American Water Heater 98 Gallon 80 Thermal Efficiency UltraLow NOx Heavy Duty Commercial Gas Water Heater User Manual

							21
PERIODIC MAINTENANCE
VENTING SYSTEM INSPECTION
At	least	 once	a	 year	 a	visual	 inspection	 should	be 	made 	of	 the	 venting 	
system.	 You	should	look	for:
1. 		 Obstructions	 which	could	cause	 improper	 venting.	The 
	 combustion	and	ventilation	air	flow	must	not	be	obstructed.
2.		 Damage	 or	deterioration	 which	could	 cause	 improper	 venting 
	 or	leakage	of	combustion	products.
3.		 Rusted	flakes	around	top	of	water	heater.
Be	 sure	 the	vent	 piping	 is	properly	 connected	 to	prevent	 escape	
of	dangerous	flue	gases	which	could	cause	deadly	asphyxiation.
Obstructions	 and	deteriorated	 vent	systems	 may	present	 serious	
health	risk	or	asphyxiation.
Chemical	 vapor	corrosion	 of	the	 flue	 and	 vent	 system	 may	occur	
if	 air	 for	 combustion	 contains	certain	chemical	 vapors.	Spray	can	
propellants, 	cleaning	 solvents,	refrigerator	 and	air	conditioner 	
refrigerants,	 swimming	pool	chemicals,	 calcium	and	sodium	 chloride, 	
waxes, 	bleach	 and	process	 chemicals	 are	typical	 compounds	 which	
are	potentially	corrosive.
If	 after	 inspection	 of	vent	 system	 you	found	 sooting	 or	deterioration,	
something	 is	wrong.	 Call	the	local	 gas	utility	 to	correct	 problem	 and	
clean	 or	replace	 the	flue	 and	 venting	 before	resuming	 operation	 of	
water	heater.
BURNER INSPECTION
Flood	 damage	 to	a	water	 heater	 may	not	be	readily	 visible	or	
immediately	 detectable.	However,	over	a	period	 of	time	 a	flooded	
water	 heater	 will	create	 dangerous	 conditions	which	can	cause 	
DEATH, SERIOUS BODILY INJURY, OR PROPERTY DAMAGE. 
Contact 	a	 qualified	 installer	or	service	 technician	 to	replace	 a	flooded 	
water	 heater.	 Do	not	 attempt	 to	repair	 the	unit!	 It	must	 be	replaced!
At	 least	 once	 a	year	 a	visual	 inspection	 should	be	made	 of	the	 main	
burner	 and	pilot	 burner,	 see	Figure	 19.	Inspect	 burner	fl	ames	 through 	
viewport.	 Flames	should	be	very	 small	 with	a	blue	 haze	 and	small	
amounts	 of	yellow 	or	 orange	 at	the	 edges.	 After	several	 minutes	 of	
operation	the	burner	screen	may	glow	red.
You	 should	 check	for	sooting.	 Soot	is	not	 normal	 and	will	impair	
proper	combustion.
Soot	 build-up	 indicates	 a	problem	 that	requires	 correction	 before	
further	 use.		Turn	“OFF”	 gas	to	water	 heater	 and	leave	 off	until 	
repairs	 are	made,	 because	 failure	to	correct	 the	cause	 of	the 	
sooting	 can	result	 in	a	fire	 causing	 death,	serious	 injury,	or	
property	damage.
Flame Characteristics
Correct FlameRed/Orange
FIGURE 19.
Natural Gas (Low Nox)Burner  Door Assembly
Use brush on this surface
BurnerPilot Assembly
FIGURE 20.
BURNER CLEANING
If	inspection	 of	the	 burner	 shows	that	cleaning	 is	required,	 turn	
the	 gas	 control	 knob	clockwise	 (		)	 to 	the 	“OFF” 	position, 	
depressing 	slightly.
NOTE:  The knob cannot be turned from “PILOT” to “OFF” 
unless knob is depressed slightly.  DO NOT FORCE.
Check	 the	burner	 to	see	 if	it’s	 dirty	 or	clogged.	 The	burner	 may	be	
cleaned	 with	a	soft	 paint	 brush,	 see	Figure	 20.	Do	not	 use	 a	wire	
brush	 or	any	 tool	that	may	 damage	 the	burner	 screen. 	Important: 	Do 	
not 	use	 the	burner 	if 	the	 burner 	screen	 is	damaged. 	NOTE: 	Damage	
may	be	rips	or	holes	in	the	burner	screen.	Discoloration	is	normal.
HOUSEKEEPING
Fire and Explosion Hazard
Do  not  obstruct combustion air 
openings at the bottom of the 
water heater .
Do not use or store flammable vapor
products such as gasoline, solvents
or adhesives in the same room or area  
near water heater or other appliance.
C an cause serious injury or death.
Vacuum	 around	base	of	water	 heater	 for	dust,	 dirt,	and	 lint	on	a	
regular	basis. 
						

							22
When	checking	 the	Temperature-Pressure	 Relief	Valve	operation,	
make	 sure	that	(1)	no	one	 is	in	 front	 of	or	 around	 the	outlet	 of	the	
Temperature-Pressure	 Relief	Valve	discharge	 line,	and	(2)	that	 the	
water	 discharge	 will	not	 cause	 any	property	 damage,	 as	the	 water	
may	 be	extremely	 hot.	Use	 care	 when	 operating	 valve	as	the	 valve	
may	be	hot.
