heat-timer Mini-MOD-CNC User manual

HT# 059102-00 B




ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
Extension Module
Full Modulation Sequencing Extension
F
H
J
Power
CAUTION: Risk of Electric Shock.
More than one disconnect switch may be required
to de-energize the equipment before servicing.
PWR
L N
1 2
E
3 4
F
5 6
G
7 8
H
9 10
I
11 12
EXTENSION
MODULE
RS-485
Ext A
INPUT RATINGS:
115VAC 60Hz, 12VA MAX
Use Copper Conductors Only.
OUTPUT RATINGS:
120VAC, 6A RESISTIVE
1A PILOT DUTY, 15A TOTAL
FOR ALL CIRCUITS
E
G
I
Comm
Ext B
K
M
O
L
N
P
1716
VLTmA
CUR / VLT
201916
VLTmAGND
CUR / VLT
232219
VLTmAGND
CUR / VLT
262522
VLTmAGND
CUR / VLT
J
13 14
K M OL N P
E F G H
K ML N
15
GND
18
GND
21
GND
24
GND
2928
VLTmA
CUR / VLT
323116
VLTmAGND
CUR / VLT
27
GND
30
GND
I J
O P
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
FOR ALL CIRCUITS
120VAC, 6A RESISTIVE
OUTPUT RATINGS:
1A PILOT DUTY, 15A TOTAL
115VAC 60Hz , 12VA MAX
INPUT RATINGS:
USE COPPER CONDUCTORS ONLY
CAUTION: RISK OF ELECTRIC SHOCK
More than one disconnect switch may be required
to de-energize the equipment before servicing.
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
SYSTEM
A
B
C
D
Condensing / Non-Condensing Control
RUNPROGRAM
12 13 15
14 17
16 18 22
20
19 21 24
23
-+
+
mA
GND VLT
CUR / VLT
A
-+
+
mA
GND VLT
-+
+
mA
GND VLT
-+
+
mA
GND VLT
+
mA
CUR / VLT
B
CUR / VLT
C
CUR / VLT
D
OD=25oF SYS= 145oF
<<A>> B <C> D
100% 52% --- ---
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
29 25 27
26 28 32
30 31
TT
OO
TEMP
OUTDOOR
OO
TEMP
SYSTEM
PROVE
/DHW
SHUTDOWN
/TSTAT
/SETBACK
12345678910 11
LN
RS-485
SYS ABCD
PWR
EXTENSION
MODULE
Mini-MOD-CNC







