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attached.

2.

Use the figures in Table III   to provide adequate
gas piping from the gas meter to the heater.

Table III.  Gas Piping Sizes

                   Distance from Gas Meter

                                or Last Stage Regulator

    Model         0-100'

100-200'         200-300'

500

1-1/2"

2"

2"

600

1-1/2"

2"

2-1/2"

715

2"

2"

2-1/2"

850

2"

2-1/2"

2-1/2"

1010

2"

2-1/2"

3"

1200

2-1/2"

3"

3"

1430

2-1/2"

3"

3"

1670

2-1/2"

3"

3"

1825

2-1/2"

3"

3-1/2"

Note:  These figures are for Natural Gas (.65 Sp.
Gr.), and are based on 1/2" water column pressure
drop.  Check supply pressure with a manometer, and
local code requirements for variations.  For LPG,
reduce pipe diameter one size, but maintain a 1"
minimum diameter.  A normal number of Tees and
elbows have been taken into allowance.

3.

A trap (drip leg) must be provided ahead of the
gas controls (see Figure 8 ).  A manual gas
shutoff valve must also be provided for service
convenience and safety.  Check the local codes.

4.

The boiler 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 psig.  The boiler must
be isolated from the gas supply piping system by
closing its individual manual gas shutoff valve
during any pressure testing of the gas supply
piping system at test pressures equal to or less
than 1/2 psig.

5.

Provide gas supply pressure to the heater as

follows:

            Natural Gas

       LPG

   Min. (inches
   water column)

    Max. (inches
   water column)

Note:  The heater and all other gas appliances
sharing the heater gas supply line must be firing at
maximum capacity to properly measure the inlet
supply pressure.  Low gas pressure could be an
indication of an undersized gas meter and/or
obstructed gas supply line.

6.

The correct burner manifold gas pressure is
stamped on the rating plate.  The regulator is
preset at the factory and normally requires no
further adjustment.

7.

The gas manifold and control assembly was
tested and conform to the safe lighting and other
performance criteria specified in the latest
editions of ANSI Z21.13 and CGA 3.3 Low
Pressure Boiler Standard.

8.

Before operating the boiler, the complete gas
supply system and all connections must be tested
for leaks using a soap solution.  Do not use raw
flame
.

CAUTION:  Since some leak test solutions (including
soap and water) may cause corrosion or stress
cracking, the piping must be rinsed with water after
testing, unless it has been determined that the leak
test solution is noncorrosive.

2E.  Electrical Wiring

WARNING:  The heater must be electrically grounded
in accordance with the most recent edition of the
National Electrical Code, ANSI/NPA 70.  In Canada,
all electrical wiring to the heater should be in
accordance with the Canadian Electrical Code, CSA
C22.1 Part 1.  Do not rely on the gas or water piping
to ground the metal parts of the heater.  Oftentimes,
plastic pipe or dielectric unions isolate the heater
electrically.  Service and maintenance personnel who
work on or around the heater may be standing on wet
floors and could be electrocuted by an underground
heater.

1.

Check heater wiring and pump for correct
voltage, frequency and phase.  If the pump circuit
is other than 115V, check to see that the heater is

8

Figure 8 – T-Fitting Sediment Trap Installation

 Per Rating Plate

  9                          14

Summary of Contents for VW

Page 1: ...nce can cause injury or property damage Refer to this manual For assistance or additional information consult a qualified installer service agency or the gas supplier FOR YOUR SAFETY WHAT TO DO IF YOU...

Page 2: ...ical Heater Installation with Base for Combustible Floors Ex A 5 Figure 3 Typical Heater Installation with Base for Combustible Floors Ex B 5 Figure 4 Typical Heater Installation with Base for Combust...

Page 3: ...ional Electrical Code ANSI NFPA 70 and or in Canada CAN1 B149 requirement 3 Figure 1 Boiler Configuration When required by the authority having jurisdiction the installation must conform to American S...

