Thermo Products omd-70 service manual C. Operating Modes

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All installations and services must be performed by qualified service personnel.

The control provides a 120 VAC output for an electronic air cleaner. This output is energized whenever the fan motor is energized (either low, heat or cool speed). Connection is made via male quick connect terminal labeled “EAC”.

Humidifier

The control provides a 120 VAC output for a humidifier. Connections are made to a male quick connect terminal labeled “FAN”. The control does not switch this output, it provides a pass-through connection from P1-7 from the switched primary voltage of the Burner Module.

Status LED

A red LED is provided to indicate any thermostat input has been recognized by the microprocessor on the control. See Diagnostic Features for a function description of operation.

Thermostat Input LEDs

Four green LEDs are placed beneath their respective thermostat connections (W, Y, G and DEHUM) and operate whenever a call is present. See Diagnostic Features for a function description of operation.

C. Operating Modes

Standby Mode

All outputs are off and the control is waiting for a thermostat demand. The thermostat inputs, and limit switch are continuously monitored. The control initiates action when a thermostat call is received or limit switch opens.

Fan Mode

A call for fan (“G”) is received from the thermostat. If no other mode is calling for blower operation, the control will operate the fan relay (K4) and power the “Low” blower speed terminal. The fan mode will be operated as long as the “G” input is calling and neither the Heat mode nor the Cool mode is calling for blower operation. When the Heat and Cool modes call for blower operation, their respective outputs will take precedence after their respective turn-on time delays have expired.

Heat Mode

When a call for heat (“W”) is received from the thermostat, if the “Cool” mode is not already active, the “T-T” terminal is energized and the blower on delay is started. The on-off pattern of DIP switch SW2 (positions 1 and 2) select one of four blower on delay values (see Table 11). When the delay time has elapsed, the “HEAT” blower speed is energized. The control remains in steady heat mode until the thermostat is satisfied. When the call for heat signal is removed, the “T-T” terminal is de-energized and the blower off delay is started. The on-off pattern of DIP switch SW2 (positions 3 and 4) select one of four blower off delay values (see Table 11). When the delay time has elapsed, the “HEAT” blower speed terminal is de-energized.

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Contents MODEL: OMD-70 INSTALLATION AND SERVICE MANUAL FOR YOUR SAFETYGAS-FIREDOR OIL-FIREDFURNACE DOWN FLOW & DIRECT VENT SEALED COMBUSTIONI. SAFETY SECTION If you do not follow these instructions exactly, a fire or explosion may result causing personal injury, loss of life or property damage Do not attempt to start the burner when All installations and services must be performed by qualified service personnel POWER SWITCH SECTION TABLE OF CONTENTSBEGINNING PAGE a. Combustible material b.Non-combustiblematerial MODELS OMD/GMDMODEL III. FURNACE SPECIFICATIONSGMD-85 BURNER DATA BLOWER DATAB. STANDARD CHIMNEY IV. INSTALLATION A. ROOF JACKC.FURNACE LOCATION D. BASE INSTALLATION Combustible Floor Base Model: 70-BASECottage Base Model: 01COT-BASE Figure 1A1. Combustible Floor Base Model: 70-BASE 2. Cottage Base Model: OMCCOT-BASE IMPORTANT: Adequate combustion air must be provided under all circumstances. If the underside of the home is skirted or enclosed e.g. by an enclosed crawlspace, the combustion air intake should exit through the side of cottage base and terminate outside of the structure. All joints and seams of supply ducts and combustion air ducts must be closed with a sealing method suitable to the application conditions and temperatures e.g. using high temperature silicone caulk and/or aluminum tape E. ALCOVE INSTALLATION F. CLOSET INSTALLATIONG. COMBUSTION AIR The preferred location of the outside combustion air intake termination e.g. an optional stainless steel intake hood, part no.370183 is through the side of the structure, skirting or enclosure. An alternate termination location is under the structure in the skirted or crawlspace area providing a minimum of 50 square inches of free area exists around the perimeter for outside combustion air to be drawn through. NOTE: Combustion air cannot be drawn from the occupied space of the home Figure H. FUEL PIPING 2. Oil Tank and Piping OMD-70 All installations and services must be performed by qualified service personnel Figure J. ELECTRICAL WIRING 1.Electrical Branch Supply Circuit 4. BLOWER CONTROLLER INFORMATION FOR PSC MOTOR TERMINAL DEFINITIONS & FIELD WIRINGA. Inputs B. OutputsC. Operating Modes PSC TROUBLE SHOOTING DIAGNOSTIC FEATURES5. WIRING DIAGRAM K. BURNER INSTALLATION L.BURNER OPERATION AND ADJUSTMENT replacement parts for location identification. After the furnace is warmed up to a steady- state condition about 15 minutes, the final burner adjustment should be made using combustion instrumentation for measuring carbon dioxide CO2 or oxygen O2, carbon monoxide CO, smoke for oil furnaces, and stack temperature. In order to achieve the most efficient combustion possible, the following steps must be taken M. FLUE GAS COMBUSTION ANALYSIS BURNER COMBUSTION PARAMETERSV. DEALER MAINTENANCE A. TROUBLESHOOTINGOMD/GMD TROUBLESHOOTING FLOWCHART Note: Check diagnostic code through view portprior to removing doors Are the thermostat wires closed? If 120 VAC is After fuel valve opens, does the burner ignite? Has the high limit thermostat B.CAD CELL CHECKOUT PROCEDURE: OMD ONLY C.HEAT EXCHANGER CLEANING INSTRUCTIONSD. CLEANING OR REPLACING FLUE PIPES E. EXTENDED SHUTDOWN VI. USER INFORMATION SECTION A. WARNINGS AND CAUTIONSB. COMPONENT LOCATIONS Figure C. INSPECTION AREASINSTALLATION / SERVICE D.FILTER LOCATION AND CLEANINGE. CONTACT INFORMATION APPENDIX A. REPLACEMENT PARTS LIST
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