To	 check 	the	 relief 	valve, 	lift 	the	 lever 	at 	the	 end	 of	valve	 several	 times,	
see	Figure	21.	 The	valve	should	seat	properly	and	operate	freely.
If	 after	 manually	 operating	 the	valve,	 it	fails	 to	completely	 reset	and	
continues	 to	release	 water,	immediately	 close	the	cold	 water	 inlet	
to	 the	 water	 heater	 and	drain	 the	water	 heater,	 see	Draining	 And	
Flushing 	on 	page 	24.	 Replace 	the 	Temperature-Pressure 	Relief	 Valve	
with	 a	properly	 rated/sized	 new	one,	 see	Temperature-Pressure 	
Relief	Valve	on	page	11	for	instructions	on	replacement.
DISCHARGE PIPE
TEMPERA TURE-PRESSURERELIEF VA LVE
FIGURE 21.
If	the	 Temperature-Pressure	 Relief	Valve	on	the	 water	 heater	 weeps	
or	discharges	periodically,	this	may	be	due	to	thermal	expansion.
NOTE:	 Excessive	 water	pressure	 is	the	 most	 common	 cause	of	
Temperature-Pressure	 Relief	Valve	leakage.	 Excessive	 water	
system	 pressure	 is	most	 often	 caused	 by	“thermal	 expansion” 	
in	 a	“closed	 system.”	 See	Closed	 Water	Systems	 and	Thermal 	
Expansion	 on	page	 11.	The	 Temperature-Pressure	 Relief	Valve	
is	not	intended	for	the	constant	relief	of	thermal	expansion.
Temperature-Pressure	 Relief	Valve	leakage	 due	to	pressure 	
build	 up	in	a	closed	 system	 that	does	 not	have	 a	thermal 	
expansion	 tank	installed	 is	not	 covered	 under	the	limited 	
warranty.	 Thermal	expansion	 tanks	must	be	installed	 on	all	
closed	water	systems.
DO NOT PLUG THE TEMPERATURE-PRESSURE RELIEF 
VALVE OPENING. THIS CAN CAUSE PROPERTY DAMAGE,   
SERIOUS INJURY OR DEATH.
Explosion Hazard
Te mperature-Pressure Relief  Valve
must comply with  ANSI Z21.22-
CSA 4.4 and  ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided .
Can result in overheating and
excessive tank pressure .
Can cause serious injury or death.
RECOMMENDED PROCEDURE FOR PERIODIC 
REMOVAL OF LIME DEPOSITS FROM TANK TYPE 
COMMERCIAL WATER HEATERS
The	amount	 of	calcium	 carbonate	 (lime)	released	 from	water	 is	
in	 direct	 proportion	 to	water	 temperature	 and	usage,	 see	chart. 	
The	 higher	 the	water	 temperature	 or	water	 usage,	 the	more	 lime	
deposits	 are	dropped	 out	of	the	 water.	 This	is	the	 lime	 scale	 which	
forms	in	pipes,	heaters	and	on	cooking	utensils.
INSTALLED	 IN	SUITABLE	 AREA:	To	insure	 sufficient	 ventilation 	
and	 combustion	 air	supply,	 proper	clearances	 from	the	water 	
heater	 must	be	maintained.	 See	Facts	 to	Consider	 About	The		
Location	 section.	Combustible	 materials	such	as	clothing, 	
cleaning	 materials,	 or	flammable	 liquids,	etc.	must	 not	be	placed 	
against	or	adjacent	to	the	water	heater	which	can	cause	a	fire.
ANODE ROD INSPECTION
Property Damage Hazard
 Av oid water heater damage.
 Inspection and replacement of anode rod required .
CAUTION
The	anode	 rod	is	used	 to	protect	 the	tank	 from	 corrosion.	 Most	hot	
water	 tanks	are	equipped	 with	an	anode	 rod.	The	 submerged	 rod	
sacrifices	 itself	to	protect	 the	tank.	 Instead	 of	corroding	 the	tank,	
water	 ions	attack	 and	eat	away	 the	anode	 rod.	This	 does	 not	affect	
water’s	 taste	or	color.	 The	rod	must	 be	maintained	 to	keep	 the	tank	
in	operating	condition.
Anode	 deterioration	 depends	on	water	 conductivity,	 not	necessarily	
water	 condition.	 A	corroded	 or	pitted	 anode	 rod	indicates	 high	water	
conductivity	 and	should	 be	checked	 and/or	replaced	 more	often	than		
an	 anode 	rod	 that	 appears	 to	be	 intact.	 Replacement	 of	a	depleted	
anode	 rod	can	 extend	 the	life	of	your	 water	 heater.	 Inspection	 should	
be	 conducted	 by	a	qualified	 service	technician,	 and	at	a	minimum	
should	be	checked	annually	after	the	warranty	period.
Artificially	 softened	water	is	exceedingly	 corrosive	because	the	
process	substitutes	sodium	ions	for	magnesium	and	calcium	ions.
