A.O. Smith 120 trough 500 manual General Questions and Answers, When should BTRs be delimed?

Page 45

BTR TANK TYPE HEATERS

SERVICE WORKBOOK

GENERAL QUESTIONS AND ANSWERS

Q.What changes caused series 106/107 and 108/109 to be implemented?

A.The 106 and 107 series units changed from the momentary push button to a slide

switch. The 108 and 109 series implemented a new main burner construction process. The damper boards with service switch and new style main burners will automatically be replacement parts for previous series heaters if parts are ordered.

Q.What is unique about the Canadian – BTRC – models vs. U.S. BTR models?

A.The Canadian models have different dimensions to meet Canadian code requirements.

Q:How much electrical power is required for a BTR water heater?

A:The BTR models draw approximately .7 Amps at 120VAC.

Q:The units require "leg kits" to meet National Sanitation Foundation standards. What are the part numbers for these kits?

A:The BTR model heaters need AOS kit numbers:

BTR 120-400 (except BTR 197&198 series 100) = Part # 6570-0 BTR 197&198 Series 100 = Part # 6570-5

BTR 500 = Part # 6570-7

Q:When should BTRs be delimed?

Many variables affect the liming up process including:

water temperature - The amount of lime accumulation during the same period of time will be nearly 2 times greater if water is stored at 140 degrees F than at 120 degrees F. A 180 degree setting will build up lime about seven times as fast as a 140 degree F setting. volume of water - The more gallons flowing through the BTR, the more rapid the accumulation.

hardness – The harder the water the faster lime build up occurs. 1 to 3.5 grains per gallon is "soft", 3.5 to 7 grains per gallon is "moderate", 7 to 10.5 grains per gallon is "hard" and 10.5 + grains per gallon is "very hard". (An aspirin is about 5 grains. One grain is equal to 17.1 parts per million.)

A:Deliming should be done when a slight rumbling or popping sound is detected when the main burners are on.

Q:What effect will lime build-up have on the BTR water heater?

A:One eighth inch of scale build-up may reduce efficiency as much as 22%; a 1/4 inch build-up,

as much as 38%.

A:Less efficient heat transfer means more bottom head expansion/contraction stress and

premature leakage.

A:Heavy build-up on the bottom head and bottom portion of the flue pipes leads to more heat transfer at the top of the flues. This can lead to stacking or erratic thermostat operation.

Q:Anode rods provide additional protection against corrosion. When should these be replaced?

A:When large gouges or pits appear in the anodes, replace them. It is recommended that these be inspected every 6 months.

A.O. Smith Water Products

44

Service Handbook

Irving, Texas ©2000

Training Department

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Page 44 Page 46
Contents Page BTR Handbook Table of Contents BTR Tank Type Heaters Service HandbookBTR Tank Type Heaters Service Handbook Clearances from Combustibles BTR Tank Type Heaters Service Handbook InstallationClearance to Combustibles Table ModelExterior Clearance Excess AIR AIR for Combustion Cubic Feet of AIR PER 1,000 BTUMAKE-UP AIR Direct CommunicationSquare Inch Per 4,000 Btuh Vertical Ducts Square Inch Per 2,000 Btuh Horizontal DuctsBackdraft Insufficient MAKE-UP AIRContaminated AIR AIR for CombustionFlammable Items Natural Gas Propane Gas GAS Pressure RequirementsBTR GAS Valve Venting Atmospheric Multiple HeatersChimney Draft Inducer Single Unit InstallationPower Vent Kits for Sidewall Venting Sequence of Operation BTR Sequence of Operation100 109 Series BTR Electrical SequenceBTR Electrical Sequence of Operation Troubleshooting BTR Water Heaters Step Test the TransformerThen Step High LIMIT, Left Terminal Test After Push in Reset 24 VAC is now present Reasons For Resetting Condition Cause SolutionStep Test High Limit Right Terminal Step Check the PC Board Step Inspect the DamperService Switch StepPC Board Motor Test Step Thermostat Test Test from Orange wire to Black neutral Step Damper Input TestTest the Damper Step Test Damper Output Effikal Damper Service SwitchAdapterNormal Operation Harness ChartStep a Test for 24VAC Between Black CommonNormal Operation Step BStep C Test for 24VAC Between Black and Yellow Step A1 Troubleshooting the Effikal Style DamperTest Between Black Common and Brown On the Damper BoardStep A3 Troubleshooting the Effikal Style DamperStep Wire Harness Test Step IID Module Test Step Pilot Spark Test BTR 120 400 GAS Valve Pilot Valve OHM TestPilot GAS Manifold Pressure TAP Blue White RED Pilot Valve Test BTR 500 onlyStep Main Burner Test Flame Rectification Step Flame RectificationPilot is lit Sparking has stopped Main GAS Valve Check Main GAS Valve Coil Check BTR 500 only Main GAS Valve Coil CheckHoneywell Ignition System 110 109 Series BTR Wiring Diagram Natural and Propane GASGeneral Service Chart When should BTRs be delimed? General Questions and AnswersSeries BTR Models 197BTR Models 197 Series Parts Description BTR Parts List for BTR Models 197 and 198 Series 100Series BTR Models 120 throughBTR Models 120 through Series 193873-1 193873-0 Component Part Information Name Specifications AOS Part NumbersBTR Service Checklist Proper Sequence of Operation Comments

120 trough 500 specifications

A.O. Smith, a renowned leader in water heating solutions, offers a wide range of products tailored to meet diverse needs. Among its most significant offerings is the A.O. Smith 120 through 500 series, which includes various models designed for both residential and commercial applications.

One of the standout features of the A.O. Smith 120 through 500 series is its efficiency. Many models are designed with advanced thermal insulation and heating technologies, which significantly minimize energy loss. This efficiency not only benefits the environment but also helps users save on energy bills, making these water heaters an economical choice for both homeowners and businesses.

The series includes both gas and electric water heaters, allowing users to select the option that best fits their energy preferences and availability. Gas models typically offer faster heating times and are ideal in areas where natural gas is readily accessible. Conversely, electric models come with a variety of voltage options, accommodating different electrical setups and preferences.

A notable technological advancement in the A.O. Smith 120 through 500 series is the incorporation of smart connectivity options. Some models are equipped with Wi-Fi capabilities, allowing users to monitor and control their water heater remotely via mobile apps. This feature provides real-time data, alerts, and updates, ensuring that users have complete control over their water heating needs.

Moreover, durability is a hallmark of the A.O. Smith brand. The tanks are often constructed from high-quality materials designed to resist corrosion. Many models also feature glass lining and protective coatings, which enhance the lifespan of the heater and minimize the risk of leaks.

Safety is another priority for A.O. Smith. The series is equipped with various safety features such as automatic shut-off mechanisms and temperature controls, ensuring that any potential issues are promptly addressed.

Overall, the A.O. Smith 120 through 500 series encapsulates innovation, efficiency, and reliability. With its versatile offerings and advanced features, it stands as an excellent choice for anyone in need of a dependable water heating solution. Whether for home use or in a commercial setting, these models deliver consistent performance and peace of mind.
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