Thermo Products omd-70 service manual A. Inputs, B. Outputs

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

“C”	24 VAC common from transformer
“CC”	Compressor Contactor
“CC_COM”	Compressor Contactor Common
“LOW”	Continuous Blower Speed
“HEAT”	Blower heat speed tap
“COOL”	Blower cool speed tap

A. Inputs

Power supplies

Line voltage is applied between the “S1” and “N1” quick connect terminals. 24 VAC Class II Transformer secondary voltage supplied to X and C

Limit switch

The 120 VAC optically isolated limit switch input is connected on pin P2-1 & 9. Refer to the Heat Mode section for the control operation.

Thermostat call for heat “W”

24 VAC thermostat input. A call for heat is recognized when the thermostat connects “W” to “R”. This input has an indicator LED that will light when the control receives a call for heat. Refer to the Heat Mode section for the control operation.

Thermostat call for fan “G”

24 VAC thermostat input. A call for fan is recognized when the thermostat connects “G” to “R”. This input has an indicator LED in that will light when the control receives a call for fan. Refer to the Fan Mode section for the control operation.

B. Outputs

PSC Control

The control shall control a five speed indoor blower motor. Rating shall be 10 FLA, 30 LRA @ 120 VAC. Connections are made via 0.250 x 0.032” male quick connect terminals labeled “HEAT”, “COOL”, and “LOW”. “HEAT” is energized when the heat speed blower is to run. “COOL” is energized when the Cool speed blower is to run. “LOW” is energized during a call for fan is received or a call for dehumidification is received.

Oil Burner

Control

The control provides dedicated contacts to operate the T-T input of an oil primary control. Rating shall be class 2 – 24 VAC pilot duty @ 24 VAC (<200mA).

Power

The switched 120 VAC power from the LIMIT switch passes through the board between Pins 1 & 2 of connector P1.

EAC (electronic air cleaner)

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Contents DOWN FLOW & DIRECT VENT SEALED COMBUSTION MODEL: OMD-70 INSTALLATION AND SERVICE MANUALFOR YOUR SAFETY GAS-FIREDOR OIL-FIREDFURNACEI. 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 TABLE OF CONTENTS SECTIONBEGINNING PAGE a. Combustible material MODELS OMD/GMD b.Non-combustiblematerialIII. FURNACE SPECIFICATIONS MODELGMD-85 BLOWER DATA BURNER DATAIV. INSTALLATION A. ROOF JACK B. STANDARD CHIMNEYC.FURNACE LOCATION Figure 1A D. BASE INSTALLATIONCombustible Floor Base Model: 70-BASE Cottage Base Model: 01COT-BASE1. 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 F. CLOSET INSTALLATION E. ALCOVE 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 TERMINAL DEFINITIONS & FIELD WIRING 4. BLOWER CONTROLLER INFORMATION FOR PSC MOTORB. Outputs A. InputsC. Operating Modes DIAGNOSTIC FEATURES PSC TROUBLE SHOOTING5. 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 BURNER COMBUSTION PARAMETERS M. FLUE GAS COMBUSTION ANALYSISA. TROUBLESHOOTING V. DEALER MAINTENANCENote: Check diagnostic code through view port OMD/GMD TROUBLESHOOTING FLOWCHARTprior 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 C.HEAT EXCHANGER CLEANING INSTRUCTIONS B.CAD CELL CHECKOUT PROCEDURE: OMD ONLYD. CLEANING OR REPLACING FLUE PIPES E. EXTENDED SHUTDOWN A. WARNINGS AND CAUTIONS VI. USER INFORMATION SECTIONFigure C. INSPECTION AREAS B. COMPONENT LOCATIONSD.FILTER LOCATION AND CLEANING INSTALLATION / SERVICEE. CONTACT INFORMATION APPENDIX A. REPLACEMENT PARTS LIST