The	 use	of	a	water	 softener	 may	decrease	 the	life	of	the	 water 	
heater	tank.
The	 anode	 rod	should	 be	inspected 	after	 a	maximum	 of	three	 years	
and	 annually	 thereafter	 until	the	condition	 of	the	 anode	 rod	dictates	
its	replacement.	
NOTE:  Artificially	 softened	water	requires	 the	anode	 rod	to	be	
inspected	annually.
The	 following	 are	typical	 (but	not	all)	signs	 of	a	depleted	 anode	rod:
•	 The	majority	of	the	rods	diameter	is	less	than	3/8”.
•	 Significant	 sections	of	the	 support	 wire	(approx.	 1/3	or	more	 of	
the	anode	rod’s	length)	are	visible.
TEMPERATURE-PRESSURE RELIEF VALVE TEST
Burn hazard.
Hot water discharge. Keep clear of  Temperature-
Pressure Relief V alve
discharge outlet.
It	 is	 recommended	 that	the	Temperature-Pressure	 Relief	Valve	
should 	be 	checked 	to	 ensure 	that	 it	is	 in	operating 	condition 	
every	6	months. 
						

							23
Lime	accumulation	 not	only	 reduces	 the	life	of	the	 equipment	 but	
also	 reduces	 efficiency	 of	the	 heater	 and	increases	 fuel	consumption.
The	 usage	 of	water	 softening	 equipment	 greatly	reduces	 the	
hardness	 of	the	 water.	 However,	 this	equipment	 does	not	always	
remove	 all	of	the	 hardness	 (lime).	For	this	 reason	 it	is	 recommended 	
that	a	regular	schedule	for	deliming	be	maintained.
The	 time	 between	 cleaning	will	vary	 from	 weeks	 to	months	 depending 	
upon	water	conditions	and	usage.
The	 depth	 of	lime	 buildup	 should	be	measured	 periodically.	 Heaters	
equipped	 with	cleanouts	 will	have	 about	 2”	of	lime	 buildup	 when	
the	 level	 of	lime	 has	reached	 the	bottom	 of	the	 cleanout	 opening.	 A	
schedule	 for	deliming	 should	then	be	set	 up,based	 on	the	 amount	
of	 time	 it	would	 take	for	a	1”	 buildup	 of	lime.	 It	is	 recommended	 that	
the	water	heater	initially	be	inspected	after	6	months.
Example	1:
Initial	 inspection	 after	6	months	 shows	1/2”	of	lime	 accumulation.	
Therefore,	the	heater	should	be	delimed	once	a	year.
Example	2:
Initial	inspection	after	6	months	shows	2”	of	lime	accumulation.
Therefore,	the	heater	should	be	delimed	every	3	months.
FIGURE 22.
DELIMING SOLVENTS
UN•LIME	 is	recommended	 for	deliming.	 UN•LIME	 is	a	patented 	
food	 grade	 acid	which	 is	safe	 to	handle	 and	does	 not	create	 the	
harmful	fumes	which	are	associated	with	other	products.
UN•LIME	 may	be	obtained	 from	your	dealer,	 distributor	 or	water 	
heater	 manufacturer.	 Order	Part	Number	 9005416105,	 1	gallon, 	
packed	 4	gallons	 per	case	 or	Part	 Number	 9005417105,	 5	  
gallon	container.
NOTE:	Un•Lime	is	not	available	for	use	in	Canada.
Hydrochloric	 base	acids	 are	not	recommended	 for	use	 on	glass 	
lined tanks.
Observe	handling	instructions	on	label	of	product	being	used.
TANK CLEANOUT PROCEDURE
The	 following	 practices	 will	ensure	 longer	life	and	 enable	 the	unit	 to	
operate	at	its	designed	efficiency:
1.	 Once 	a	 month	 the	heater	 should	 be	flushed.	 Open	the	drain 	valve 	
and	 allow	 two	gallons	 of	water	 to	drain 	from	 the	heater.	 Inlet	water 	
valve	should	remain	open	to	maintain	pressure	in	tank.
2.	 A 	cleanout	 opening	is	provided	 for	periodic	 cleaning	 of	the	 tank.		
Gas	 must	 be	shut	 off	and	 heater	 drained	 before	opening	 cleanout.
To	clean	heater	through	cleanout	opening,	proceed	as	follows:
1.	 Drain	heater.
2.	 Remove	outer	cover	plate	from	lower	side	of	heater	jacket.
3.	 Remove	 six	(6)	hex	 head	 screws	 securing	 tank	cleanout	 plate	
and	remove	plate.
4.	 Remove	 lime,	scale,	 or	sediment	 using	care	not	to	damage	 the	
glass	lining.
5.	 Inspect 	cleanout 	plate	 gasket, 	if 	new	 gasket 	is 	required, 	see 	
replacement	parts	list	for	item	number.
6.	 Install	 cleanout	plate.		Be	 sure	 to	draw	 plate	up	tight 	by	 tightening 	
screws	securely.