2 Heat-Timer Corp.

 . . . . . . . . . . . 3
 . . . . . . . . . . . . .4
 . . . . . . . . . . . . . 5
Features . . . . . . . . . . . . . . . . . . . . .6
Outdoor Reset Concept . . . . . . . . . . . . . 7
Reset Ratio/Outdoor Reset . . . . . . . . . . . . 7
Make Sure You Have the Right Control . . . . .8
 . . . . . . . . . . . . . . . . . . .8
Selecting the System Features. . . . . . . . . . 8
 . . . . . . . . . . . . . . . . . . . . 9
Mounting the Enclosure . . . . . . . . . . . . . 9
Install the Sensors . . . . . . . . . . . . . . . 10
System Sensor (HSS) Installation . . . . . . . . 10
Outdoor Sensor Installation . . . . . . . . . . . 10
Wiring . . . . . . . . . . . . . . . . . . . . . 11
Wiring the Power. . . . . . . . . . . . . . . . 11
Wiring the Sensors . . . . . . . . . . . . . . . 11
Wiring the Shutdown, Tstat, or Setback . . . . . 11
Wiring the Prove . . . . . . . . . . . . . . . . 12
Wiring the Domestic Hot Water (DHW) Call . . . 12
Wiring the System Output . . . . . . . . . . . 12
Wiring the Boilers . . . . . . . . . . . . . . . 13
Wiring Multi-Stage Boiler Outputs . . . . . . . . 13
Wiring to Modulating Output . . . . . . . . . . 13
Connecting to the Mini-Extension Panels . . . . 14
Connecting to the 4-20mA EMS Interface . . . . 14
 . . . . . . . . . . . 15
Startup Settings . . . . . . . . . . . . . . . . 16
Program Change Switch Setting . . . . . . . . 16
Startup Sequence . . . . . . . . . . . . . . . 16
Sensor Type . . . . . . . . . . . . . . . . . . 16
Switch Set Point . . . . . . . . . . . . . . . . 16
Switch Differential . . . . . . . . . . . . . . . 17
Switch Delay. . . . . . . . . . . . . . . . . . 17
Heavy Load Sequence 2nd Group . . . . . . . 17
Condensing Boiler Type . . . . . . . . . . . . 17
Condensing and Non-Condensing Boiler Number 17
Modulating Boiler Settings . . . . . . . . . . . 18
Modulating Output Type . . . . . . . . . . . . 18
Modulating Mode. . . . . . . . . . . . . . . . 18
Sequencing Boiler Settings . . . . . . . . . . 19
Sequencing Output Type . . . . . . . . . . . . 19
Staging Mode . . . . . . . . . . . . . . . . . 19
Prove/Domestic Hot Water (DHW) Priority . . . . 19
Domestic Hot Water Set Point . . . . . . . . . 19
Shutdown/Tstat/Setback Mode . . . . . . . . . 19
Boost Mode . . . . . . . . . . . . . . . . . . 20
Sensor Fault . . . . . . . . . . . . . . . . . . 20
Setting the Control to Factory Defaults. . . . . 20
 . . . . . . . . . 21
Operating Settings . . . . . . . . . . . . . . . 22
Program Change Switch Setting . . . . . . . . 22
Season . . . . . . . . . . . . . . . . . . . . 22
Reset Ratio . . . . . . . . . . . . . . . . . . 22
Offset . . . . . . . . . . . . . . . . . . . . . 22
Outdoor Cutoff Temperature . . . . . . . . . . 23
Minimum Water Temp . . . . . . . . . . . . . 23
Maximum Water Temp . . . . . . . . . . . . . 23
System Settings . . . . . . . . . . . . . . . . 24
Setback . . . . . . . . . . . . . . . . . . . . 24
Purge Delay . . . . . . . . . . . . . . . . . . 24
System Run-On . . . . . . . . . . . . . . . . 24
Lead Boiler Rotation . . . . . . . . . . . . . . 25
Standby Time . . . . . . . . . . . . . . . . . 25
Last Stage Hold . . . . . . . . . . . . . . . . 25
Lead Stages . . . . . . . . . . . . . . . . . . 25
Operating Modulating Boiler Settings . . . . . 26
Gain. . . . . . . . . . . . . . . . . . . . . . 26
Lag Delay . . . . . . . . . . . . . . . . . . . 26
Soft-Off Delay . . . . . . . . . . . . . . . . . 26
Operating Staging Boiler Settings . . . . . . . 27
Reaction Time . . . . . . . . . . . . . . . . . 27
Minimum Runtime . . . . . . . . . . . . . . . 27
Day / Night Schedule. . . . . . . . . . . . . . 28
Set Time. . . . . . . . . . . . . . . . . . . . 28
History . . . . . . . . . . . . . . . . . . . . . 28
Maintenance . . . . . . . . . . . . . . . . . . 28
System & Outdoor Sensor Trim . . . . . . . . . 29
Output Modulation Trim. . . . . . . . . . . . . 29
Conguration . . . . . . . . . . . . . . . . . 29
Display . . . . . . . . . . . . . . . . . . . . 30
Boiler Status . . . . . . . . . . . . . . . . . . 30
Display Sequencing Boiler Status . . . . . . . . 30
Display Messages . . . . . . . . . . . . . . . 30
Boiler Stage Settings . . . . . . . . . . . . . . 31
Mode . . . . . . . . . . . . . . . . . . . . . 31
Ignition % . . . . . . . . . . . . . . . . . . . 32
Modulation Start % . . . . . . . . . . . . . . . 32
Copy Settings - Boiler A Only . . . . . . . . . . 32
. . . . . . . . . . . . . . . . 33
 . . . . . . . 34
 . . . . . . . 35
 . . . . . . . . . . . . . . . . . . . . 36
 . . . . . . . . . . . . . . . . . . . . . . 37
 . . . . . . . . . . . . . . . . . 40
HT# 059102-00 B

