Trane chiller tonnage by model number. Ascend™ Air-Cooled Chiller Model ACR With AdaptiSpeed™ Technology Quiet operation enabled by InvisiSound™ Technology March 2020 AC-PRC001C-EN Product Catalog

concept minimizes the chance of failure by reducing the number of critical parts—no gear boxes, couplings, extra shafts, or shaft seals. ... Trane chillers are frequently used in conjunction with combustion turbines to increase the power capacity, efficiency, and life of the turbine. ... The Series S™ CenTraVac™ chiller (model CVHS) is an ideal solution …

Trane chiller tonnage by model number. Trane’s air-to-water heat-pump chiller provides cooling or heating from one all-electric source, making it an effective—and more affordable—way to decarbonize. 3X more efficient. Ascend model ACX brings Trane’s proven, economical heat pump technology platform up to scale to provide heating or cooling for larger commercial

Jun 21, 2016 ... ... models operating with low Global Warming Potential (GWP) refrigerants ... Trane now offers CenTraVac heavy-tonnage chillers for applications ...

WarrantycoversCenTraVac™chillers(modelsCDHF,CDHH,CVHE,CVHF,CVHH,CVHL,CVHM, andCVHS)installedintheUnitedStatesandCanadathatshipfromthefactoryinLaCrosse, Wisconsin,September1,2004orlater.TThheeCCoommppaannyy''ssoobblliiggaattiioonnssaannddlliiaabbiilliittiieessuunnddeerrtthhiissFeb 23, 2021 ... Jump to Model ... That's where nominal tonnage and actual tonnage come in. The cooling capacity of a chiller, especially a packaged air-cooled ...

We create comfortable, energy efficient indoor environments for commercial and residential applications.Trane® CenTraVac™ Centrifugal Chillers. Since 1938, a Trane CenTraVac commercial chiller has led the industry as the most reliable, most efficient, lowest emission and quietest chiller in the world. Chiller performance can be verified on an AHRI-approved test stand. These CenTraVac chillers are among the Trane products within the EcoWise ...The Trane Comfort Coil unit is the industry’s first All-Aluminum coil. With over 10 years of performance, the Trane Comfort Coil has the reliability and efficiency you expect from Trane and the comfort your home deserves. Below are a few of the features and benefits that are included in the Comfort Coil design:To meet a wide range of applications in the 70–250 ton water-cooled market, Trane is proud to introduce the model RTWD helical-rotary liquid chiller. To meet a wide range of applications in the 70-200 ton condenserless market, Trane is offering the RTUD condenserless chiller. The introduction of this nex t-generation chiller is an exciting ...The CGAM air-cooled scroll chiller offers the perfect combination of flexibility, efficiency and low noise. Available in sizes ranging from 20 to 130 tons with a compact footprint, the CGAM is one of the quieter air-cooled chillers available today. Multiple levels of efficiency to choose from allow you to comply with your local code requirements. How to Read a Model Number Brand Name T = Trane Model Family P = P-Series Indoor Description KA0A = Wall Mounted CA0A = Ceiling Suspended LA0A =Ceiling Cassette VA0A =Air Handler EADA = Horizontal-ducted Capacity (BTU/H) 012 = 12,000 018 =18,000 024 =24,000 030 =30,000 036 = 36,000 042 =42,000 TP KA0A 0121KA70 A Chassis …Trane's air-cooled chiller lineup gives you the flexibility to choose from a wide range of capacities and features. From outstanding eficiency to amazing acoustics, to occupant comfort and well-being. You can have it all... in varying degrees. Get the results you need. SustainabilityModel Number: RTHD · Year: 2011 · 300 Tons Nominal Cooling · 460V/3Ph/60Hz · Refrigerant: R-134a · Rotary Screw Compressor · Shell & Tube Condenser Heat Exchanger ...20 To 130 Tons Cgam Trane Air Cooled Chiller. ₹ 65,000/ Unit Get Latest Price. Tonnage: 20 to 130 tons. Brand: Trane. Model Name/Number: CGAM. Refrigerant Used: R410A. Temperature Range: -20 to 125 Deg F. Frequency Hz: 50 and 60 Hz.Trane AC model numbers have nine identifying letters and numbers, with each place in the line signifying a specific piece of information. For example, the first spot in the model number identifies the AC unit’s brand, and the last spot is t...