7.	 Replace	outer	jacket	cover	plate.
FIGURE 23.9.	 In	 some	 water	 areas	 the	sediment	 might	not	be	removed 	
by	 this	 method	 and	may	 result	 in	the	 water	 heater	 making	
rumbling	 or	boiling	 noises. 	To	 dissolve	 and	remove	 these	more	
stubborn	 mineral	deposits,	 UN•LIME	 Professional	 Delimer	
should	be	used.
DELIMING USING FLO-JUG METHOD
UN•LIME	 in	the	 5	gallon	 size	is	recommended	 for	deliming	 of	all	
models.	 Contact	your	local	 dealer,	 distributor	 or,	water	 heater	
manufacturer.
PREPARE THE WATER HEATERTo	 delime	 the	water	 heater	 using	the	Flo-Jug	 method,	 first	prepare	
the	heater	for	deliming.
Explosion Hazard
Flammable hydrogen gases
may be present .
Keep all ignition sources away
from faucet when turning on
hot water.
Do	not	 smoke	 or	have	 open	 flame	 or	sparks	 in	vicinity	 of	heater.	 Do	
not	 mix	 UN•LIME	 with	other	 chemicals.	 Do	not	 allow	 contact	 with	
magnesium,	aluminum	or	galvanized	metals.
Chemical Hazard
• Product contains phosphoric acid.
• Keep out of reach of children.
• Use rubber or neoprene gloves.
UN•LIME	 contains	phosphoric	 acid.	In	case	 of	external	 contact,	
flush	 with	cool	 water.	 If	irritation	 persists,	 get	medical	 attention.	 If	
swallowed,	 give	1 	or	 2	glasses	 of	water	 or	milk	 and	call 	physician.
Get	 immediate	 medical	attention	 for	eyes.	 Keep	out	of	reach 	
of	children.
NOTE: THE USE OF RUBBER OR NEOPRENE GLOVES IS 
RECOMMENDED, ESPECIALLY IF YOU HAVE ANY OPEN 
SORES OR CUTS TO AVOID UNNECESSARY IRRITATION 
OR DISCOMFORT.
1.  Turn	 off	fuel	 and/or	 power	supply	 to	heater.	 Also,	turn	off	power	
to	 any	 electrical	 device	or	equipment,	 which	is	attached,	 or	part	
of	the	system.
2.  Open	 hot	water	 side	of	faucet	 closest	 to	heater	 and	allow	 water	
to	run	until	it	is	cool	enough	to	handle	safely. 
						

							24
3. Close	cold	water	inlet	valve	to	heater.
4.  Connect	 hose	to	drain	 valve	 at	bottom	 of	heater	 and	start	
draining	heater	into	suitable	floor	drain	area.
5.  Remove	 relief	valve	 while	heater	 is	draining.	 NOTE:	Do	not	
replace	 relief	valve	 until	deliming	 is	completed.	 Relief	valve	
opening	 will	also	 act	as	a	vent	 in	case	 of	possible	 contact	
between	 the	delimer	 and	the	anode	 rod(s),	 which	may	produce 	
flammable	hydrogen-air	mixtures.
6.  If	relief	 valve	 appears	 to	be	 limed-up,	 place	it	in	 a	clean	 glass	or	
plastic	 container	 adequate	 in	size	 so	that	 you	can	pour	 enough 	
UN•LIME®	 into	the	container	 to	cover	 the	valve	 and	allow	 space 	
for	 foaming.	 When	foaming	 stops,	run	fresh	 cool	water	 into	the	
container	and	rinse	the	relief	valve	for	a	few	minutes.
7.  If	heater	 does	not	drain	 completely	 after	a	reasonable	 length	
of	 time,	 turn	off	the	 main	 water	 supply	 valve	to	stop	 water	 from	
entering	 the	tank	 due	to	a	by-pass	 problem	 or	defective	 cold	
water	 inlet	valve.	 Also,	check	 for	clogged	 drain	valve	 opening. 	
Heater	must	be	completely	drained	before	introducing	UN•LIME.
8.  Remove	 the	cleanout	 cover	and	place	 a	clean	 plastic	 bucket	 next	
to	the	cleanout	opening.
Partially	 open	the	cold	 water	 inlet	valve	 to	allow	 time	to	accomplish 	
the	following	and	then	close	the	valve.
While	 the	water	 is	being	 run	through	 the	tank,	 insert	 a	stiff 	
wire,	 copper	 tube	flattened	 at	one	 end	or	an	 opened	 wire	coat	
hanger	 through	 the	cleanout	 opening	and	scrape	 out	any	 loose 	
deposits	 of	scale	 or	sediment.	 This	is	an	 economical	 way	to	avoid 	
unnecessary	usage	of	the	deliming	solution.
Repeat	 the	opening	 and	closing	 of	the	 cold	 water	 inlet	valve	 as	
necessary	 but	be	sure	 the	heater	 is	completely	 drained	when	
ready	to	introduce	the	UN•LIME.
Upon	 completion,	 reinstall	the	cleanout	 cover	and	use	a	new 	
cleanout	cover	gasket	(part	number	9004099215).
Remove	the	drain	valve.
9.  Install	 the	long	 plastic	 male	adapter	 insert	fitting	into	the	drain 	
valve	 opening	 of	heater	 after	applying	 Teflon	tape	or	paste	 to	
threads.	 Tighten	firmly	by	hand	 and	use	wrench	 or	adjustable 	
pliers	 to	check	 for	secure	 connection.	 Do	not	 over	 tighten	 to	avoid 	
damage	to	threads	and	fittings.