Mini-MOD-CNC & Mini-Extension Installation Manual 3

In response to new advancement in condensing boiler design and size, many applications utilize multiple condensing boilers in
addition to the non-condensing boilers. That triggered Heat-Timer's patent design of the Mini-MOD-CNC . It is intended to manage
the two groups of boilers to maximize system efciency at the lowest operating cost while maintaining the desired comfort. The
Mini-MOD-CNC operates each group based on the Target temperature switching set point.
Depending on the actual Target Temperature, the Mini-MOD-CNC will determine which group of boilers will be the lead and which
group will be the lag group. The Condensing Group of boilers will be the Lead group when the Target Temperature is below the
Switching Set Point. However, when the Target Temperature rises above the Switching Set Point, the Non-Condensing Boiler Group
will be the lead group and the Condensing Group will be the lag group.
Basically, the Mini-MOD-CNC will allow the condensing group of boilers to operate as along as the Target Temperature is below the
Switching Set Point. See "Switch Set Point" on page 16. During that period, if additional output boilers are needed, the Mini-MOD-
CNC will energize the non-condensing boilers to meet the load. See "Heavy Load Sequence 2nd Group" on page 17. When less output
is required the Mini-MOD-CNC will de-energize the non-condensing boilers prior to de-energizing the condensing boilers.
Above the Switch Set Point
Non-Condensing are the Lead Group
Condensing are the Lag Group
Target Switch
Set Point = 120°F
Below the Switch Set Point
Condensing are the Lead Group
Non-Condensing are the Lag Group
120°F
140°F
100°F
SWITCH MODE = Target Temperature
SYSTEM
A
B
C
D
Condensing / Non-Condensing Control
12
RUNPROGRAM
FOR ALL CIRCUITS
120VAC, 6A RESISTIVE
OUTPUT RATINGS:
1A PILOT DUTY, 15A TOTAL
115VAC 60Hz , 12VA MAX
INPUT RATINGS:
USE COPPER CONDUCTORS ONLY
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
34567 8 910 1112 13 15
14 17
16 18 22
20
19 21 24
23 29
25 27
26 28 32
30 31
LN
-+
+
TT
OORS-485
mAGND VLT
SYS ABCD
PWR
CUR / VLT
A
-+
+
mAGND VLT
-+
+
mA
GND VLT
-+
+
mA
GND VLT
+
mA
TEMP
OUTDOOR
OO
TEMP
SYSTEM
EXTENSION
MODULE
CUR / VLT
B
CUR / VLT
C
CUR / VLT
D
CAUTION: RISK OF ELECTRIC SHOCK
More than one disconnect switch may be required
to de-energize the equipment before servicing.
PROVE
/DHW
SHUTDOWN
/TSTAT
/SETBACK
OD=25oF SYS= 145oF
<<A>> B
100% 52%
CONDCOND
NON-
COND
NON-
COND
NON-
COND
NON-
COND
CONDCOND
SYSTEM
A
B
C
D
Condensing / Non-Condensing Control
12
RUNPROGRAM
FOR ALL CIRCUITS
120VAC, 6A RESISTIVE
OUTPUT RATINGS:
1A PILOT DUTY, 15A TOTAL
115VAC 60Hz , 12VA MAX
INPUT RATINGS:
USE COPPER CONDUCTORS ONLY
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
34567 8 910 1112 13 15
14 17
16 18 22
20
19 21 24
23 29
25 27
26 28 32
30 31
LN
-+
+
TT
OORS-485
mAGND VLT
SYS ABCD
PWR
CUR / VLT
A
-+
+
mAGND VLT
-+
+
mA
GND VLT
-+
+
mA
GND VLT
+
mA
TEMP
OUTDOOR
OO
TEMP
SYSTEM
EXTENSION
MODULE
CUR / VLT
B
CUR / VLT
C
CUR / VLT
D
CAUTION: RISK OF ELECTRIC SHOCK
More than one disconnect switch may be required
to de-energize the equipment before servicing.
PROVE
/DHW
SHUTDOWN
/TSTAT
/SETBACK
OD=25oF SYS= 145oF
<<A>> B
100% 52%
Target
Temp
Above the Switch Set Point
Condensing are the Lead Group
Non-Condensing are the Lag Group
Outdoor Switch
Set Point = 30°F
Below the Switch Set Point
Non-Condensing are the Lead Group
Condensing are the Lag Group
30°F
50°F
10°F
SWITCH MODE = Outdoor Temperature
CONDCOND
NON-
COND
NON-
COND
NON-
COND
NON-
COND
CONDCOND
SYSTEM
A
B
C
D
Condensing / Non-Condensing Control
12
RUNPROGRAM
FOR ALL CIRCUITS
120VAC, 6A RESISTIVE
OUTPUT RATINGS:
1A PILOT DUTY, 15A TOTAL
115VAC 60Hz , 12VA MAX
INPUT RATINGS:
USE COPPER CONDUCTORS ONLY
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
34567 8 910 1112 13 15
14 17
16 18 22
20
19 21 24
23 29
25 27
26 28 32
30 31
LN
-+
+
TT
OORS-485
mAGND VLT
SYS ABCD
PWR
CUR / VLT
A
-+
+
mAGND VLT
-+
+
mA
GND VLT
-+
+
mA
GND VLT
+
mA
TEMP
OUTDOOR
OO
TEMP
SYSTEM
EXTENSION
MODULE
CUR / VLT
B
CUR / VLT
C
CUR / VLT
D
CAUTION: RISK OF ELECTRIC SHOCK
More than one disconnect switch may be required
to de-energize the equipment before servicing.
PROVE
/DHW
SHUTDOWN
/TSTAT
/SETBACK
OD=25oF SYS= 145oF
<<A>> B
100% 52%
SYSTEM
A
B
C
D
Condensing / Non-Condensing Control
12
RUNPROGRAM
FOR ALL CIRCUITS
120VAC, 6A RESISTIVE
OUTPUT RATINGS:
1A PILOT DUTY, 15A TOTAL
115VAC 60Hz , 12VA MAX
INPUT RATINGS:
USE COPPER CONDUCTORS ONLY
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
34567 8 910 1112 13 15
14 17
16 18 22
20
19 21 24
23 29
25 27
26 28 32
30 31
LN
-+
+
TT
OORS-485
mAGND VLT
SYS ABCD
PWR
CUR / VLT
A
-+
+
mAGND VLT
-+
+
mA
GND VLT
-+
+
mA
GND VLT
+
mA
TEMP
OUTDOOR
OO
TEMP
SYSTEM
EXTENSION
MODULE
CUR / VLT
B
CUR / VLT
C
CUR / VLT
D
CAUTION: RISK OF ELECTRIC SHOCK
More than one disconnect switch may be required
to de-energize the equipment before servicing.
PROVE
/DHW
SHUTDOWN
/TSTAT
/SETBACK
OD=25oF SYS= 145oF
<<A>> B
100% 52%
Outdoor
Temp
HT# 059102-00 B