IntelliPak 2 offers unit design flexibility that adapts easily to diverse applications and settings. It provides superior static pressure in buildings up to seven stories. Available in sizes ranging from 90 – 150 tons. Ideal for office buildings, healthcare, education, data centers, retail, and entertainment facilities.©2022 Trane RLC-PRC020K-EN Introduction To meet a wide range of applications in the me dium-tonnage, water-cooled market, Trane is proud to recommend the model RTHD helical-rotary liquid chiller.This chiller provides application versatility, ease of installation, control precision, reliability, energy efficiency, and operationalLiquid Chillers 70-250 Tons Model RTWD Water-Cooled 70-200 Tons Model RTUD Condenserless Made in USA ... Trane is proud to introduce the model RTWD helical-rotary liquid chiller. To meet a wide range of applications in the 70-200 ton condenserless market, Trane is offering the RTUD condenserless chiller. The ... Model Number Descriptions ...Mar 18, 2019 · Look for the last two numbers of the first numbers after a cluster of letters at the beginning of the model number. It will be a number divisible by 6 or 12, and represents the nominal BTU of the system in thousands. A ton of air conditioning equals 12,000 BTU, and 36 divided by 12 equals 3, so the data plate below indicates the system is 3 tons.

Directory ofCertified Product Performance. Search By: AHRI Reference #. Model Number. Product Type. Additional Resources. User Guide and FAQs.

Aug 2, 2021 · After the last two digits of the first digits, Trane model numbers often start with a series of letters. To give you an idea of the scale of things, consider this: 18 = 1.5 tonnes, 24 = 2 tonnes, 30 = 2.5 tonnes, 36 = 3 tonnes, 42 = 3.5 tonnes, 48 = 4 tonnes, 60 = 5 tonnes.

Our locations carry Trane OEM parts built to the original equipment specifications and are proven to support Trane equipment. Shop at Trane Supply today! ... Trane branded R-22 and R-410A, 6.2 ton - 30 ton, light commercial & commercial scroll compressors are built to the same tolerances and standards of the compressors in the original equipment. ...Trane Performance Climate Changer air handlers are designed to optimize your HVAC system with high energy efficiency, indoor air quality, and low maintenance. Learn more about the features and benefits of this versatile and reliable air handler model in …The Series L™ CenTraVac™ chiller (model CVHL) is a direct result of the Trane commitment to provide the right technology for the right application at the right time. Because industrial processes and data center applications have unique cooling requirements, theACX. Enabled by Symbio® 800 wireless connectivity. Capacity Range: 140 to 230 tons cooling; 1500 to 2500 MBh heating. Refrigerant: R-454B. Heating fluid temperatures up …

