Noritz NR501 Series Use and care manual

SKJ70NL
Rev. 10/13
NR501-OD, NR662-OD
This instructi nal manual is nly intended f r use by a qualified service pr fessi nal r auth rized N ritz
NR501, NR662 Series Heat Exchanger
Replacement
M del Include:
Page 1
N ritz America C rp rati n
11160 Grace Avenue, F untain Valley, CA 92708
Ph ne 866-766-7489 Fax [phone]
Service Representative. Any unauth rized use f this manual may result in v iding the warranty.
Please c ntact N ritz Technical Supp rt (866-766-7489) f r additi nal supp rt.

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
1.
(1) Disc nnect electrical p wer t unit
(2) Turn ff gas and water
(3) Rem ve 4 screws
(4) Rem ve drain 2 valves and drain the unit c mpletely
(5) Rem ve the c ver - circuit b ard
2.
(1) Disc nnect the c nnect rs fr m the circuit b ard
(2) Rem ve 2 gr und wires
(3) Rem ve the circuit b ard; there is a screw n middle-
upper f the circuit b ard. Let the circuit b ard hang
utside f the unit
3.
(1) Unplug Flame R d and Igniti n Plug
(2) L sen the cable tie and unplug the freeze preventi n
heater, thermal fuse (2)
(3) Unplug the high limit switch and the thermist r - heat
exchanger
(4) Unplug all wires that attach t the wiring harness
except water serv - main
Page 2
Unplug all wires that attach t the wiring harness and the
b dy f water heater
Pr cedure
Rem ve the fr nt c ver
Disc nnect the c nnect rs fr m the circuit b ard and
rem ve the gr und wire, and the circuit b ard
(4)
(1)
(2)
C ver - Circuit B ard
(3)
Water Serv - Main

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
4.
(1) Rem ve 3 big silver screws n the manif ld plate that
attach the manif ld t the burner
(2) Rem ve 2 smaller silver screws fr m the manif ld
plate that attach the manif ld t the gas valve
(3) Rem ve manif ld plate and unplug the c nnect r
fr m gas s len id valves (3)
5.
(1) Rem ve "C" Clamp (3)
(2) Rem ve the water fl w sens r
Page 3
Pr cedure
Rem ve the manif ld plate
Disc nnect pipes fr m the water fl w sens r and the water
serv - main
(1)
(1)
(2)
Water Fl w Sens r
(2)
(3)

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
6.
(1) Rem ve the 2 set screws n the b tt m f the burner
(2) Rem ve the 2 set screws n the t p f the case
(supp rt b tt m f the assembly)
(3) C pper Heat Exchanger(CU HE), Burner, and Fan will
c me ut in ne secti n. Rem ve fr m the unit.
7.
(1) Rem ve 10 screws h lding the burner t the CU HE
(2) Separate the burner fr m the CU HE
8.
(1) The gasket n the fr nt f the exhaust b x
(2) Fr nt side: Freeze preventi n heater
(3) Left side: High limit switch and thermist r - heat
exchanger
*Replace new O Ring f r the thermist r - heat
exchanger
Page 4
Rem ve heat exchanger c mp nents fr m ld heat
exchanger and put n new heat exchanger
Pr cedure
Rem ve the heat exchanger fr m the case
Replacing the CU HE
(1)
(2)
(1)
(3)
(2)

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
(4) Attach the thermal fuse and 6 clamps fr m 4 sides f
heat exchanger, See 4 views f the heat exchanger t
make sure the thermal fuse is r uted c rrectly
Page 5
Pr cedure
The end f insulati n tube(Black) and the
clamp n the left are lined up
Right side
Install the thermal fuse(White) inside f
the st pper
St pper
Back side
Keep the thermal fuse straight
Left side - 1
Left side - 2
Make sure t r ute the thermal
fuse as sh wn in the diagram t
the right (Left side - 1 & 2)
Fr nt side