4 Heat-Timer Corp.

HT# 059102-00 B
FOR ALL CIRCUITS
120VAC, 6A RESISTIVE
OUTPUT RATINGS:
1A PILOT DUTY, 15A TOTAL
115VAC 60Hz , 12VA MAX
INPUT RATINGS:
USE COPPER CONDUCTORS ONLY
CAUTION: RISK OF ELECTRIC SHOCK
More than one disconnect switch may be required
to de-energize the equipment before servicing.
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
SYSTEM
A
B
C
D
Condensing / Non-Condensing Control
RUNPROGRAM
12 13 15
14 17
16 18 22
20
19 21 24
23
-+
+
mA
GND VLT
CUR / VLT
A
-+
+
mA
GND VLT
-+
+
mA
GND VLT
-+
+
mA
GND VLT
+
mA
CUR / VLT
B
CUR / VLT
C
CUR / VLT
D
OD=25oF SYS= 145oF
<<A>> B <C> D
100% 52% --- ---
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
29 25 27
26 28 32
30 31
TT
OO
TEMP
OUTDOOR
OO
TEMP
SYSTEM
PROVE
/DHW
SHUTDOWN
/TSTAT
/SETBACK
12345678910 11
LN
RS-485
SYS ABCD
PWR
EXTENSION
MODULE
Mini-MOD-CNC
The digital display shows the System and Outdoor temperatures,
the lead stage and lead group <<in brackets>>, and the status of
each stage. To view and adjust settings, press the appropriate buttons.
120VAC Power
Four N.O. Boiler startup relay
outputs. Each is wired in series
with each boiler's limit circuit.
System Output controls
pumps, valves, or other
system components.
Four modulation outputs can be 0-5V,
0-10V, 1-5V, 2-10V, or 4-20ma. Go to
Startup Menu to determine the type of
output for each stage.
LED indicates the
associated relay status.
Button functions are presented on
Bottom Row of display.
When connecting Outdoor and System
Sensors, no Polarity is observed.
Prove terminals must be connected for
the Mini-Mod-CNC to operate the boilers.
Connect Extension panels to
add additional stages using
a phone style cable (cable
provided with Mini-Extension).
Program Switch to restrict access to
function changes. This switch is
covered with the Wiring Enclosure.

