Install and Operating Manual Owner's manual

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Installation and Operation Instructions Document 4206

The MC Extension Box (MCX) increases the

number of stages a Laars Modulating Control (MC)

can control from 4 to 12. All logic, memory, and

control algorithms reside in the MC panel. The MC

panel directly controls four built-in stages. When an

MCX is connected to the MC, the MC will

automatically recognize eight additional stages. Any

of the twelve stages can be the lead stage and

automatic rotation provides even wear among all

active stages.

The MCX can be equipped with up to four

output cards, each of which controls a pair of stages.

There are two types of output cards: 135Ω cards

control up to two fully modulating 135Ω stages, and

Current/Voltage cards can be programmed to control

two 0-5V, 1-5V, 0-10V, 2-10V, or 4-20mA stages. To

select the type of output for Current/Voltage cards,

follow the directions in the MC I/O Manual (System

Startup, Selecting the Output Type).

Installation and Operation

Instructions for

MC Extension Box

Providing up to 12 Stages of Full Modulation Control

Each new stage must also be configured for its

Mode (Auto, Manual, Standby, On, and Off), Ignition

Start Point, and Modulation Start Point as described in

the MC I/O manual (Stage Settings). All other steps

and procedures to configure the MC presented in its I/

O manual must be completed to insure smooth

operation of a MC/MCX system.

SECTION 1.

Installation

1.1 Mounting the EXM

Select a location adjacent to the MC control and

within the reach of the provided Panel-to-Panel cable.

Remove the MCX panel from the metal

enclosure by removing the top center screw and

loosening the two bottom screws. Lift the panel out.

Screw the enclosure to the surface through the

mounting holes in the back of the enclosure.

J12

Card 4 Card 3 Card 2

Card 1

EXTENSION MODULE

REAR VIEW

Fuse

Connection to

Mount Output

Card 4 here to

control Stages

K and L

Output Cards are ordered

separately as required

Mount Output

Card 3 here to

control Stages

IandJ

Mount Output

Card 2 here to

control Stages

GandH

Mount Output

Card here to

control Stages

EandF

Mounting Holes

Figure 1. MCX Rear View.

Figure 2. Mounting Holes.

Summary of content (4 pages)

PAGE 1
Installation and Operation Instructions Document 4206 Installation and Operation Instructions for MC Extension Box Providing up to 12 Stages of Full Modulation Control The MC Extension Box (MCX) increases the number of stages a Laars Modulating Control (MC) can control from 4 to 12. All logic, memory, and control algorithms reside in the MC panel. The MC panel directly controls four built-in stages. When an MCX is connected to the MC, the MC will automatically recognize eight additional stages.
PAGE 2
LAARS HEATING SYSTEMS Page 2 1.2 Mounting the Output Cards The Output Cards are mounted on the rear of the MCX (see Figure 1). Each Output Card controls two stages. The two stages connected to one Output Card must have the same type of output (135Ω, 0-5V, 1-5V, 0-10V, 210V, or 4-20mA). However, different types of Output Cards can be combined on the MCX, and each Output Card can be programmed differently.
PAGE 3
MC Extension Box Page 3 Limit Circuit 1 2 3 4 E F Typical for each stage Figure 6. Stage Wiring. Class 1 voltages must enter the enclosure through a different opening from any Class 2 voltage wiring. C1 C2 C3 B R W 135W C4 B C5 R W 135W E B B R W B C8 C9 C10 C11 C12 R W 135W F 135 W Motor C1 C6 C7 B R W 135W G R W B 135 W Motor H R W B 135 W Motor C2 C3 C4 C5 C6 C7 + 24 + 24 NC R W 135 W Motor C8 C9 C10 C11 C12 Ω Modulating Motors 1.
PAGE 4
135W Current Common Increase Mod Decrease Mod Stage E C2 C3 C1 C1 Stage F C5 C6 C4 Stage G C8 C9 Stage H C11 Stage I Voltage Signal 24V Sink (GND) Source (+) V+ GND C2 C3 C1 C4 C5 C6 C4 C7 C7 C8 C9 C7 C12 C10 C10 C11 C12 C10 C14 C15 C13 C13 C14 C15 C13 Stage J C17 C18 C16 C16 C17 C18 C16 Stage K C20 C21 C19 C19 C20 C21 C19 Stage L C23 C24 C22 C22 C23 C24 C22 Table 1.