PREPARE THE UP-N-DOWN TRANSFER KITThe	 next	 step	is	the	 preparation	 on	the	 Up-N-Down	 Transfer	Kit,	if	
you	have	not	already	done	so:
1.	 With 	the 	5	 gallon	 Up-N-Down 	container	 in	the 	vertical	 position,	 unscrew	
the	 plastic	 vent	cap	in	the	 handle	 and	pierce	 the	plastic	 membrane 	
over	the	vent	boss	under	the	cap	to	allow	the	container	 to	vent.
  Note:	 	 If	your	 container	 does	not	have	 the	vent	 cap	and	 vent	
boss,	 drill	a	3/16”	 (4.76mm)	 hole	in	the	 handle.		 When	you	have	
finished	 deliming	 you	will	be	able	 to	plug	 this	drilled	 vent	with	the	
stainless	steel	screw	that	is	supplied	with	the	kit.
2.	 Remove	 the	container’s	 cap	and	 cut	plastic	 membrane	 located	in	
the	 3/4”	 IPT	opening	 in	cap.		 Take	 care	to	not	 damage	 the	threads.
3.	 Find	 the	3/4”	 male	 adapter,	 apply	teflon	 tape	to	the	 threaded	 end	
and	screw	it	into	the	3/4”	IPT 	opening	in	the	cap.
4.	 Put	 cap	with	 male	 adapter	 back	on	the	 container	 and	slide	 3/4”	
hose	 over	end	of	male	 adapter	 and	fasten	 in	place	 using	hose	
clamp	provided.
DELIME USING FLO-JUG METHOD5.	 Slide	 the	hose	 clamp	 over	end	of	hose	 and	slide	 hose	 over	the	
male	 adapter	 in	the	 water	 heater	 drain	opening	 and	secure	 in	
place	using	hose	clamp.
6.	 Lift	 container	 to	the	 “Pour”	 Position	 being	careful	 to	keep	 the	vent	 in	the 	
handle	above	the	liquid	level	and	pour	the	UN•LIME	into	the	heater.
7.	 Lower	 container,	 you	may	 have	 to	place	 the	container	 on	its	empty 	
carton	 to	prevent 	the	 UN•LIME	 from	flowing	 back	into	the	container.
8.	 Let	 UN•LIME	 remain	in	the	 heater	 for	5	minutes	 and	then	 lower	
the	container	to	the	“Drain”	Position.
9.	 Deliming	 activity	is	indicated	 by	foaming	 on	the	 surface	 of	the	
UN•LIME.		If	there	is	deliming	activity,	repeat	steps	6	thru	8.
Normally,	 lime	removal	 will	be	completed	 within	one	hour.	 Severe	
build-up	 of	lime	 may	 take	longer	 than	an	hour	 to	complete	 descaling.
Note:	 To	check	 UN•LIME	 for	continued	 use,	place	 some	 scale	or	white 	
chalk	 in	a	glass	 with	a	small	 amount	 of	UN•LIME.	 If	the	 material	 is	
vigorously	 dissolved	by	the	 UN•LIME,	 it	can	 be	reused;	 if	not,	 the	
UN•LIME	should	be	replaced.
If	 the	 temperature-pressure	 relief	valve	 on	the	 appliance	 weeps	or	
discharges	 periodically,	 this	may	 be	due	 to	thermal	 expansion.	 You	may	
have	 a	check	 valve	installed	 in	the	 water	 line	or	a	water	 meter	 with	a	
check	 valve.	Consult	 your	local	 water	 supplier	 or	service	 technician 	for 		
further	 information.	 Do	not	 plug	 the	temperature-pressure	 relief	valve.
DRAINING AND FLUSHING
It	is	 recommended	 that	the	water	 heater	 storage	 tank	be	drained 	
and	 flushed	 every	6	months	 to	reduce	 sediment	 buildup.	The	
water	 heater	 should	 be	drained	 if	being	 shut	down	 during	 freezing 	
temperatures.	 See	Installation	 Considerations	 in	this	 manual	 for	the	
location	of	the	water	heater	components	described	below.
Burn harzard.
Hot water discharge.
Keep  hands   clear  of  drain
valve  discharge.
TO DRAIN THE WATER HEATER STORAGE TANK:1.  Turn	 off	the	 gas	 supply	 at	the	 Main	 Gas	Shutoff	 Valve	if	the 	
water	heater	is	going	to	be	shut	down	for	an	extended	period. 	
2.  Ensure	the	cold	water	inlet	valve	is	open.
3.  Open	 a	nearby	 hot	water	 faucet	 and	let	the	 water	 run	until	 the	
water	is	no	longer	hot.
4.  Close	the	cold	water	inlet	valve	to	the	water	heater.
5.  Connect	 a	hose	 to	the	 water	 heater	 drain	valve	 and	terminate	
it to an adequate drain.
6.  Open	 the	water	 heater	 drain	valve	 and	allow	 all	the	 water	 to	
drain	from	the	storage	tank.