Mini-MOD-CNC & Mini-Extension Installation Manual 5

HT# 059102-00 B
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
Extension Module
Full Modulation Sequencing Extension
F
H
J
Power
CAUTION: Risk of Electric Shock.
More than one disconnect switch may be required
to de-energize the equipment before servicing.
PWR
L N
1 2
E
3 4
F
5 6
G
7 8
H
9 10
I
11 12
EXTENSION
MODULE
RS-485
Ext A
INPUT RATINGS:
115VAC 60Hz, 12VA MAX
Use Copper Conductors Only.
OUTPUT RATINGS:
120VAC, 6A RESISTIVE
1A PILOT DUTY, 15A TOTAL
FOR ALL CIRCUITS
E
G
I
Comm
Ext B
K
M
O
L
N
P
1716
VLTmA
CUR / VLT
201916
VLTmAGND
CUR / VLT
232219
VLTmAGND
CUR / VLT
262522
VLTmAGND
CUR / VLT
J
13 14
K M OL N P
E F G H
K ML N
15
GND
18
GND
21
GND
24
GND
2928
VLTmA
CUR / VLT
323116
VLTmAGND
CUR / VLT
27
GND
30
GND
I J
O P
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
120VAC Power
Six N.O. Boiler startup relay
outputs. Each is wired in series
with the boiler's limit circuit.
Six modulating outputs can be 0-5V,
0-10V, 1-5V, 2-10V, or 4-20ma. Go to
Mini-MOD or Mini-MOD-CNC Startup Menu
to determine the type of output for each stage.
LED indicates the
associated relay status.
Connect to Mini-MOD or Mini-MOD-CNC
and additional Extension panels to add
additional stages using phone style cable
(cable provided with Mini-Extension).
Extension Selection Switch to determine
Stage letters and LED colors.
Ext-A Stages E - J and all LEDs are Green
Ext-B Stages K - P and all LEDs are Red
This switch is covered with the Wiring Enclosure.

6 Heat-Timer Corp.


The Mini-MOD-CNC can operate both modulating and staging boilers. Just specify each of the Condensing and Non-Condensing Boiler
Group type and the Mini-MOD-CNC will activate the groups based on an adjustable set of criteria.

The Mini-MOD-CNC's control algorithms allow it to look at the rate of change in the system. If the system temperature is changing
quickly, the Mini-MOD-CNC will react quickly to adjust the modulating stages’ output. If the system temperature changes slowly, the
Mini-MOD-CNC will make slow and gradual output adjustments. Therefore, the Mini-MOD-CNC adapts to specic system requirements
and minimizes uctuations around the set point.

Whenever any of the Condensing or Non-Condensing Boiler Group type is set to Modulating, the Mini-MOD-CNC will accurately control
the output from 0 to 100% of modulation for each of these different types of motors. Moreover, a single Mini-MOD-CNC can control
multiple modulating burners each with a different modulating signal.

Whenever one of the Condensing or Non-Condensing Boiler Group Type is set to Staging, the Mini-MOD-CNC will accurately sequence
the stages using a PID logic. The sequencing group will have a set of adjustable parameters to help achieve better operation.

The Mini-MOD-CNC’s alphanumeric digital display names each system parameter in simple English and shows its precise value. The
easy to follow menu system allows users to quickly make changes to any system setting without having to learn any specialized codes
or keyboard commands.

Rotating the lead stage of each group promotes even wear. The Mini-MOD-CNC has three modes of rotation: Manual, Last On, or Time.
The Time rotates the lead stage every selected time period from every hour to every 60 days.

The Mini-MOD-CNC has a hydronic outdoor temperature reset function. This allows the Mini-MOD-CNC to change the set point
based on outdoor temperature. Furthermore, additional settings have been added to ne tune this operation, like Offset, Minimum, and
Maximum Water Temperature and night setback schedule.

