A.O. Smith TWI 35-130, TWI 45-190 service manual Maintenance, Introduction Prepare maintenance

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10 Maintenance

10.1Introduction

10.2Prepare maintenance

Service shall be carried out at least once a year both on the gas side and on the water side. The frequency of the maintenance depends, among other things, on the water quality, the average number of operating hours per day and the set water temperature.

Remark

Regular maintenance lengthens the life of the device. For determining the correct maintenance frequency, it is advised to have the service and maintenance engineer check the gas side and the water side of the device three months after installation. The maintenance frequency can be determined on the basis of this check.

Proceed as follows for testing the proper functioning of all components:

1.Maximally turn the thermostat counterclockwise.

2.Wait until the fan stops.

3.Turn the thermostat to its original position. Then draw off water to create a heat demand.

4.Check if the heating cycle runs correctly (7.3 “Heating cycle of the device”).

5.Check the CO2-value and adjust this if necessary (3.11 “Check and adjust the CO2-value”).

6.Check all parts of the flue gas discharge system for proper fastening.

7.Check the pressure difference of the pressure switch (see the table). Clean the heat exchanger and burner if the pressure difference is too low (10.4.2 “Clean the burner” AND 10.4.3 “Clean heat exchanger”).

Pressure difference of air pressure switch

Device

Measured pressure difference over air pressure switch

TWI 35-130

≥ 730 Pa

TWI 45-190

≥ 400 Pa

8.Test the functioning of the expansion valve of the protected cold supply setup. The water has to flow out in a forceful jet.

9.Test the functioning of the T&P valve (if applicable). The water has to flow out in a forceful jet.

10.Check the discharge pipes of the expansion valve and remove any present scale deposits.

11.Drain the device (see Drain).

Instruction manual TWI 35-130 G/TWI 45-190 G

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Contents 35-130 45-190 Your installer Page Page Copyright 2007 A.O. Smith Water Products Company Page Operation of the device InstallationErrors MaintenanceWarranty certificate Table of contentWhat to do when you smell gas Regulations IntroductionAbout the device Target groups IntroductionChapter Target groups Description InstallationThis chapter contains the terms of warranty Warranty certificateIntroduction This chapter will cover in the given order Operation of the deviceOperation of the device Heating cycleSecurity of the device Introduction 4 Fan Security of the water temperatureAir pressure switch Gas controlUnvented installation Vented installation3 T&P valve Packaging InstallationInstallation Working area Dimension Description TWI Dimensions of the deviceDescription Unit TWI Dimension Description TWIVented Condensation drainage Cold water sideHot water side Circulation pipingRequirements for flue gas discharge material Air supply and flue gas discharge IntroductionDevice types Practical example of concentric flue gas discharge Example Device types DescriptionConcentric connections Device Diameter Maximum length Maximum num Ber of 90 bendsSubject Description SpecificationsPractical example of parallel flue gas discharge Example Parallel connectionsDevice Diameter Maximum running length BendDevice with parallel flue gas discharge material Preparation Electrical connectionConnector block Isolating transformer Check and adjust the CO2-value Connect the mains voltageGas control Checking procedureAdjust the CO2-value Conversion to another gas category Conversion to another gas category Unvented FillFill vented installations Fill the device Fill unvented installationsDrain Installations Drain unventedDrain vented Start up Opening the gas valve 3.5 Connections diagramStart up Electrically isolate Shut downIntroduction You can For a short timeShut down Errors Introduction Distinction is made between General errorsErrors visible on the control Symptom Cause Solution Remark Gas smell Water leakageExplosive ignition Hot water Symptom Cause Solution Remark Insufficient or noLight pulses Cause Solution Remark Troubleshooting table for errors visible on the controlSee 12.2 Electrical circuit diagram Light pulses Cause Solution Remark SL3TWI Introduction Prepare maintenance MaintenanceMaintenance 11.3 Conditions Warranty certificate11.1 Warranty general 11.2 Warranty tankSmith Warranty certificate11.6 Claims 11.7 ObligationsAnnex Annex Electrical circuit diagramWiring Annex Connect IndexIndex User WarrantyPage 0308 489 R1.0

TWI 35-130, TWI 45-190 specifications

A.O. Smith TWI 35-130 and TWI 45-190 are high-efficiency water heaters designed to meet the diverse needs of residential and commercial applications. These units are part of A.O. Smith’s extensive product line, known for reliability, durability, and energy efficiency.

The TWI 35-130 model is a 35-gallon tank water heater, offering a first-hour delivery of 130 gallons. This capacity makes it suitable for households with moderate hot water demands. It features a compact design, allowing for easy installation in tighter spaces, which is ideal for urban settings. The unit operates on natural gas, promoting energy efficiency while reducing operational costs.

One of its main attributes is the advanced insulation technology that minimizes heat loss, thus enhancing overall energy efficiency. The TWI 35-130 is equipped with a state-of-the-art burner system that optimizes combustion for higher efficiency, translating to lower energy bills. Furthermore, it utilizes a dip tube that helps in delivering hot water promptly, ensuring that the demand for hot water is met swiftly.

On the other hand, the TWI 45-190 model caters to larger households or commercial settings with a 45-gallon capacity and a first-hour delivery of 190 gallons. This model also uses natural gas, but with a higher BTU rating, allowing for faster recovery rates, which is crucial during peak usage times.

Both models are designed with user-friendliness in mind, featuring intuitive controls that facilitate easy temperature adjustments and monitoring. Additionally, they incorporate safety features such as a temperature and pressure relief valve to prevent overheating and excessive pressure build-up, ensuring peace of mind for users.

Their innovative design also emphasizes longevity, with high-grade materials and protective coatings that resist corrosion and extend the lifespan of the tank. The TWI series stands out in the market not only for its performance and efficiency but also for its commitment to sustainability.

In summary, A.O. Smith's TWI 35-130 and TWI 45-190 water heaters bring together cutting-edge technology, efficiency, and reliability, making them excellent choices for both residential and commercial applications. With features designed to promote energy savings and user convenience, these models are poised to meet the hot water demands of modern life while adhering to high standards of safety and durability.
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