Product Overview

MC120P POST PURGE CHASSIS

The MC120P Chassis provides the following capabilities:

— A fifteen (15) second post purge at the end of an operating cycle or after a safety shutdown

condition (prior to initiating a lockout).

— Remote reset in the event of a lockout condition.

Fifteen (15) second post purge — The blower motor (terminal 8) remains energized for at least 15

seconds at the end of every operating cycle (power removed from terminal 7). The blower motor also

remains energized for 15 seconds following a condition which causes a safety shutdown (de-energiz-

ing terminals 3, 4, and 5). After the 15 second post purge is completed, the MC120P will initiate the

safety lockout - energizing the alarm relay (lockout pushbutton) and terminal A.

Note: Refer to Figures 6, 7, 8 and 9 on pages 29 and 30 for wiring the MC120P chassis. The air flow

switch is wired between terminals 7 and 6. On the MC120, MC120R, MC230, and MC230R, the air

flow switch is wired between terminals 8 and 6.

Remote Reset - The MC120P chassis provides remote reset capability of a safety lockout. Refer to

“Remote Reset Chassis (MC120R, MC230R, MC120P) for an explanation of the wiring and opera-

tion of the remote reset function.

REMOTE RESET CHASSIS (MC120R, MC120P, MC230R)

The MC120R/MC120P/MC230R Chassis provides remote reset capabilities in the event of a lockout

condition. A blue slide switch located on the chassis (on the same PC board as the built-in reset

switch) determines the method of reset. The MC120R and MC230R can be reset in any of the fol-

lowing ways:

1. Depress and release the reset button built into the MC120R/MC120P/MC230R chassis. This

reset button will always reset the control, regardless of the position of the blue slide switch.

2. To reset the control via a remote pushbutton, move the blue slide switch towards the wiring base.

Wire a momentary dry contact pushbutton into the two (2) terminals located on the MC120R/

MC120P/MC230R chassis (on the same PC board as the built-in reset switch) and depress the

button for one (1) second. The maximum distance the remote reset switch can be wired from the

control is 1,000 feet (max. wire size #14).

3. To reset the control via a power interruption, move the blue slide switch away from the wiring

base (towards the dust cover). Interrupt the 120 VAC (MC120R/MC120P) or 230 VAC

(MC230R) line power to the MC120R/MC120P chassis for one (1) second. The lockout will be

reset when power is restored.

4. To reset via power interruption, remove 120 VAC (MC120R, MC120P) or 230VAC (MC230R)

line power on the indicated terminals for 1 second for the following controls:

Terminal 1 MP560, MP561, MP562 when used with any amplifier.

MP100, MP101, MP230, MP230H when used with MAUV1 or

MAUV1T amplifier modules.

Terminal 7 MP100, MP101, MP230, MP230H when used with MART1 or MART1T

amplifier modules.

CAUTION: Remote reset is recommended only on a control solely for proved ignition pro-

gramming (pilot ignited burner) or a control for use only with appliances in which unburned

fuel cannot accumulate and that is intended for installation in inaccessible locations such as

open-flame, ceiling-suspended gas heaters.