This output can be used to activate a system pump, combustion air damper, or perform any other function that is required when any stage
is active. It will energize whenever the outdoor temperature is below the Outdoor Cutoff setting. A System Prove input checks the status
of components activated by the System output before stages can be activated.

The Mini-MOD-CNC can stage modulating boilers as needed. In Normal Modulation, it will allow the modulation to increase on the lead
boiler until it reaches its modulation start point adjustment. Then, the Mini-MOD-CNC will start the next boiler and so on. Moreover,
the Mini-MOD-CNC allows for a parallel mode that can modulate several boilers together as a one large boiler. This mode is useful when
used with condensing boilers as they run more efcient at lower modulation. Thus, it is better to run several boilers at lower modulation
than to run a single boiler at full re.

As a stand-alone, the Mini-MOD-CNC is designed to control four stages. However, it has the capability of expanding its control to two
extension panels (HT# 926712-00) each with six boiler stages. Thus, the Mini-MOD-CNC can control a total of up to 16 boiler stages.
HT# 059102-00 B

Mini-MOD-CNC & Mini-Extension Installation Manual 7

The Mini-MOD-CNC has multiple operating modes that satisfy most hydronic systems.
It changes the System Set Point based on outdoor temperature (Outdoor Reset). The
Mini-MOD-CNC varies the temperature of the circulating heating water in response to
changes in the outdoor temperature. The heating water temperature is controlled through the
modulation or sequencing of the stages.
The Mini-MOD-CNC also controls the system circulating pump with an adjustable Outdoor
Cutoff. When the outdoor temperature is above the Outdoor Cutoff, the pump is off and no
heating water is circulated through the system. When the outdoor temperature drops below
the Outdoor Cutoff, the system pump relay is activated and the heating water circulates
through the system. The temperature of the heating water is controlled by the Reset Ratio,
Water Offset, and changes with Outdoor temperature.

When a building is being heated, heat escapes through the walls, doors, and windows to
the colder outside air. The colder the outside temperature, the more heat escapes. If you
can input heat into the building at the same rate that it is lost out of the building, then the
building temperatures will remain constant. The Reset Ratio is an adjustment that
lets you achieve this equilibrium between heat input and heat loss.
The starting point for most systems is the 1.00 (OD):1.00 (SYS) (Outdoor
Temperature : Heating Water Temperature) ratio. This means that for every
degree the outdoor temperature drops, the temperature of the heating water will
increase one degree. The starting point of the curve is adjustable, but comes
factory selected at 70°F Outdoor Temp. and 100°F Water Temp. For example with
a 1.00 (OD):1.00 (SYS) ratio, if the outdoor temperature is 50°F, this means the
temperature has fallen 20° from the starting point of 70°F. Therefore, the heating
water temperature will increase 20° to 120°F.
Each building has different heat loss characteristics. A very well insulated
building will not lose much heat to the outside air, and may need a Reset Ratio
of 2.00 (OD):1.00 (SYS) (Outdoor:Water). This means the outdoor temperature
would have to drop 2 degrees to increase the water temperature 1 degree. On
the other hand, a poorly insulated building with insufcient radiation may need
a Reset Ratio of 1.00 (OD):2.00 (SYS). This means that for each degree the
outdoor temperature dropped the water temperature will increase 2 degrees. The
Mini-MOD-CNC has a full range of Reset Ratios to match any buildings heat loss
characteristics.
A heating curve that relies not only on Outdoor temperature but also on the type of
radiation will improve heat comfort. The following are suggested initial settings
for different types of radiation based on average building insulation and heat loss.
The contractor can ne tune these adjustments based on the specic building need.
  