Trane Heating & Air Conditioning©2022 Trane RLC-PRC040G-EN Introduction. To meet a wide range of applications in the 65-240 ton water-cooled market, Trane is proud to offer the model RTWD helical-rotary liquid chiller. This next-gener ation chiller provides application versatility, ease Water-Cooled Helical Rotary Chiller. At a glance. Capacity Range: 80 to 450 tons, 60 Hz; 60 to 450 tons, 50 Hz. Refrigerant: R-134a or R-513A. Best Full-load Efficiency: 0.6200 kW/ton (at AHRI conditions) Best Part-load Efficiency: 0.4800 kW/ton. Compressor Type: Helical Rotary. Medium Pressure. CVHEwAFD-Hinges-535x339.jpg.These CenTraVac chillers are among the Trane products within the EcoWise™ product portfolio and can operate with either R123 or next-generation refrigerants R514A or R1233zd, both featuring ultra-low global warming potential (GWP) of less than 2. Most Efficient - Selectable commercial chiller with full load efficiencies down to 0.45 kW/ton at …Tons Unit Model Number Standard Evaporator Fan Motor Oversized Evaporator Fan Motor No. Volts Phase Hp Amps No. Volts Phase Hp Amps FLA FLA 7.5 E/GCC090A 1 203-230 3 2 7.2 1 203-230 3 3 12 8.5 E/GCC102A 1 203-230 3 2 7.2 1 203-230 3 5 14.6 10 E/GCC120A 1 203-230 3 3 12 1 203-230 3 5 14.6 12.5 E/GCC150A 1 203-230 3 3 12 1 203-230 3 5 14.6WarrantycoversCenTraVac™chillers(modelsCDHF,CDHH,CVHE,CVHF,CVHH,CVHL,CVHM, andCVHS)installedintheUnitedStatesandCanadathatshipfromthefactoryinLaCrosse, …Let Cold Shot Chillers® help you properly estimate and then manufacturer the perfect chiller for your specific ... Properly sizing a chiller for your application can depend on a large number of variables. ... Ton Capacity = 239,904 BTU/hr. ÷ 12,000 = 19.992 Tons; Oversize the chiller = 19.992 x 1.2 = 23.9904; A 23.9904 or 25-Ton chiller is ...You can find the Trane tonnage and SEER in the 5 th, 7 th and 8 th characters of the Trane model number. The 5 th character represents SEER in a single number; the 7 th and 8 th characters, also numbers, show the tonnage code. The Trane model number nomenclature for central air conditioners and heat pumps is explained below in this Trane model ...View & download of more than 8942 Trane PDF user manuals, service manuals, operating guides. Air Conditioner, Heat Pump user manuals, operating guides & specifications. Sign In Upload. Manuals; ... Show all Trane Chiller manuals . Chiller Control System. Models . Document Type . RLC-SVU02F-E4 . Owner's Manual ... Model 012 GEH . Operation …Let Trane Select Assist help you to determine the Trane equipment that best suits the HVAC needs of your project. Learn more BIM-Revit. ... Ascend(TM) Air-Cooled Chiller Model ACRB 150/165T 4V 2 Pass Transformer; ACRB - 180/200T 5V 2 pass no options ; ACRB - 180/200T 5V 2 pass Transformer; ACRB - 165T 5V 2 Pass Free Cooling ... Test …Series R™ Helical Rotary Liquid Chillers Model RTHD 175~450 Tons (60 Hz) 125~450 Tons (50 Hz) Built for Industrial and Commercial Applications. 2 RLC-PRC031B-EN Introduction To meet a wide range of applications in the medium-tonnage, water-cooled market,Trane is proud to recommend the model RTHD helical-rotary liquid chiller.This …To meet a wide range of applications in the me dium-tonnage, water-cooled market, Trane is proud to recommend the model RTHD helical-rotary liquid chiller.This chiller …This Used Trane 120 Ton Air Cooled Chiller (Qty 2) has been inspected and is located in our facility in Bridgeport, Tx. We Buy and We Sell New and Used Chillers, Cooling Towers and Equipment. ... Model Number: CGAM120; Year: 2015; 120 Tons Nominal Cooling; 208-230V/3Ph/60Hz; Refrigerant: R-410a; Microchannel Condenser Coils; Scroll …Air Conditioner trane IntelliPak Programming Manual. With symbio 800, 20 to 75 ton with the tracer td7 display (88 pages) Air Conditioner Trane Voyager III Installation Manual. Variable frequency drive conversion tr1 to tr200 (24 pages) Air Conditioner Trane IntelliPak Signature Series Programming Manual.120–4000+ Tons (450–14000+ kW), 60 and 50 Hz March 2020CTV-PRC007R-EN Product Catalog ©2020 CTV-PRC007R-ENTrane Introduction World’sMostEfficientLowestEmissionsChillerAug 10, 2016 · Trane Tonnage from Model Number. TTP018 = 1-1/2ton; TTP024 = 2 ton; TTP030 = 2 1/2 ton; TTP036 = 3 ton; TTP042 = 3 1/2 ton; TTP048 = 4 ton; Example of Trane Model Identification. The Trane model number is #TWE030C140B0, let’s try to decode this model number: TW = split component heat pump compatable Trane® Air-Cooled Scroll Chillers Efficient, flexible and quiet—the perfect balance of sound and efficiency for your small jobs Model CGAM – 20-130 tons ... 20 to 35 ton 47.2 1200 31.5 800 23.6 600 39.4 1000 40 to 70 ton 47.2 1200 31.5 800 39.4 1000 39.4 1000 80 to 130 ton 47.2 1200 39.4 1000 39.4 1000 39.4 1000 ... Number of fans and panel doors shown …Jul 22, 2022 · Trane age of unit – here is how to read a Trane serial number: For units made from 2002 to 2009 , the first number represents the year: 2 is 2002, 3 is 2003, etc. The next two numbers are the week of the year, so 01 would be the first week in January, and 52 would be the last week in December. Chiller Trane RTHC Installation Operation & Maintenance. 175-450 ton units (60 hz); 125-450 ton units (50 hz) (168 pages) Chiller Trane RTHA Installation, Operation And Maintenance Manual. Solid state starter conversion (48 pages) Chiller Trane RTCA 108-216 Installation And Operation Manual.

