54
Rinnai Corporation Hydronic Furnace (37AHB) Manual
N
O
T
E
S
:
1.
E
W
T
- En
teri
ng
W
ater Tempe
ratur
e (F)
.
2.
CFM - Air
flow
in (C
ubic Feet per
Minute).
3.
Legs - 3
in
ch
diame
ter
flex
ible du
cts to
diffu
ser
s.
4.
1 MBH =
1000
BTU/H.
5.
Shaded b
ox
represents ra
ting
poin
t; re
fer
to
w
iring diagra
m
for
factory
se
t sp
eed
taps.
6.
Number of 3”
diam
eter
leg
s
spe
cifi
ed i
n ta
ble a
bov
e is
fo
r
rating
poin
t o
nly
(i.e
. a
t Ex
ternal S
ta
tic
Pres
sure
of
0
.5
in. w
c. and
speed
TAP3, TAP1, TAP2
, TAP2
for
AHB45
, AH
B60, AHB75, A
H
B90 re
spe
ctiv
ely
). Final
leg
count i
s
to b
e de
termined
b
y the in
stalli
ng
con
tractor
and i
s to
be
based
on
the
follow
ing formula:
NUMBER OF LEG
S
= TOTAL
AVA
IL
ABLE CFM
(A
T THE S
P
ECI
F
IC
E
S
P)
/ DESI
RED CFM per LEG
(40, 50, or 60 CF
M)
Ex
ample: Giv
en the
design
point
for
A
H
B045 o
f 0
.8
ESP
, Low
fan
speed
(Ta
p5). From
tabl
e 5
.0
, av
ailable CFM i
s
569 and
the d
esir
ed CFM per
leg
is 50
CFM.
Therefore,
Number of Leg
s =
569/50
= 11
.38
rou
nded dow
n to
11
.
0
0
.1
0.
2
0
.3
0.
4
0
.5
0.
6
0
.7
0.
8
0
.9
1.
0
13
43
131
8
1296
1270
1248
1225
1
197
11
68
110
9
1025
889
120
43.
0
42.
2
41
.5
40
.6
39.
9
39.
2
38.
3
37.
4
35.
5
32
.8
28
.4
130
49.
3
48.
4
47
.6
46
.6
45.
8
45.
0
44.
0
42.
9
40.
7
37
.6
32
.7
140
57.
0
56.
0
55
.0
53
.9
53.
0
52.
0
50.
8
49.
6
47.
1
43
.5
37
.8
150
67.
8
66.
5
65
.4
64
.1
63.
0
61.
8
60.
4
58.
9
56.
0
51
.7
44
.9
160
75.
4
74.
0
72
.8
71
.3
70.
1
68.
8
67.
2
65.
6
62.
3
57
.6
49
.9
11
48
112
8
1103
1072
1045
1012
984
955
937
908
690
120
40.
8
40.
1
39
.2
38
.1
37.
2
36.
0
35.
0
34.
0
33.
3
32
.3
24
.5
130
46.
9
46.
1
45
.0
43
.8
42.
7
41.
3
40.
2
39.
0
38.
3
37
.1
28
.2
140
54.
4
53.
4
52
.2
50
.8
49.
5
47.
9
46.
6
45.
2
44.
4
43
.0
32
.7
150
63.
9
62.
8
61
.4
59
.7
58.
2
56.
4
54.
8
53.
2
52.
2
50
.6
38
.4
160
71.
8
70.
6
69
.0
67
.1
65.
4
63.
3
61.
6
59.
8
58.
6
56
.8
43
.2
971
942
911
880
8
4
7
8
1
7
784
751
715
680
642
120
38.
4
37.
2
36
.0
34
.8
33.
5
32.
3
31.
0
29.
7
28.
2
26
.9
25
.4
130
45.
2
43.
9
42
.4
41
.0
39.
5
38.
1
36.
5
35.
0
33.
3
31
.7
29
.9
140
52.
0
50.
4
48
.7
47
.1
45.
3
43.
7
41.
9
40.
2
38.
3
36
.4
34
.4
150
60.
1
58.
3
56
.4
54
.5
52.
5
50.
6
48.
6
46.
5
44.
3
42
.1
39
.8
160
67.
6
65.
6
63
.4
61
.2
59.
0
56.
9
54.
6
52.
3
49.
8
47
.3
44
.7
844
810
777
734
6
9
8
6
6
5
626
581
533
504
466
120
36.