Radiators (Steel & Cast Iron) 1.00 (OD) : 1.00 (SYS) 0˚F
Baseboard (Finned copper tube& Cast Iron) 1.00 (OD) : 1.00 (SYS) 0˚F
Radiant (High Mass/Concrete) 4.00 (OD) : 1.00 (SYS) -10˚F
Radiant (Low Mass/Joists) 2.00 (OD) : 1.00 (SYS) -10˚F
Fan Coils & Air Handlers 1.00 (OD) : 1.00 (SYS) 20˚F
Outdoor Temperature
Water Temperature
70 405060
130
120
110
100
Outdoor Temperature
Water Temperature
70 405060
110
100
90
80
Outdoor Temperature
Water Temperature
70 405060
150
140
130
120
1:4
With a 0° Offset, the
Reset curves begin at
100° Water Temperature.
With a -20° Offset, the
Reset curves begin at
80° Water Temperature.
With a +20° Offset, the
Reset curves begin at
120° Water Temperature.
1:4
1:4 1:1
1:1
1:1
4:1
4:1
4:1
90
100
+20 Offset
-20 Offset
Outdoor Temperature
Water Temperature
70 405060
130
120
110
100
1:4 1:1
4:1
Colder
Warmer
Outdoor Temperature (in °F)
70 60 50 40 20
30 0 -10
10 -20
100
120
110
130
140
150
160
180
170
190
200
210
220
1:3 1:2 1:1.5
1:1.25
1:1
1.25:1
1.5:1
2:1
3:1
4:1
Water Temperature (in °F)
Reset Ratio Curves
Reset Ratio is Presented as
Outdoor Temp. : Water Temp. Ratio
1:4
HT# 059102-00 B

8 Heat-Timer Corp.

If you need the Mini-MOD-CNC to do additional tasks that either are not listed or do not know how to congure them, contact Heat-
Timer Corp. Sales Department either by Phone [phone], Fax [phone], or by E-mail [e-mail].

Setting an Initial Program will ease the conguration of the Mini-MOD-CNC and will give the opportunity to utilize many of the energy
saving features and give more comfortable heat when needed.
The program should consist of the following:
• Selecting the features that your system can utilize.
• Installation: Install the Control, switches and sensors. See "Installation" on page 9
• Setting the System Startup. See "Startup Settings" on page 16
• Setting the System Operating Settings. See "Operating Settings" on page 22
• Setting the Stages. See "Operating Modulating Boiler Settings" on page 26 and "Operating Staging Boiler Settings" on page 27
• Adjusting Reset Ratio and Water Offset (In Reset Mode Only). See "Reset Ratio" on page 22

The Mini-MOD-CNC has been designed with Hydronic building heating, using both condensing and non-condensing boilers, as the
primary purpose. With this in mind, many of the Mini-MOD-CNC features can be utilized to ease, enhance, and improve your system
performance. Some of these features are listed in this section.

• The Mini-MOD-CNC can be congured to control up to 4 condensing and non-condensing boilers. It can control up to 16 boiler
stages using a maximum of two Mini-Extension Panels (HT# 926712-00).

• The Mini-MOD-CNC can stage modulating boilers using one of two methods. Normal Modulation Mode, allows it to increase the
modulation of the lead boiler. When the lead boiler reaches its Modulation Start point adjustment and does not satisfy the load, the
Mini-MOD-CNC will start the next boiler and so on. This mode targets boilers that can run more efcient at higher modulation rates.
• The Parallel Modulation Mode can modulate several boilers together as one large boiler. This mode is useful for boilers that are
more efcient at lower ring rate as in many condensing boilers.

• The Mini-MOD-CNC is designed to accurately control the modulation output from 0 to 100% for either current (4-20mA) or voltage
(0-5V, 0-1V, 1-5V, 2-10V) motors. A single Mini-MOD-CNC can control a combination of the above modulation motors.

• Rotating the rst burner to be activated on a call for output promotes even wear on all burners. The Mini-MOD-CNC has three modes
of rotation: Manual, Last-ON, or Time; automatically rotating every selected time period from every hour to every 60 days.

Two Setback modes are available for the Mini-MOD-CNC:
• The Day/Night Scheduling provides an adjustable time-based schedule for the Setback (only available when Shutdown or Tstat is
selected as the Setback/Shutdown Startup option). See "Shutdown/Tstat/Setback Mode" on page 19.
• The Setback mode uses an external signal to switch the operation of the Mini-MOD-CNC in and out of setback mode.