To meet a wide range of applications in the me dium-tonnage, water-cooled market, Trane is proud to recommend the model RTHD helical-rotary liquid chiller.This chiller provides application versatility, ease of installation, control precision, reliability, energy efficiency, and operational costeffectiveness.The RTHD chiller is designed to delive... Water-Cooled Helical Rotary Chiller. At a glance. Capacity Range: 80 to 450 tons, 60 Hz; 60 to 450 tons, 50 Hz. Refrigerant: R-134a or R-513A. Best Full-load Efficiency: 0.6200 kW/ton (at AHRI conditions) Best Part-load Efficiency: 0.4800 kW/ton. Compressor Type: Helical Rotary. Medium Pressure. CVHEwAFD-Hinges-535x339.jpg.Parts & Supplies. At Trane Supply, we have the parts and the knowledge to support all of your HVAC needs, no matter what system you are working on. You can rely on us to deliver a solution to meet your customers’ needs, and to help you be more productive, profitable, and knowledgeable. Along with our technical expertise, we focus on providing ...The tonnage of an AC unit can typically be determined from the model number by looking for a number that is divisible by 12. For example, if the model number is ABC12345, and the number 36 appears in the middle of the model number (e.g., ABC36 12345), then the AC unit is likely a 3-ton unit, since 36 is divisible by 12.Directory ofCertified Product Performance. Search By: AHRI Reference #. Model Number. Product Type. Additional Resources. User Guide and FAQs.Model Number Distinguisher Major Design Change Efficiency C - Standard S - Hi Efficiency Refrigerant Control 3 - TXV - Non-Bleed Coil Circuitry ... Model 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 4TXCA002DS3HCB 225 340 430 510 585 650 715 775 ... Trane - by Trane Technologies (NYSE: TT), a global climate innovator - creates comfortable, energy …Trane Commercial Parts. Founded in 1885 as a family plumbing business, Trane, Inc. is a leading manufacturer of HVAC systems. It manufacturers commercial units like: Water-Cooled, Air-Cooled & Modular Chillers. P Series, NV Series & N-Gen Ductless Systems. Rooftop, Split & Self-Contained Packaged Units.