7.  Close	 the	water	 heater	 drain	valve	 when	 all	water	 in	the	
storage	tank	has	drained.
8.  Close	the	hot	water	faucet	opened	in	Step	4.
9.  If	the	 water	 heater	 is	going	 to	be	 shut	 down	 for	an	extended	
period,	the	drain	valve	should	be	left	open.
TO FLUSH THE WATER HEATER STORAGE TANK:1.  Ensure	the	cold	water	inlet	valve	is	open.
2.  Open	 a	nearby	 hot	water	 faucet	 and	let	the	 water	 run	until	 the	
water	is	no	longer	hot.	 Then	close	the	hot	water	faucet.
3.  Connect	 a	hose	 to	the	 drain	 valve	 and	terminate	 it	to	 an	
adequate drain.
4.  Ensure	 the	drain	 hose	is	secured	 before	and	during	 the	entire	
flushing	 procedure.	 Flushing	is	performed	 with	system	 water	
pressure	applied	to	the	water	heater.	
5.  Open	the	water	heater	drain	valve	to	flush	the	storage	tank.	
6.  Flush	 the	water	 heater	 storage	 tank	to	remove	 sediment	 and	
allow	the	water	to	flow	until	it	runs	clean.
7.  Close	 the	water	 heater	 drain	valve	 when	 flushing	 is	completed.
8.  Remove	the	drain	hose.
9.  Fill	the	water	heater	-	see	Filling	 The	Water	Heater	in	this	manual.
10.  Turn	 on	the	 gas	 supply	 to	the	 water	 heater	 at	the	 Main	 Gas	
Shutoff	Valve.
11.  Allow	 the	water	 heater	 to	complete	 several	heating	 cycles	to	
ensure	it	is	operating	properly.
SERVICE
Before	 calling	for	repair	 service,	 read	the	“Start	 Up	Conditions”	 and	
“Operational	 Conditions”	found	in	the	 “For	 Your	 Information”	 section	
of	this	manual.
If	 a	 condition	 persists	or	you	 are	uncertain	 about	the	operation	 of	the 	
water	 heater	 contact	 a	service	 technician.	 If	you	 are	not	thoroughly 	
familiar	 with	gas	codes, 	your	 water	 heater, 	and	 safety	 practices, 	contact 	
your	gas	supplier	or	qualified	installer	to	check	the	water	heater.
Use	 the	”Leakage	 Checkpoints”	 guide	to	check	 a	“Leaking” 	  
water	 heater.		 Many	suspected	 “Leakers”	are	not	leaking	 tanks.		Often	
the	source	of	the	water	can	be	found	and	corrected.
Read	 this	manual	 first.	Then	 before	 checking	 the	water	 heater	 make	
sure	 the	gas	 supply	 has	been	 turned	 “OFF”,	 and	never	 turn	the	gas	
“ON”	before	the	tank	is	completely	full	of	water.
Never	 use	this	water	 heater	 unless	 it	is	 completely	 filled	with	water.		 To	
prevent	 damage 	to 	the 	tank,	 the	tank	 must	 be	filled	 with	water.		 Water	must	
flow	 from	 the	hot	water	 faucet	 before	 turning	 “ON”	gas	to	the	 water	 heater. 
						

							25
LEAKAGE CHECKPOINTS
A.	 Water	at	the	 draft	 hood	 is	water	 vapor	 which	 has	condensed	 out	
of	 the	 combustion 	products.		 This	is	caused	 by	a	problem	 in	the	
vent.	Contact	the	gas	utility.
B.		*Condensation	 may	be	seen	 on	pipes	 in	humid	 weather	 or	pipe	
connections	may	be	leaking.
C.		*The	anode	rod	fitting	may	be	leaking.
D.		Small	 amounts	of	water	 from	temperature-pressure	 relief	valve	
may	 be	due	 to	thermal	 expansion	 or	high	 water	 pressure	 in	your	
area.
E.		*The	 temperature-pressure	 relief	valve	 may	be	leaking	 at	the	
tank	fitting.
F.		 Water	 from	a	drain	valve	 may	be	due	 to	the	 valve	being	 slightly	
opened.
G.		*The	drain	valve	may	be	leaking	at	the	tank	fitting.
H.		Combustion	 products	contain	water	vapor	 which	 can	condense	
on	 the	 cooler	 surfaces	 of	the	 tank.		 Droplets	 form	and	drip	onto	
the	 burner	 or	run	 on	the	 floor.	 	 This	is	common	 at	the	 time	 of	
start-up	after	installation	and	when	incoming	water	is	cold.
I.		 Water	 in	the	 water	 heater	 bottom	 or	on	 the	 floor	 may	be	from	
condensation,	 loose	connections,	 or	the	 relief	 valve.		 DO	NOT 	
replace	 the	water	 heater	 until	a	full	 inspection	 of	all	 possible	 water	
sources	is	made	and	necessary	corrective	steps	taken.
Leakage	 from	other	 appliances, 	water	 lines,	or	 ground	 seepage 	
should	also	be	checked.
