43
110332-02 - 6/22
PHTM II
Installation, Operating & Service Instructions
12
Field Wiring
(continued)
From left to right, connections on terminal strip
are:
Terminal
Description
120 VAC L
Hot
120 VAC N
Neutral
Boiler Pump L
Hot
Boiler Pump N
Neutral
System Pump L
Hot
System Pump N
Neutral
Auxiliary Pump L
Hot
Auxiliary Pump N
Neutral
3. Pump outputs
A. Boiler Pump (supplied with boiler). Circulates
water through boiler. Boiler pump is always
on when boiler is responding to heating
demand. See Table 15-15 for alternate boiler
pump output functions. Maximum
recommended current draw for boiler pump is
2.0A.
B. System Pump: (field supplied) Circulates
water through radiation. System pump
is always on when boiler is responding
to heating demand. Refer to Table 15-15
for alternate system pump output functions.
Maximum recommended current draw for
system pump is 1.5A.
C. Auxiliary Pump: (field supplied) Auxiliary
pump output can be used for 2nd zone or
indirect pump. Refer to Table 15-15 for more
information and alternate auxiliary pump
output functions. Maximum recommended
current draw for auxiliary pump is 1.5A.
From left to right, connections on terminal strip
are:
Terminal
Description
Heat T'Stat 24 VAC thermostat (R - 24V "Hot")
Heat T'Stat 24 VAC thermostat
(W - Energized on Call for Heat)
Heat T'Stat 24 VAC thermostat (C - 24V Common)
Aux T'Stat
24 VAC thermostat (R - 24V "Hot")
Aux T'Stat
24 VAC thermostat
(W - Energized on Call for Heat)
External
Limit
Field supplied safety limit contacts (1)
External
Limit
Field supplied safety limit contacts (2)
0-10 V
4-20mA
Optional remote modulation control* (+)
0-10 V
4-20mA
Optional remote modulation control* (-)
Header
Sensor
Optional Header* Temperature Sensor (1)
Header
Sensor
Optional Header* Temperature Sensor (2)
Outdoor
Sensor
Optional Outdoor Temperature Sensor (1)
Outdoor
Sensor
Optional Outdoor Temperature Sensor (2)
*Available when Lead Lag Master Enabled.
Figure 12-2: 120 VAC Connections
Low Voltage Connections
Figure 12-3: Low Voltage Connections
1. All low voltage field connections to boiler are
made on Low Voltage Connections terminal strip
(see Figure 12-3) located on left side of bottom
panel. Route all low voltage wiring through
conduit knock out holes located on left side in
front of terminal strip.
Heat
T'stat
Aux
T'stat
Ext.
Limit
0-10V
4-20mA
Header
Sensor
Outdoor
Sensor
24 VAC
LWCO
Low Voltage Connections
R W C
R W
+
-
LWCO
(if needed)
24 Volt Heating
Thermostat
Auxilliary
Thermostat
External Limit
(if needed)
Wired
Connection
Header
Sensor
Outdoor
Sensor
A
B
A
B
1
2
1
2
REVISIONS
REV.
EN
DATE
DESCRIPTION
DWN
CHK
APVD
A
103-143-14599
1/6/2022
PRODUCTION RELEASE
EJL
UNLESS OTHERWISE NOTED:
ALL DIMENSIONS IN INCHES.
TOLERANCES:
X.X ±.1 X.XXX ±.005
X.XX ±.03 ANGLE ±1°
THIS DOCUMENT CONTAINS CONFIDENTIAL INFORMATION
AND ITS CONTENTS ARE THE SOLE PROPERTY OF U.S. BOILER
COMPANY, INC. ANY REPRODUCTION IN PART OR AS A
WHOLE WITHOUT THE WRITTEN PERMISSION OF U.S. BOILER
COMPANY, INC. IS STRICTLY PROHIBITED.
THIRD ANGLE
PROJECTION
MATERIAL:
ITEM NUMBER:
FIRST USE:
TITLE:
DRAWING NUMBER:
DATE:
REVISION:
SIZE: A
SHEET: 1 OF 1
SCALE: 1:1
APVD:
CHK:
DES: EJL
01/06/2022
ALTA
HEAT ONLY UNITS
LOW VOLTAGE CONNECTIONS
B
TS-103-77
120V
Line
Boiler
Pump
Aux
Pump
GND
L
N
L
N
L
N
L
N
System
Pump
L2
Power Supply
120/60/1
Overcurrent Protection/ Disconnect
Service Switch
L1
A
B
A
B
1
2
1
2
REVISIONS
REV.
EN
DATE
DESCRIPTION
DWN
CHK
APVD
A
103-143-14599
12/XX/2021
PRODUCTION RELEASE
EJL
UNLESS OTHERWISE NOTED:
ALL DIMENSIONS IN INCHES.
TOLERANCES:
X.X ±.1 X.XXX ±.005
X.XX ±.03 ANGLE ±1°
THIS DOCUMENT CONTAINS CONFIDENTIAL INFORMATION
AND ITS CONTENTS ARE THE SOLE PROPERTY OF U.S. BOILER
COMPANY, INC. ANY REPRODUCTION IN PART OR AS A
WHOLE WITHOUT THE WRITTEN PERMISSION OF U.S. BOILER
COMPANY, INC. IS STRICTLY PROHIBITED.
THIRD ANGLE
PROJECTION
MATERIAL:
ITEM NUMBER:
FIRST USE:
TITLE:
DRAWING NUMBER:
DATE:
REVISION:
SIZE: A
SHEET: 1 OF 1
SCALE: 1:1
APVD:
CHK:
DES: EJL
12/16/2021
ALTA
HEAT ONLY
120 VAC CONNECTIONS
A
TS-103-75
D. Maximum combined current draw for all
circulators is 5A.