• This feature lets the Mini-MOD-CNC run the SYS relay for a longer period after the boilers have been turned off. When this relay is
used to control a pump, it helps in dissipating the excess heat from the boilers combustion chamber.
HT# 059102-00 B

Mini-MOD-CNC & Mini-Extension Installation Manual 9

Each of the Mini-MOD-CNC or Mini-Extension consists of three primary enclosure components.
• TheEnclosureDisplayModule: contains the display, buttons, LEDs and electric wiring terminals. It has two screws to hold it to
the base. A program conguration switch, used to adjust Mini-MOD-CNC settings, is placed above the terminals. This switch is
enclosed with the enclosure wiring cover for security. Wiring terminals are of the plug-in type to ease installation and removal.
• TheEnclosureBase: contains the holes to mount and hold the control against the wall or any at surface. All other enclosure
components mount on the base. The bottom section of the Enclosure Base contains the wiring chamber with knockouts on the
bottom to ease installation.
• TheEnclosureWiringCover: seals the wires from the external environment. It has two screws to hold it the base and a hole to
secure a lock on the wiring enclosure. A plastic web that separates the wiring chamber into high and low volt sections has been
provided.

• Select a location near the equipment to be controlled.
• The surface should be at and sufciently wide and strong to hold the Mini-MOD-CNC or the Mini-Extension.
• Keep the control away from extreme heat, cold, or humidity. Ambient operating temperature is from 20 to 120°F.
• Remove the Enclosure Wiring Cover from the control enclosure by removing the two bottom screws.
• Remove the Enclosure Display Module by removing the enclosure middle screws.
• Screw the Enclosure Base to the surface through the upper and lower mounting holes on the back of the enclosure.
• Replace the Enclosure Display Module and replace the enclosure middle screws.
• Do not replace the enclosure wiring cover until all wiring is done.
• When purchasing a padlock for the enclosure, the maximum shank diameter should not exceed ¼"
Enclosure Display Module
Enclosure Wiring Cover Enclosure Base
Hole for optional lock
(not supplied)
Mounting Holes
Display Mounting Screws
Wiring Cover
Mounting Screws
HT# 059102-00 B

10 Heat-Timer Corp.


• Only use a Standard Brass Tube sensor (HT #904250-00).
• The sensor wires can be extended up to 500' using a shielded 2-conductor cable
(Belden #8760 or equivalent). Do not ground the shield at the sensor but at the
panel using one of the terminals marked with an “O”.
• Do not run sensor wires in conduit with line voltage wiring.
• Install a 3/8"ID 1/2"NPT immersion well (HT #904011-00 or equivalent).
• Insert the sensor in a well approximately 10' feet past the last boiler on the
common supply header but before any major takeoffs.
• The sensor must be located where it sees the output of all the boiler stages. If
a boiler is piped so that the sensor does not see its output, the Mini-MOD-CNC
will not sequence the boilers correctly.
• The sensor can also be installed on the return to the boilers after all major returns
and before any boiler. However, when setting the reset ratio and the offset, the
user must consider the temperature drop across the building loop.
Immersion Well
3/8" ID 1/2" NPT
Heating System
Sensor
Common Supply Pipe
Sensor Probe
Immersion Heating System Sensor
Shield
Common Supply Pipe
Sensor Probe
Strap-On Heating System Sensor
Shield
Pipe Insulation
Connect
To control

If the System Sensor can not sense the
correct water temperature, the Mini-
MOD-CNC will not provide comfortable
heat levels.

• Only use the Heat-Timer sensor included with the unit (HT# 904220-00) .
• Locate the sensor in the shade on the north side of the building. The sensor
should never be in direct sunlight.
• Be sure the location is away from doors, windows, exhaust fans, vents, or other
possible heat sources.
• The sensor should be mounted approximately 10' feet above ground level.
• Adhere the Outdoor Label provided to the back of the sensor base.
• Use the Enclosure Base bottom knockout for the conduit. Use the locknut to hold
the conduit and enclosure base together. Screw the cover to the base.
• If screws are used to afx the enclosure to the wall, make sure to seal around the
sensor and wall except from the bottom.
• The sensor wires can be extended up to 500' using shielded 2-conductor cable
(#18/2). Do not ground the shield at the sensor but at the control using the
terminal marked with an “O”.
• Do not run sensor wires in conduit with line voltage wiring.




System Sensor
In Well
Shield
Not connected
Well Locknut
Sensor
in Well
Well
Sensor 2-Conductor
Shielded Cable
System
Strap-On
Sensor
Shield
Not connected
Plastic
Tie-Wraps
Around Pipe
Outdoor
Sensor
snap-in
location
Shield
not connected
Conduit
Outdoor Label
on back of Sensor
Outdoor Sensor
Strap-On Sensor
Immersion Sensor
Mounting
screws
location
Seal around
sensor and wall
Outdoor
drip-hole
HT# 059102-00 B