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
(5) Place the new freeze preventi n heater with ne that
was shipped in the heat exchanger kit.
Wrap the freeze preventi n heater ar und utlet pipe
fr m the CU HE as sh wn in diagrams
(6) Make sure t r ute the wire as sh wn
in the diagram (6)
9.
(1) Rem ve ld burner gasket and replace with new ne
10.
(1) Inlet t the CU HE
(2) Outlet fr m the CU HE
Page 6
Pr cedure
Place new O Rings n new CU HE
Replace gasket
(2)
(1)
(1)
(5)
(6)
Outlet Pipe
(6)

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
11.
(1) Attach 10 screws ar und perimeter f the burner and
the CU HE
12.
(1) Secure the 2 set screws n the b tt m f the burner
(2) Secure the 2 set screws n the t p f the case
13.
(1) Maintain the high limit switch, the thermist r - heat
exchanger, the thermal fuse, and the freeze
preventi n heater as sh wn in diagram (1)
(2) Maintain wiring harness as sh wn in diagram (2)
(3) Insert the utlet pipe t the water serv - main and
attach "C" clamp
Insert the water fl w sens r t the inlet water
c nnecti n and attach "C" clamp.
And then insert the inlet pipe t the water fl w sens r
and attach "C" clamp.
Page 7
Rec nnect water c nnecti ns
Pr cedure
Reattach the burner and the CU HE
Replace the assembly back inside the case
(1)
(2)
(1)
(2)
(3)

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
14.
(1) Plug the c nnect r t gas s len id valves (3) as right
diagram
(2) C nfirm that there is -ring bef re replace the
manif ld plate
(3) Replace the 2 smaller silver screws fr m the manif ld
plate that attach the manif ld t the gas valve
(4) Replace the 3 big silver screws n the manif ld plate
that attach the manif ld t the burner
(5) Hand tighten 5 screws equally
15.
(1) Replace drain 2 valves
(2) Turn n c ld water shut ff valve sl wly (check f r
leaks ar und “C” clamps)
(3) If y u get leaks shut ff water and re-secure “C”
Clamps
Page 8
Pr cedure
Check f r water leaks
Replace the manif ld plate
(4)
(2)
(1)
BK & BL
wire
O & BL
wire GY & BL
wire
(3)

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
16.
(1) Plug all wires that attach t the wiring harness
(2) Tie wires by cable tie as right diagram
(3) Tie wires by cable tie as right diagram
(4) Put the all wires in the p siti n as sh wn
in diagram (4)
(5) Secure the gr und wire
Page 9
Pr cedure
Plug all wires that attach t the wiring harness and the b dy
f the water heater
(5)
(4)
(2)
Cable Tie
Water Fl w Sens r
Thermist r - Air
Thermist r - C ld Water
Thermist r - H t Water
(3)
Cable Tie

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
(6) Replace the circuit b ard; secure the screw n middle-
upper f the circuit b ard.
Secure the gr und wire.
(7) Rec nnect the c nnect rs t the circuit b ard
(8) Plug the high limit switch and the thermist r - heat
exchanger
(9)
(10)
Plug the freeze preventi n heater, the thermal fuse (2)
and tie the wires by the cable tie
Plug Flame R d and Igniti n Plug.
Page 10
Pr cedure
Take ut all wires n the
utside f the line
(6)
C nfirm that the blue c nnect r is
disc nnected.
(10)
(9)
(8)
Push the yell w
c nnect r.
Left side
Right side

NR501-OD, NR662-OD Series Heat Exchanger Replacement Pr cedure
Diagram
(11) Put all wires as the diagram
(14) Replace the c ver - circuit b ard
24.
(1) Turn n gas
(2) Turn n the unit.
Check f r leaks ar und the manif ld plate and j ining
areas. F r example - Between Burer and CU HE
(3) If y u get leaks shut ff gas and water, re-secure
leaking p ints
25.
(1) Secure the fr nt c ver with 4 screws
Page 11
Replace the fr nt c ver
Pr cedure
Check f r gas leaks and d ing trial perati n
C ver - Circuit B ard
NR501-OD NR662-OD