Navien NP-180, Service Manual

Page: 98 / 179

©N
avien
Am
eri
c
a
I
n
c
. 20
1
0
NR/NP
series servi
c
e Manua
l
96
Versi
o
n 2.0
5.13. 22Error
Error occurrence conditions and check items.
Description Error
22E
Heat exchanger
input
temperature
sensor
shortcircuit
Check items
If
an err
o
r
(
s
ho
rt
-c
ir
c
uit
: 1
20
ȕ o
r
h
i
gh
er
)
in t
h
e
h
eat e
xch
an
g
er in
p
ut te
mp
erature
sens
o
r is
d
ete
c
te
d,
t
h
e s
y
ste
m d
is
pl
a
y
s t
h
e 22
E
err
o
r
m
essa
g
e
(cl
eare
d
aut
om
ati
c
a
lly)
o
n t
h
e re
mo
te
co
ntr
oll
er an
d
t
h
e
PCB
.
Th
e
bo
i
l
er
m
aintains t
h
e Sa
f
et
y-
S
h
ut
dow
n
status.
1
.
Ch
e
c
k i
f
t
h
e
h
eat e
xch
an
g
er in
p
ut te
mp
erature sens
o
r
co
nne
c
t
o
r is
w
et
d
ue t
o
an
y
reas
o
n
,
in
cl
u
d
in
g l
eaka
g
e.
2.
R
e
pl
a
c
e t
h
e
d
e
f
e
c
te
d h
eat e
xch
an
g
er in
p
ut te
mp
erature sens
o
r.
3
.
R
e
pl
a
c
e t
h
e
PCB
.
Is the hot water thermistor 1
normal?
Yes
No
Check connector
Replace hot water thermistor 1
Resistance between two red wires of CN 13 is from
0.8 to 20k ohm at normal condition.
Caution: Before measuring resistance of the thermistor,
remove the connector from the PCB.