*	 To	 check	 where	 threaded	 portion	enters	tank,	insert	 cotton	
swab	 between	 jacket	opening	 and	fitting.		 If	cotton	 is	wet,	 follow	
“Draining	 and	Flushing”	 instructions	 in	the	 “Periodic	 Maintenance” 	
section	 and	then	 remove	 fitting.		Put	pipe	 dope	 or	teflon	 tape	on	
the	 threads	 and	replace.		 Then	follow	 “Filling	 the	Water	 Heater”	
instructions	in	the	Installation	Requirements	section. 
						

							26
TROUBLESHOOTING GUIDELINES
These	guidelines	should	be	utilized	by	a	qualified	service	agent.
	 Problem Cause Solution
WATER LEAKSImproperly	sealed,	hot	or	cold	supply	connection,	relief	
valve,	drain	valve,	or	thermostat	threads.
Tighten	threaded	connections.
Leakage	from	other	appliances	or	water	lines. Inspect	other	appliances	near	water	heater.
Condensation	of	flue	products. Refer	to	CONDENSATION.
LEAKING T&P VALVE Thermal	expansion	in	closed	water	system.
Install	thermal	expansion	tank	(DO	NOT	plug	T&P	valve).
Improperly	seated	valve. Check	relief	valve	for	proper	operation
	
(DO	NOT 	plug	T&P	valve).
SMELLY WATER High	sulfate	or	mineral	content	in	water	supply.
Drain	and	flush	heater	thoroughly,	then	refill.
Bacteria	in	water	supply. Chlorinate	or	aerate	water	supply.
PILOT WILL NOT LIGHT Gas	control	knob	not	positioned	correctly.
Refer	to	LIGHTING	INSTRUCTIONS.
Main	gas	supply	off. Turn	on	main	gas	shutoff	valve.
Thermocouple	malfunction. Replace	pilot	assembly	and/or	thermocouple.
BURNER WILL NOT  STAY LIT Thermocouple	malfunction.
Replace	pilot	assembly	and/or	thermocouple.
Defective	Gas	Control. Replace	Gas	Control.
PILOT OUTAGE Dirty	pilot	burner.
Clean	pilot	assembly.
Thermocouple	malfunction. Replace	pilot	assembly	and/or	thermocouple.
Defective	Gas	Control. Replace	Gas	Control.
Thermocouple	tip	is	not	in	contact	with	pilot	flame. Insert	thermocouple	correctly.
NOT ENOUGH   HOT WATER Heater	not	lit	or	thermostat	not	on.
Refer	to	LIGHTING	INSTRUCTIONS.
Thermostat	set	too	low. Refer	to	TEMPERATURE	REGULATION.
Heater	undersized. Reduce	hot	water	use.
Low	gas	pressure. Contact	your	gas	supplier.
Incoming	water	is	unusually	cold. Allow	more	time	for	heater	to	re-heat.
Leaking	hot	water	pipes	or	fixtures. Have	plumber	check	and	repair	leaks.
High	temperature	limit	switch	activated. Contact	a	service	technician	to	determine	cause.
WATER TOO HOT Thermostat	set	too	high. Refer	to	TEMPERATURE	REGULATION.
WATER HEATER SOUNDSCondensation	dripping	on	burner. Refer	to	CONDENSATION.
SIZZLING	OR 	
RUMBLING Sediment	or	calcium	in	bottom	of	heater	tank.
Clean	sediment	from	tank.		Refer	to	DRAINING
	
instructions	in	Maintenance	section	of	manual.
SOOTING Improper	combustion. No	adjustment	available.	Contact	a	service
	
technician 	to	determine	cause.
VENT GAS ODORS Lack	of	supply	air.
Contact	a	service	technician	to	determine	cause.
Improperly	installed	vent	piping.
Downdraft.
Poor	combustion. 
						

							27
WATER PIPING DIAGRAMS
October 2009 | Printed in U.S.A. | © A. O. Smith For Technical Information and Automated Fax Service, call 800-527-1953 or visit www.hotwater.com.  AOSCG61130 | PAGE 1 of 1
  A. O. Smith Corporation reserves the right to make product changes or im\
provements without prior notice.NOTES:
1. Preferred piping diagram.
2.  The temperature and pressure relief valve setting shall not exceed press\
ure rating of any component in the system.
3.  Service valves are shown for servicing unit. However, local codes shall govern their usage.4. The Tank Temperature Control should be wired to and control the pump between the w\
ater heater(s) and the storage tank(s).
5. The water heater’s operating thermostat should be set 5 degrees F higher than the Tank Temperature Control.SINGLE FLUE - (1 UNIT)
LEGEND
TEMPERAT URE & PRESSURE
RELIEF VA LV EPRESSURE RELIEF VA LV ECIRCULATING PUMPTANK TEMPERAT URE CONTROLDRAIN
FULL PORT BALL VA LV
E
TEMPERATURE GAGEWATER FLOW SWITCH
CHECK VA LV
E
WARNING: THIS DRAW ING SHOWS SUGGESTEDPIPING CONFIGURATION AND OTHER DEVICES;
CHECK WITH LOCAL CODES AND ORDINANCES
FOR ADDITIONAL REQUIREMENTS.
