heat-timer MSI OTM Installation And Operation Manual page 8

8 MSI OTM Installation and Operation Manual
2. Connect the MSI Network wiring.
NOTE: MSI Network wires can be arranged in any way to the OTM. Multiple network sensors can also be daisy‐chained together
to the MSI Hub.
a. Run the 24Vac sensor wiring through a knockout on the OTM enclosure (note that it MUST be a different knockout than the
one through which the power wiring was run).
b. Connect the sensor wiring to terminal 6 (M+) and terminal 7 (M‐) on the OTM, and then to terminal 3 (M+) and terminal 4
(M‐) on the MSI Hub.
3. Connect the Alarm wiring.
NOTE: The OTM can be used to activate a Vis‐U‐Larm (925011‐00) when the tank level falls below the selected level.
a. Run the alarm wiring through a knockout on the OTM enclosure (note that it MUST be a different knockout than the one
through which the power wiring was run).
b. Connect the gray and white wire (alarm output connected to one Normally Open [N.O.] relay) to terminal 4 on the OTM.
NOTE: The N.O. contact is capable of switching 1 amp resistive at 120Vac.
c. Connect the red wire (alarm dry contacts) to terminal 5 on the OTM.
4. After all wiring to the OTM is complete, replace the OTM enclosure wiring cover and secure it in place with two screws.
059411-00 Rev. A
OTM MSI HUB
Heat‐Timer Corp.