20
5. When constructing a piping tree to install LWCO
select fittings (tees, elbows etc) and nipples to have
the same size (NPT) as boiler supply connection.
At minimum, 1-1/4” tee with ¾” branch outlet is
required to connect the probe LWCO to the supply
piping. See Figure 10.
DO NOT REDUCE THE
SIZE OF NEAR BOILER SUPPLY FITTINGS
AND NIPPLES
.
6. Installation of manual shutoff valve located above
the LWCO and the boiler is recommended to allow
servicing. Thus LWCO probe can be removed for
inspection without draining the heating system. An
annual inspection of the probe is recommended.
7. The presence of water covering properly installed
LWCO probe will cause the normally open contact
of the LWCO to close, thus providing continuity of
the 24 VAC service to the boiler gas valve. When
water level drops below probe, LWCO contact
opens up breaking 24V supply to gas valve and
preventing the boiler to fire.
8. 2012 compliant PVG gas hot water boilers have
a “plug-in” provision in factory wiring that will
accept optional 24VAC probe LWCO harness
connector. The optional LWCO kit (P/N 104083-
01) includes 24VAC probe LWCO, Harness and
Instructions addressing piping, wiring and testing
after installation.
C.
Optional Auxiliary Limit Installation
1. Some jurisdictions may require the use of an
Auxiliary Limit control with a hot water boiler as a
redundant safety control.
IV. WATER PIPING AND TRIM (continued)
Figure 11: Recommended Auxiliary Limit Location
2. The recommended location for an Auxiliary Limit
on gas hot water boilers is in the supply piping. See
Figure 11 for recommended location.
3. Piping and fittings required to install an Auxiliary
Limit
are field supplied
.
4. When constructing a piping tree to install an
Auxiliary Limit select fittings (tees, elbows etc)
and nipples to have the same size (NPT) as boiler
supply connection. At minimum, 1-1/4” tee with
1/2” branch outlet is required to install the limit
well into the supply piping. See Figure 11.
DO
NOT REDUCE THE SIZE OF NEAR BOILER
SUPPLY FITTINGS AND NIPPLES
.
5. When boiler water temperature reaches or exceeds
Auxiliary Limit setting, the limit normally closed
contact will open, thus interrupting the 24 VAC
service to the boiler gas valve. When boiler water
temperature drops below limit differential, limit
contact closes restoring 24V supply to gas valve and
allowing the boiler to fire.
6. Gas hot water boilers equipped with Intelligent
Hydronic Control have a “plug-in” provision in
factory wiring that will accept optional 24VAC
Auxiliary Limit harness connector. The optional
Auxiliary Limit kit (P/N 103696-01) includes
24VAC Auxiliary Limit, Well, Harness and
Instructions addressing wiring and testing after
installation.
D.
Connect system supply and return piping
to boiler.
See Figures 14 and 15. Maintain minimum ½ inch
(13 mm) clearance from hot water piping to
combustible materials.
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...