IntelliPak 2 offers unit design flexibility that adapts easily to diverse applications and settings. It provides superior static pressure in buildings up to seven stories. Available in sizes ranging from 90 – 150 tons. Ideal for office buildings, healthcare, education, data centers, retail, and entertainment facilities. ©2023 Trane CG-PRC017T-EN Introduction Design and manufacturing excellence makes Trane a leader in the air-cooled chiller market place. This tradition of using excellence to meet market demands is illustrated with the Trane 20 to 130 ton air-cooled scroll chiller. This next-generation chiller is an exciting step forward in energy-efficiency ... Chiller Trane RTAA-130 Installation, Operation And Maintenance Manual. Air-cooled series r rotary liquid chillers (140 pages) Chiller Trane RTHD series Installation, Operation And Maintanance. Series r helical rotery liquid chillers with heat recovery option. 175-450 ton units (60 hz), 125-410 ton units (50 hz) (150 pages) Chiller Trane City ...Trane®Air-Fi®WirelessCommunicationInterface X Trane®CommunicationInterface X Note:Formoreinformation,referencetheControlschapter. (a) ... (YHC)models. Typical5tonTHC060E OAConditions RAconditions 2000cfmTotalSupplyAirflow Partloaddayandraining 75ºFdb 800cfmOutsideAir(40%) ...The Series L™ CenTraVac™ chiller (model CVHL) is a direct result of the Trane commitment to provide the right technology for the right application at the right time. Because industrial processes and data center applications have unique cooling requirements, theModel Number Digits 1, 2 - Unit Model RT = "Rotary Chiller" Digit 3 - Unit Type A = Air Cooled Digit 4 - Project Sequence C = Sequence C Digits 5, 6 e 7 - Nominal Capacity 140 = 140 Nominal Tons 155 = 155 Nominal Tons 170 = 170 Nominal Tons 185 = 185 Nominal Tons 200 = 200 Nominal Tons 225 = 225 Nominal Tons 250 = 250 Nominal Tons 275 = 275 ... Trane’s air-to-water heat-pump chiller provides cooling or heating from one all-electric source, making it an effective—and more affordable—way to decarbonize. 3X more efficient. Ascend model ACX brings Trane’s proven, economical heat pump technology platform up to scale to provide heating or cooling for larger commercial Trane is a manufacturer of commercial and residential heating, ventilation, and air conditioning (HVAC) systems, along with building management systems and controls. …As electricity costs continue to rise, Trane positions itself to be "simply the best" in 13 SEER packaged rooftop products. By taking guidance from HVAC professionals across the country, we designed the equipment to delight installers, service technicians and building owners based on our tradition of quality and reliability.Trane BYC100 model number decode. I'm pretty sure its an 8.5T, Can make out 250mbh input. know the voltage from the panel..duh! Anyone recall what tonnage this is in Trane speak? Its OLD and I'm a Carrier type of guy. Thanks in advance.Enjoy the convenience of decoding multiple units simultaneously with our batch lookup tool. We are currently working on a model number decoder where we can bring you vital unit specifications based on model number. This information portal is put together by a few enthusiasts with the goal to remove friction for HVAC technicians and professionals. trane chiller model & serial number assistance - hvac-talk Web Mar 14, 2018 Model - CVHE-028F-AG-2KB2533CE1C13CEZ00000000061C00 Serial # L85E28540 Chiller Two: Model - CVHE-028F-AG … From hvac-talk.comModel Number Digits 1, 2 - Unit Model RT = "Rotary Chiller" Digit 3 - Unit Type A = Air Cooled Digit 4 - Project Sequence C = Sequence C Digits 5, 6 e 7 - Nominal Capacity 140 = 140 Nominal Tons 155 = 155 Nominal Tons 170 = 170 Nominal Tons 185 = 185 Nominal Tons 200 = 200 Nominal Tons 225 = 225 Nominal Tons 250 = 250 Nominal Tons 275 = 275 ... Model: The Unit Model Number: Note- It is very important to remember that the AAF and HermanNelson model numbers differ from all the other brand names listed in the index in that the model number is located in the middle of the alpha/numeric model number string. (Example: SPAGAAPFCWG53211000. The bold letters indicate the model number.Goodman air conditioning unit tonnage can be determined by the unit’s model number. This number is located on a plate attached to the back of the unit, near the power supply and coolant lines.To meet a wide range of applications in the me dium-tonnage, water-cooled market, Trane is proud to recommend the model RTHD helical-rotary liquid chiller.This chiller provides application versatility, ease of installation, control precision, reliability, energy efficiency, and operational costeffectiveness.The RTHD chiller is designed to delive... • Compressor model number. • Compressor serial number. • Compressor electrical characteristics • Utilization range. • Recommended refrigerant See Model Number Descriptions chapter for compressor model and serial number descriptions.

SSeerriiaall NNuummbbeerr..The unit serial number provides the specific chiller identity. Always provide this serial number when calling for service or during parts identification. SSeerrvviiccee MMooddeell NNuummbbeerr..The service model represents the unit as built for service purposes. It identifies the selections of variable unit features ...

I forget what the trane is, but probably the same McQuay chillers m# PEH079 S# 5YC0100700 style 0547362010 m# PEH076 S# 5ZA81012-01 style 9566323018 trane screw centravac m# RTHA130FCMONDUC3LF2LFNN00GUQ S# U90K03031 device# 3036RT130 appreciate it building engineer would like something more than a shoot from the hip nominal tonnage.