2
34.
8
33
.4
31
.5
30.
0
28.
6
26.
9
24.
9
22.
9
21
.6
20
.0
130
46.
9
45.
0
43
.1
40
.8
38.
8
36.
9
34.
8
32.
3
29.
6
28
.0
25
.9
140
49.
5
47.
5
45
.6
43
.1
41.
0
39.
0
36.
7
34.
1
31.
3
29
.6
27
.3
150
56.
6
54.
3
52
.1
49
.2
46.
8
44.
6
42.
0
39.
0
35.
7
33
.8
31
.2
160
64.
2
61.
6
59
.1
55
.8
53.
1
50.
6
47.
6
44.
2
40.
5
38
.3
35
.4
20
24
30
T
A
B
L
E 5
.2
2
: A
IR
D
E
L
IVER
Y A
N
D
PE
R
F
O
R
M
A
N
C
E D
A
T
A
(
B
O
T
T
O
M
O
R
S
ID
E
R
E
T
U
R
N
w
/ F
A
C
T
O
R
Y
SU
PPL
IE
D
F
IL
T
ER
)
UNI
T
SI
Z
E
EC
M
S
PEE
D
TA
P
SUP
P
ORT
S
C
OOL
IN
G C
A
P
.
RA
NG
E (
T
O
N
S)
EW
T
(
O
F)
NO
M
INA
L
HEA
T
IN
G
CA
P
A
CI
TY
Ex
te
rn
a
l
St
a
ti
c
Pr
es
sur
e
(
E
S
P
) i
n
. W
.C
.
37AHB
06012K
A5 + R
EU
-V
A3237
FF
U(W)-U
S/A
SM
E
A
H
B6
0
+
R9
8
L
Si(
e
)/
A
S
M
E
A
IRFLOW
(
C
FM
)
TA
P
1
(H
)
3.
0
NE
T
HE
A
TI
N
G
CAP
A
CI
TY
(M
B
H
)
A
H
B6
0
+
R9
8
L
Si(
e
)/
A
S
M
E
A
IRFLOW
(
C
FM
)
TA
P
2
(M
H
)
2.
5
NE
T
HE
A
TI
N
G
CAP
A
CI
TY
(M
B
H
)
TB
D
S
ee N
ot
e 6.
M
ini
m
um
Legs
@
60 C
F
M
/Leg
TB
D
See
N
ot
e 6.
TB
D
S
ee N
ot
e 6.
A
H
B6
0
+
R9
8
L
Si(
e
)/
A
S
M
E
A
IRFLOW
(
C
FM
)
TA
P
4
(M
L)
2.
0
NE
T
HE
A
TI
N
G
CAP
A
CI
TY
(M
B
H
)
TB
D
S
ee N
ot
e 6.
TB
D
See
N
ot
e 6.
TB
D
S
ee N
ot
e 6.
A
H
B6
0
+
R9
8
L
Si(
e
)/
A
S
M
E
A
IRFLOW
(
C
FM
)
TA
P
5
(L
)
1.
5
NE
T
HE
A
TI
N
G
CAP
A
CI
TY
(M
B
H
)
TB
D
S
ee N
ot
e 6.
N
um
ber
of
3"
di
am
et
er
br
an
ch
le
gs
appl
ic
abl
e t
o
H
ig
h
V
el
oc
ity
S
yst
em
s on
ly
.
U
ded o
nl
y i
f
m
et
hods ot
her
th
an
Tabl
e
3 i
s used t
o
det
er
m
ine du
ct
s
izes
.
M
ini
m
um
Legs
@
60 C
F
M
/Leg
O
pt
im
al
Legs
@
50
C
F
M
/L
eg
M
ax
im
um
Legs @
40 C
F
M
/Leg
O
pt
im
al
Legs
@
50
C
F
M
/L
eg
M
ax
im
um
Legs @
40 C
F
M
/Leg
M
ini
m
um
Legs
@
60 C
F
M
/Leg
O
pt
im
al
Legs
@
50
C
F
M
/L
eg
M
ax
im
um
Legs @
40 C
F
M
/Leg
M
ini
m
um
Legs
@
60 C
F
M
/Leg
O
pt
im
al
Legs
@
50
C
F
M
/L
eg
M
ax
im
um
Legs @
40 C
F
M
/Leg
TB
D
See
N
ot
e 6.
TB
D
S
ee N
ot
e 6.