Page 4: ...changer tubes is kept high enough to prevent scaling from hard water and low enough to avoid corrosion from soft water Ninety five percent of the urban areas in the country have water that is compatib...

Page 5: ...ustion air supply may result in incomplete combustion sooting of the heat exchanger and unsafe operation of the heater 2 In general these requirements specify that small heater rooms should be provide...

Page 6: ...enings one at floor level and one at the ceiling so the total net free area could be double the figures indicated For special conditions refer to the latest edition of ANSI Z223 1 or in Canada CAN1 B1...

Page 7: ...nch of vent diameter Longer total lengths shown in venting tables are based on maximum capacity not condensation factors 7 When the installation of a draft fan is necessary in connecting a venting sys...

Page 8: ...ity to properly measure the inlet supply pressure Low gas pressure could be an indication of an undersized gas meter and or obstructed gas supply line 6 The correct burner manifold gas pressure is sta...

Page 9: ...Relief Valve Hot Water Hot Water Storage Tank Floor Automatic Tempering Valve Cold Water Tempered Water 24 3 Pressure relief valve lever must be tripped at least once a year to insure that waterways a...

Page 10: ...ections or other restrictive fittings in heater to tank loop 2 The Model IW heater is designed for use in a system without a hot water storage tank The hot water supply line to usage point must have a...

Page 11: ...k Valve Throttling Valve Hot Water To Bldg Conventional Tank To Drain To Drain To Drain Pump PW Series VW Series Optional Cold Water Supply When Adequate Tank Opening Not Available Service Valves Hot...

Page 12: ...ion in the building hot water piping system Cold Water Supply Return Loop Pump see note 2 Check Valve To Drain Conventional Tank To Drain To Drain Recommended Increasing One Pipe Size From C W Connect...

Page 13: ...Cold Water Supply Building Loop To Building Service Connections Building Loop Circulator See Note 3 Building Loop To Minimum Pipe Size 1 Thru 850 1 1 4 1010 Thru 1825 Service Valves For Heater Isolat...

Page 14: ...p and damage the heater through lack of water circulation If for any reason the water supply is turned off temporarily to service a piece of equipment the manual gas valve on the Model IW should be cl...

Page 15: ...roven to be lit Whenever the pilot flame is interrupted the main gas valve closes within 8 10 of a second b Electronically Supervised Standing Pilot System System 16 When pilot flame fails the ignitio...

Page 16: ...in Return Line from Building Loop D Tempering Valve E Venturi Suction Tee H Throttling Valves in Building Loop Returns I Circulating Pump for 180 Building Loop J Circulating Pump for 140 Building Loo...

Page 17: ...deposit of silt on the bottom Therefore it is important to extend the pump suction pipe in the tank to a position near the top Pipe the return from the heater to the bottom of the tank 4 If the tank...

Page 18: ...ting of water occurs 4 Flow Switch Standard on all models Models VW and PW the switch is mounted in the outlet tee connection Model IW the switch is mounted directly in the header outlet The flow swit...

Page 19: ...rs can be achieved by slowly opening the main manual valve The result should be a smooth lighting of the main burners Hi Limit Checkout After running the heater for a long enough period bring the wate...

Page 20: ...on and is a sign of combustion air and or venting problems As soon as any fouling is observed the cause of the fouling should be corrected see Section 5 Troubleshooting Guide The heat b For heaters wi...

Page 21: ...embly is free of debris d Reassemble in reverse order Be sure the heat exchanger baffles are replaced 8 The gas and electric controls installed on heaters are engineered for both dependable operation...

Page 22: ...wired into the pump circuit so that the heater cannot fire unless the pump is running 2 Check to see that all valves in system are open to be sure that water can circulate through the heater and the...

Page 23: ...k 2 adequate height of stack above roof 3 equipment exhausting air from inside of building and 4 proper installation of draft diverter D Gas pressure to burners is D Check gas pressure with excessive...

Page 24: ...National Combustion Company Inc 104 07 180th Street Jamaica NY 11433 718 291 8400 FAX 718 291 6870 Litho in U S A 0610 H2107400A...

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