Carrier 58MVP Installation, Start-up, And Operating Instructions Manual

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Carrier 58MVP Installation, Start-up, And Operating Instructions Manual Manual pdf 22 page image

control. (See Fig. 27 and 28.) When a dehumidify demandexists, relay is de-energized, and normally closed contactssupply 24v to the furnace DEHUM terminal. As a result, thefurnace control reduces the blower airflow by 15 percent to340 CFM per ton during continuous fan or cooling operation.On newer style variable speed furnace controls a field suppliedrelay IS NOT required. The DEHUM output on the thermi-distat control or the humidistat output is connected directly tothe DEHUM terminal on the furnace control. In addition, theDE jumper located next to the DEHUM terminal must beremoved to enable the DEHUM input. (See Fig. 27 and 29.)When a dehumidify demand exists, the furnace control re-duces the blower airflow by 21 percent to 315 CFM per tonduring continuous fan or cooling operation.DIRECT VENTINGThe 58MVP Furnaces require a dedicated (one 58MVP furnaceonly) direct-vent system. In a direct-vent system, all air forcombustion is taken directly from outside atmosphere, and all flueproducts are discharged to outside atmosphere.Step 1—Removal of Existing Furnaces fromCommon Vent SystemsIf furnace being replaced was connected to a common vent systemwith other appliances, the following steps shall be followed witheach appliance connected to the venting system placed in opera-tion, while any other appliances connected to the venting systemare not in operation:1. Seal any unused openings in the venting system.2. Inspect the venting system for proper size and horizontal pitchas required in the National Fuel Gas Code, NFPA 54-1996/ANSI Z223.1-1996 or the CAN/CGA B149 InstallationCodes and these instructions. Determine that there is noblockage or restriction, leakage, corrosion, and other deficien-cies which could cause an unsafe condition.3. If practical, close all building doors and windows and all doorsbetween the space in which the appliance(s) connected to theventing system are located and other spaces of the building.Turn on clothes dryers and any appliance not connected to theventing system. Turn on any exhaust fans, such as range hoodsand bathroom exhausts, so they shall operate at maximumspeed. Do not operate a summer exhaust fan. Close fireplacedampers.4. Follow the lighting instructions. Place the appliance beinginspected in operation. Adjust thermostat so appliance shalloperate continuously.5. Test for draft hood equipped appliance spillage at the drafthood relief opening after 5 minutes of main burner operation.Use the flame of a match or candle.6. After it has been determined that each appliance connected tothe venting system properly vents when tested as outlinedabove, return doors, windows, exhaust fans, fireplace damp-ers, and any other gas-burning appliance to their previousconditions of use.7. If improper venting is observed during any of above tests, theventing system must be corrected.Vent system or vent connectors may need to be resized. For anyother appliances when resizing vent systems or vent connectors,system or connector must be sized to approach minimum size asdetermined using appropriate table found in the NFGC or NSC-NGPIC.Step 2—Combustion-Air and Vent PipingGENERALCombustion-air and vent pipe fittings must conform to AmericanNational Standards Institute (ANSI) standards and AmericanSociety for Testing and Materials (ASTM) standards D1785(schedule-40 PVC), D2665 (PVC-DWV), D2241 (SDR-21 andSDR-26 PVC), D2661 (ABS-DWV), F628 (schedule-40 ABS), orF891 (PVC-DWV cellular core). Pipe cement and primer mustconform to ASTM standards D2564 (PVC) or D2235 (ABS). SeeTable 6 for maximum pipe lengths and Fig. 34, 35, 36, 37, and 38for exterior piping arrangements.In Canada, construct all combustion-air and vent pipes for this unitof CSA or ULC certified schedule-40 PVC, PVC-DWV orABS-DWV pipe and pipe cement. SDR pipe is NOT approved inCanada.NOTE: Furnace combustion-air and vent pipe connections aresized for 2-in. pipe. Any pipe size change should be made outsidefurnace casing in vertical pipe. (See Fig. 30.) This allows properdrainage of vent condensate.Combustion-air and vent pipes must terminate together in sameatmosphere pressure zone, either through roof or sidewall (rooftermination preferred), using accessory termination kit. See Table5 for required clearances.Furnace combustion-air and vent pipe connections must be at-tached as shown in Fig. 31. Combustion-air intake plug fitting andinducer housing alternate vent cap may need to be relocated insome applications.→ Fig. 28—Without DE ConnectionA9829424 VAC HOTDEHUMIDIFY24 VAC COMMR RDHUMDEHUMCComTHERMIDISTATVARIABLE-SPEEDCONDENSINGFURNACE→ Fig. 29—With DE ConnectionA9829524 VAC HOTDEHUMIDIFY24 VAC COMMR RComDHUM DEHUMCDENOTE 1THERMIDISTATVARIABLE-SPEEDCONDENSINGFURNACENOTE 1 - Remove DE ConnectionTo Enable DEHUM Input22→→→