IPLV to 0.31 (19XRV) Chlorine-free HFC-134a refrigerant. Semi-hermetic compressor motor. Low energy consumption during part load and full load operation. Aerodynamically contoured impeller. Multilingual display. Compatible with Carrier Comfort Network® (CCN) communication link. Two stage compressor economized (19XR two-stage units)The prices listed here reflect the national average costs of installing of a new HVAC system or unit. The prices are estimates, for convenience only and subject to change. Trane makes no representation as to the accuracy of the pricing of any product displayed, and your dealer may quote you a different price that is not shown here. AC Tonnage = 2.5 Tons. You can get AC tonnage by the general estimation that the digits “30” indicate 30,000 BTU of cooling capacity in your air conditioner. As 12,000 BTU is the cooling capacity of a one-ton unit, dividing 30,000 by 12,000 will directly give you 2.5 as result. View online or download Trane YSC120 Installation Operation & Maintenance. ... Model Number Description. 2. ... Air Conditioner Heat Pump Chiller Air Handlers Thermostat.Trane® Air-Cooled Scroll Chillers Efficient, flexible and quiet—the perfect balance of sound and efficiency for your small jobs Model CGAM – 20-130 tons ... 20 to 35 ton 47.2 1200 31.5 800 23.6 600 39.4 1000 40 to 70 ton 47.2 1200 31.5 800 39.4 1000 39.4 1000 80 to 130 ton 47.2 1200 39.4 1000 39.4 1000 39.4 1000 ... Number of fans and panel doors shown …Originally Posted by nolesman98. Trane XE1100 old 1996 condenser unit. model#: TTN 024 D100A1. serial#: L3244WDBF. I REALL JUST NEED TO KNOW TONNAGE. pLEASE HELP. 024 = 24,000 btuh or 2 ton. Instead of learning the tricks of the trade, learn the trade.Feb 23, 2021 ... Jump to Model ... That's where nominal tonnage and actual tonnage come in. The cooling capacity of a chiller, especially a packaged air-cooled ...Find information about Trane serial numbers at Trane.com. Click the Go to Trane Residential link under the Residential heading on the home page. Next, click the Warranty & Registration link under the Owner’s Support heading.

kelley blue book 2014 camrypacific border crossing cameraszaxby's club sandwich discontinuedclip studio animation tutorial Trane chiller tonnage by model number husqvarna z254f deck belt diagram [email protected] & Mobile Support 1-888-750-6748 Domestic Sales 1-800-221-6130 International Sales 1-800-241-7923 Packages 1-800-800-8016 Representatives 1-800-323-3994 Assistance 1-404-209-3749. 120–4000+ Tons (450–14000+ kW), 60 and 50 Hz March 2020CTV-PRC007R-EN Product Catalog ©2020 CTV-PRC007R-ENTrane Introduction World’sMostEfficientLowestEmissionsChiller . philips cl5 remote codes BIM and Selection Tools. Access the technical files you need to confidently design HVAC system projects with ease. Quickly download BIM-Revit or CAD drawings and detailed documents based on project needs. And coming soon, be on the look out for a new, user-friendly filtering tool for drawings and technical documents. da-topss-page.jpg.Trane CenTraVac® chillers feature a time-tested and proven low-pressure design utilizing environmentally friendly refrigerants R-514A and R-1233zd. They provide the safety of low pressure with continued product enhancements in a leak-tight design. Available in a wide range of cooling capacities, CenTraVac chillers provide from 120 to 2,000 ... la bestia gruperalowes richmond ca Whether you need to make a warranty claim or find replacement parts, there are plenty of reasons why you may need to find the model number for your GE motor. Here are several helpful tips you can use to find your motor’s model number. unrestricted land for sale owner financing virginiachicago accuweather monthly New Customers Can Take an Extra 30% off. There are a wide variety of options. ©2021 Trane RLC-PRC029K-EN Introduction To meet a wide range of applications in the 75-240 ton water-cooled market, Trane is proud to offer the model RTWD helical-rotary liquid chiller. To me et a wide range of applic ations in the 70-200 ton condenserless market, Trane is offering the RTUD condenserless chiller. This next-generation Capacity Range: 20 to 130 tons (50 and 60 Hz) Refrigerant: R-410A Energy Efficiency Rating (EER): IPLV: 13.7-16.6 (high-efficiency); 14.5-16.9 (extra-high-efficiency) Sintesis® Air-Cooled Chillers At a Glance: Capacity Range: 115 to 520 tons Refrigerant: R-134a or R-513A Compressor Design: Helical rotary screwThe first digit is the year of production (with "3" representing 1973). The next digit reveals the calendar quarter, ranging from "01" for the 1st quarter to "04" for the 4th quarter. The final four digits are a unique sequence number. So, a serial number like 312345 means the unit was made in the first quarter of 1973.