FINISHED
FLOOR HOTC
OLD
COLD
EXPANSION
TANK
COLD WATER
SUPPLY
PIPE T&P TO
OPEN DRAIN 
						

							28October 2009 | Printed in U.S.A. | © A. O. Smith For Technical Information and Automated Fax Service, call 800-527-1953 or visit www.hotwater.com.  AOSCG61140 | PAGE 1 of 1
  A. O. Smith Corporation reserves the right to make product changes or im\
provements without prior notice.NOTES:
1. Preferred piping diagram.
2.  The temperature and pressure relief valve setting shall not exceed press\
ure rating of any component in the system.
3.  Service valves are shown for servicing unit. However, local codes shall govern their usage.
4.  The Tank Temperature Control should be wired to and control the pump between the w\
ater heater(s) and the storage tank(s).
5.  The water heater’s operating thermostat should be set 5 degrees F higher than the Tank Temperature Control.SINGLE FLUE - (1 UNIT) WITH VERTICAL STORAGE TANK
LEGEND
TEMPERAT URE & PRESSURE
RELIEF VA LV EPRESSURE RELIEF VA LV ECIRCULATING PUMPTANK TEMPERAT URE CONTROLDRAIN
FULL PORT BALL VA LV
E
TEMPERATURE GAGEWATER FLOW SWITCH
CHECK VA LV
E
WARNING: THIS DRAW ING SHOWS SUGGESTEDPIPING CONFIGURATION AND OTHER DEVICES;
CHECK WITH LOCAL CODES AND ORDINANCES
FOR ADDITIONAL REQUIREMENTS.
FINISHED
FLOOR HOTC
OLD
EXPANSION
TANK
COLD WATER
SUPPLY
HOT WATER
RETURN FROM 
FIXTURES
HOT WATER
TO FIXTURES
ALT. COLD
WATER CONNECTION
PIPE T&P TO
OPEN DRAIN 
						

							29October 2009 | Printed in U.S.A. | © A. O. Smith For Technical Information and Automated Fax Service, call 800-527-1953 or visit www.hotwater.com.  AOSCG61150 | PAGE 1 of 1
  A. O. Smith Corporation reserves the right to make product changes or im\
provements without prior notice.NOTES:
1. Preferred piping diagram.
2.  The temperature and pressure relief valve setting shall not exceed press\
ure rating of any component in the system.
3.  Service valves are shown for servicing unit. However, local codes shall govern their usage.
4.  The Tank Temperature Control should be wired to and control the pump between the w\
ater heater(s) and the storage tank(s).
5.  The water heater’s operating thermostat should be set 5 degrees F higher than the Tank Temperature Control.SINGLE FLUE - (1 UNIT) WITH HORIZONTAL STORAGE TANK
LEGEND
TEMPERAT URE & PRESSURE
RELIEF VA LV EPRESSURE RELIEF VA LV ECIRCULATING PUMPTANK TEMPERAT URE CONTROLDRAIN
FULL PORT BALL VA LV
E
TEMPERATURE GAGEWATER FLOW SWITCH
CHECK VA LV
E
WARNING: THIS DRAW ING SHOWS SUGGESTEDPIPING CONFIGURATION AND OTHER DEVICES;
CHECK WITH LOCAL CODES AND ORDINANCES
FOR ADDITIONAL REQUIREMENTS.
FINISHED
FLOOR HOTC
OLD
EXPANSION
TANKCOLD WATER
SUPPLYHOT WATER
RETURN FROM 
FIXTURES
HOT WATER
TO FIXTURES
ALTERNATE
LOCATION
PIPE T&P TO
OPEN DRAIN 
						

							30October 2009 | Printed in U.S.A. | © A. O. Smith For Technical Information and Automated Fax Service, call 800-527-1953 or visi t www.hotwater.com. AOSCG61160 | PAGE 1 of 1
  A. O. Smith Corporation reserves the right to make product changes or im\
provements without prior notice.NOTES:
1.  Preferred piping diagram.
2.  The temperature and pressure relief valve setting shall not exceed press\
ure rating of any component in the system.
3.  Service valves are shown for servicing unit. However, local codes shall govern their usage.
4.  The Tank Temperature Control should be wired to and control the pump between the w\
ater heater(s) and the storage tank(s).5. The water heater’s operating thermostat should be set 5 degrees F higher than the Tank Temperature Control.SINGLE FLUE  - (1 UNIT) WITH MIXING VALVE TWO TEMPERATURE
LEGEND
TEMPERATURE & PRESSURE
RELIEF VALVEPRESSURE RELIEF VALVECIRCULATING PUMPTANK TEMPERATURE CONTROLDRAIN
FULL PORT BALL VALVETEMPERATURE GAGEWATER FLOW SWITCH CHECK VALVE
WARNING: THIS DRAWING SHOWS SUGGESTEDPIPING CONFIGURATION AND OTHER DEVICES;
CHECK WITH LOCAL CODES AND ORDINANCES
FOR ADDITIONAL  REQUIREMENTS.
HOT WATER
RETURN MINIMUM
10´´ to 12´´ HOT WATER OUTLET
TEMPERED WATER
RETURN TEMPERED
WATER
OUTLET
COLD WATER
SUPPLY
LINE
TEMPERATURE CONTROL COLD
HOT
EXPANSION
TANK
PIPE T&P TO
OPEN DRAIN
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