5900 36TH AVE W BLDG A 2022 SOUNDVIEW EVERETT Plans 2025-01-07

SELECTION EXAMPLE - MODEL PTC (PROPELLER UNIT) MOD/NE Selection Procedure Selection Example (Propeller Unit) In order to properly select a unit heater it is necessary to have the following basic information. Selection Example Conditions(Propeller Unit) 1. Heating output capacity Select a unit heater to meet the following conditions: Model size output is to be matched against the heat loss to 1. Heating output capacity= 166,000 Btu/Hr per design be replaced. engineer 2. External static pressure =0.0 2. External static pressure (blower units only) 3. Internal statuic pressure = 0.0. No static producing The external static pressure (E.S.P.) is determined using the accessories are required. ASHRAE Guide for duct losses or provided by the design engineer. 4. Heat exchanger=409 Stainless Steel 5. Gas Type= Natural 3.Accessory internal static pressure(transitions,filters, 6. Gas Controls = Single Stage etc.) (blower units only) 7The critical accessories are those that add internal static Supply Voltage: 460V/60Hz/3Ph pressure (I.S.P.)to the unit. Once these items are determined, the total pressure drop can be determined With the information listed above, the basic model, using the (if applicable). information in this catalog and the Model Nomenclature shown 4. Heat exchanger material on page 19, can be selected as shown: The heat exchanger type is determined by the application. 1. Determine the Model and Input Rating (MBH): The standard heat exchanger material is aluminized steel. Using the Heating output capacity, the Furnace Input Rating A 409 stainless steel heat exchanger is recommended when is determined from Table 5.1. The closest model to 166,000 the combined entering/return air to the unit is below 40°F or Btu/Hr output has an Btu/Hr Input rating of 180,000 Btu/Hr so in high humidity applications. the Furnace Input Rating = 180. The corresponding model for 5.Type of fuel a 180 size, propeller, separated combustion unit heater is Either natural or propane gas determined by the design PTC.The model and size are a PTC180. engineer. 2. Determination of Heat Exchanger Material: 6. Gas controls From item#4 in the example, the Heat Exchanger required is 409 Stainless Steel. Thus, the Heat Exchanger Material = S Single stage, as determined by the design engineer. from the Model Nomenclature on page 19. 7. Main power supply voltage to unit 3. Determine the Ignition Type: The Ignition Type=S from the Model Nomenclature on page 19. 4. Determine Power Code Required: Referring to Table 5.2, it can be seen that the supply voltage from the example conditions is not available (460V). A transformer kit selected later in this example must be used. In this instance, from Table 5.2 select the 115V/60Hz/1Ph power code(PC) = 01 unit. 5. Determine the control type: From items#4 and#5 in the example conditions, the gas type is Natural Gas and controls are Single Stage. From Table 10.2, we are directed to use Control Code (CC) 11. 6. Determine the fan guard type: No specific type of fan guard was specified, so select Fan Guard = S from the Model Nomenclature on page 23. At this point we have a full model number of PTC180SS0111 SBAN 7. Determination of transformer: To operate a 115V/60Hz/1Ph unit on 460V/60Hz/3Ph supply power a unit step down transformer must be selected. By referring to Table 10.1 we see that a 460V to 115V step down transformer is required.As noted in the footnote for Table 10.1, the size can be determined to be 1.0kVA from Table 5.2. 6-170.7 13