LAARS Heating Systems
Page 56
7.K Ladder Diagrams (continued)
SPA
RE
(24VDC)
SAFETY
CHAI
N
20
00
R2
EN
CL
O
SU
R
E
FA
N
FA
N
120VAC
240VAC
120VAC
240VAC
BIC
FRO
M
BI
C
120VAC
OPTI
ONAL
OPTI
ONAL
OPTI
ONAL
H
IG
H
L
IM
IT
M
AN
U
AL
R
ES
ET
64
63
ALARM
BELL
62
60
59
58
61
57
O
ut
pu
t
An
al
og
0-10VDC
PU
M
P
3
24
V
19
24
N
15
12
0L
14
12
0N
7
GND
GND
6
5
CASCADE
GND
GND
RS485
BM
S
RS485
56
54
53
52
55
B
A
A
N
.C
.
N.
O
.
N
.C
.
N.
O
.
CO
NTACTS
R
U
N
R
EL
AY
ALARM
RELAY
CO
NTACTS
51
C
B
48
50
49
C
45
46
47
44
43
-
+
Po
wer
PU
M
P
L
O
ut
pu
ts
Co
ntacts
Se
nsor
In
pu
ts
Dry
In
pu
t
An
al
og
34
DHW
DHW
TT
-
2
TT
-
2
TT
-
1
TT
-
1
0-10VDC
BA
S
42
+
40
39
41
-
Heat
Deman
ds
37
38
35
36
N
L
26
O
U
TD
O
O
R
RETURN
SU
PPLY
SY
STEM
SY
STEM
DHW
29
30
27
28
32
31
33
DHW
SY
STEM
AU
XI
LIARY
PU
M
P
PU
M
P
AU
XI
LIARY
23
24
25
12
0N
GND
GND
24
V
24
V
24
V
24
N
24
N
24
N
12
0L
12
0L
12
0L
12
0N
12
0N
N
13
18
20
16
17
22
21
BO
ILER
4
3
10
11
9
8
12
GND
GND
1
2
1
TB1
2
PO
W
ER
S
U
PPLY
CO
NT
R
O
LLER
PO
W
ER
O2-3-4
O2-3-5
V-
V+
G
N
L
12VDC
TB
1-
GND
TB1-120N
TB1-120L
RS485
X22-12
X22-11
BIC
O2-3-4
O2-3-5
O2-1
O
2
SE
N
SO
R
O
2 C
O
N
TR
O
LL
ER
AIR
AC
TU
AT
O
R
FU
EL
AC
TU
AT
O
R
5
4
3
2
X54 -
FUEL
1
5
4
3
2
X53 -
AIR
1
X74-5
X74-4
WI
TH
TACHOM
ETER
TA
CH
TB1-120N
M
AI
N
G
AS
V
AL
VE
TB1-120N
M
AI
N
G
AS
V
AL
VE
X8-02-1
X10-05-1
X10-05-2
TB1-120N
X4-02-3
TB1-120N
X3-02-1
X5-02-3
X5-02-2
X5-01-3
X5-01-2
X3-02-1
X3-05-1
X5-03-1
X5-03-2
CO
NT
R
O
LLER
PO
W
ER
TB
1-
GND
TB1-120N
TB1-120L
HEAT
DEM
AND
FRO
M
BO
IL
ER
CO
NTRO
LLER
SAFETY
CHAI
N
I
S
SATI
SFI
ED
X5-03-4
X3-04-1
X3-04-2
X3-04-3
3
2
1
3
2
X4-19
X4-9
X21-1
X9-1
X3-04-4
X3-04-5
LMV BURNER CONTROLLER
TRAN
SM
ITTER
-
2
PR
ESSURE
H
IG
H
L
IM
IT
PR
ESSURE
TRAN
SM
ITTER
-
1
PR
ESSURE
1
X22-2
X22-1
(continued)
BIC
PR
ESSURE
CUT
O
UT
BOILER INTEGRATED CONTROLLER (BIC)
PO
W
ER
CO
NTR
O
LLER
TB1-120L
X10-1
X14-3
X14-10
TB1-27
TB1-28
X14-4
X14-11
TB1-29
TB1-30
X14-8
X14-1
TB1-24
TB1-23
X2-1
X2-8
TB1-47
TB1-48
X2-1
X2-8
TB1-45
TB1-46
X2-1
X2-8
TB1-43
TB1-44
TB1-120N
HEAT
DEM
ANDS
DHW
TT-2
TT-1
LM
V
X1-15
X1-13
X1-3
X1-2
X1-14
X1-1
X1-1
In
let
Se
nsor
Flue Se
nsor
20
k
10
k
Du
al
Elem
en
t
20
k
X1-1
10
k
IN
ST
AL
LED
FACTO
R
Y
Du
al
Elem
en
t
Se
nsor
O
utl
et
1
2
12
34
4
3
2
1
120VAC
(1P
H
/60Hz)
BL
O
W
ER
MO
TO
R
CO
NV
ENIENCE
O
U
TL
ET
ROD
FL
AM
E
PI
LO
T
VA
LVE
SP
AR
K
IG
N
IT
O
R
GENER
AT
O
R
SP
AR
K
(NO
T
INCLU
DED)
24VAC
TRANSFO
R
M
ER
X4-18
CO
NDENSATE
X4-8
X4-17
AU
TO
RESET
X4-7
X4-16
LO
W
GAS
X4-15
X4-6
HIGH
GAS
X4-14
X4-5
THERM
AL
X4-4
X4-13
X4-3
X4-12
LW
CO
X4-2
X4-11
FLO
W
X4-1
DHW
PU
M
P
DR
Y
CO
NTACT
DR
Y
CO
NTACT
SY
STEM
PU
MP
BO
ILER
PU
M
P
P
120VAC
TB1-120L
TB
1-
12
0N
TE
R
M
IN
AL
S
TR
IP
1
20
VA
C
TERMI
N
AL
STRI
P
24VAC
TB1-24N
TB1-24V
CB
24
VA
C
X10-3
VFD
CON
TAC
TOR
PO
W
ER
S
W
IT
CH
R2
CB
CB
A
O
N
O
FF
CB
4
1
X74-2
X74-3
2
5
M
1
VFD
PE
PE
U
V
W
L2
L1
L1
N
R2
H2398600-
LOGIC DIAGRAM
HTD 2.0, 120V
Figure 34. Model 2000, 120V Ladder Diagram
