background image

C

D

B

K

J

C

H

C

H

J

180

°

F

Water
To
Bldg.

Conventional 
Tank

140

°

F Water

To Bldg.

To

Drain

To Drain

Cold 

Water

To

Drain

Pump
PW Series
VW Series

140

°

F Water

Return  From 

Bldg.

180

°

F Water

Return  From 

Bldg.

Cold Water

Pump
PW Series
VW Series

16

Figure 17 – Two-Temperature Hot Water Supply System with Vertical Tank for Models VW and PW Water Heaters

recommended pipe size, a larger pump may be
required.  Consult the factory if in doubt.

6.

Install a pipe in the tank drain fitting that goes to a
floor sink, and install a drain valve.  If a floor sink
is not available, install a hose bib.

7.

Hot water tanks in an existing installation are
likely to have a 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 is glass-lined, it should be equipped
with a suitable magnesium anode.  It is good
practice to replace the anode when it is
approximately 50% used.  The factory warranty
on a glass-lined tank will be void if a satisfactory
anode is not in place at the time of a failure or if it
is consumed by cathodic action.

5.

Make sure the tank connections in the heater-
tank circulating loop are the proper size as listed
in Section 2H.  If tappings are smaller than the

LEGEND
B – Check Valve
C – Check Valve
D – Tempering Valve
H – Throttling Valves in Building Loop Returns
J – Circulating Pump for Return Loop
K –Service Valves to Isolate Heater and Pump for Service

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...

Reviews: