructed
in this section.
2. Consult Local Building Codes or National Fuel Gas
Code, NFPA 54/ANSI Z222.3 for restrictions and
instructions on modular boiler installations.
B.
Module Sizing
U.S. Boiler recommends sizing each boiler in a modular
system to provide 20 % of the combined heating load
where ever possible.
C.
Venting
1. Each boiler must have an individual vent pipe.
Refer to Venting Section of this manual for venting
guidelines and options.
WARNING
Do not manifold vent pipes together.
2. The maximum vent length for each boiler is fifty
(50) equivalent feet.
3. The minimum horizontal distance between vent
terminations is one (1) foot. Additional horizontal
distance is desirable to avoid frost damage to the
building. Vent terminations must be at least twelve
(12) inches above the ground plus the expected
snow accumulation.
CAUTION
Installing multiple vent terminations close
together promotes frost buildup on buildings.
To minimize this possibility, extend the distance
from the building to the end of the vent
termination and increase the horizontal distance
between terminations.
4. Multiple vertical vent pipes may be piped through
a common conduit or chase so that one roof
penetration may be made. Each vent termination
must be one (1) foot from other terminations.
D.
Water Piping
(See Table 9 and Figure 21)
Installing a low water cutoff in the system piping of
modular systems is strongly recommended and may be
required by Local Codes.
E.
Gas Piping
1. Refer to National Fuel Gas Code, Local Codes and
Tables 7 and 8 for gas pipe sizing.
VII. MODULAR INSTALLATION
Table 9: Modular Boiler Water Manifold Sizing
2. Each boiler must be piped as shown in Figure 16.
WARNING
If gas pressure in the building is above ½ psig,
an additional gas pressure regulator is required.
Using one additional regulator for multiple
boilers may result in unsafe boiler operation.
The additional regulator must be able to properly
regulate gas pressure at the input of the smallest
boiler. If the regulator cannot do this, two or
more additional regulators are required. Consult
regulator manufacturer and/or local gas supplier
for instructions and equipment ratings.
F.
Electrical
1. Each boiler must be provided with a fused
disconnect and service switch.
2. Install wiring in accordance with requirements of
authority having jurisdiction. In the absence of such
requirements, follow the National Electric Code,
NFPA 70 and/or CSA C22.1 Electric Code.
G.
Modular Boiler Control Systems
Contact a controls manufacturer such as Honeywell or
Tekmar to properly apply a modular control system.
Common systems may use outdoor temperature, return
water temperature or both to stage the boilers.
Combined Output
(MBH)
Recommended Minimum
Common Water Manifold
Size (NPT)
< 166
1¼”
< 260
1½”
< 550
2”
< 900
2½”
< 2000
3”
Summary of Contents for PVG3
Page 14: ...14 Figure 4 Horizontal Vent Installation III Venting continued...
Page 16: ...16 Figure 7 Attic Offset Figure 6 Vertical Vent Installation III Venting continued...
Page 29: ...29 Figure 17 Wiring Connection Diagram VI Electrical continued...
Page 31: ...31 Figure 19 Circulator Zoned System Wiring Diagram VI Electrical continued...
Page 32: ...32 Figure 20 Zone Valve Zoned System Wiring Schematic VI Electrical continued...
Page 34: ...34 Figure 21 Modular Boiler Piping VII Modular Installation continued...
Page 36: ...36 Figure 22 Operating Instructions VIII System Start up continued...
Page 51: ...51 Figure 29 Flue and Burner Cleanout 1 Burner XI Service continued...
Page 54: ...54 XII Repair Parts continued...
Page 56: ...56 XII Repair Parts continued...
Page 60: ...60 XII Repair Parts continued...
Page 67: ...67 SERVICE RECORD DATE SERVICE PERFORMED...
Page 68: ...68 U S Boiler Company Inc P O Box 3020 Lancaster PA 17604 1 888 432 8887 www usboiler net...
