A.O. Smith TWI 45-190 Operation of the device, Heating cycle, Security of the device Introduction

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2

Operation of the device

 

 

In this device the cold water is supplied through the cold water inlet (16) at the

 

 

bottom of the tank. The tap water heated by the combustion chamber (15) and

 

 

heat exchanger (13) leaves the tank at the hot water outlet (12). If the device

 

 

is maximally filled with water, there is a constant water piping pressure. When

 

 

tapping hot water from the device, cold water is immediately added again.

 

 

The device has been provided with an e premix burner (4) with 1:1 gas/air ratio

 

 

control. The fan (10) sucks in the air that is required for the combustion. The

 

 

gas is supplied through the gas control (7) and the venturi on the suction side of

 

 

the fan. The 1:1 gas/air coupling always ensures an optimum gas/air ratio.

 

 

Because of the special construction of the heat exchanger (13), the flue gasses

 

 

are first led up through the combustion chamber and then down through the

 

 

heat exchanger along the water. This gradually cools down the flue gasses. As

 

 

the cooled down flue gasses are finally led along the cold water at the bottom

 

 

of the tank as well, the flue gasses start condensating. Condensation causes

 

 

release of energy (heat) that is also transferred to the water, which improves the

 

 

output. The condensate that is formed with this heating is discharged through

 

 

the siphon (20). The insulating layer (2) prevents loss of heat.

2.3

Heating cycle of

The temperature sensor (1) measures the water temperature. As soon as

 

the device

the measured temperature is below the set water temperature, the electronic

 

 

control observes a ‘heat demand’. The gas control (7) opens after about half

 

 

a minute and the gas mixes with the air. The hot surface igniter (9) ignites

this mixture and the water is heated. As soon as the measured temperature is above the set water temperature, the heat demand ends and the electronic control stops the heating cycle.

2.4Security of the device

2.4.1Introduction

The electronic control monitors the water temperature and ensures safe combustion.

This is done by:

the Security of the water temperature;

the Gas control;

the Fan;

the Air pressure switch;

the Ionisation detection.

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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 Maintenance InstallationErrors Operation of the deviceTable of content Warranty certificateAbout the device What to do when you smell gas RegulationsIntroduction Introduction Target groupsInstallation Chapter Target groups DescriptionWarranty certificate This chapter contains the terms of warrantyOperation of the device Introduction This chapter will cover in the given orderSecurity of the device Introduction Operation of the deviceHeating cycle Gas control Security of the water temperatureAir pressure switch 4 Fan3 T&P valve Unvented installationVented installation Installation PackagingInstallation Working area Dimensions of the device Dimension Description TWIDimension Description TWI Description Unit TWIVented Circulation piping Cold water sideHot water side Condensation drainageAir supply and flue gas discharge Introduction Requirements for flue gas discharge materialDevice types Device Diameter Maximum length Maximum num Ber of 90 bends Device types DescriptionConcentric connections Practical example of concentric flue gas discharge ExampleSpecifications Subject DescriptionBend Parallel connectionsDevice Diameter Maximum running length Practical example of parallel flue gas discharge ExampleDevice with parallel flue gas discharge material Electrical connection PreparationConnector block Check and adjust the CO2-value Connect the mains voltage Isolating transformerChecking procedure Gas controlAdjust the CO2-value Conversion to another gas category Conversion to another gas category Fill UnventedFill the device Fill unvented installations Fill vented installationsDrain Drain vented InstallationsDrain unvented Opening the gas valve 3.5 Connections diagram Start upStart up For a short time Shut downIntroduction You can Electrically isolateShut down Errors visible on the control ErrorsIntroduction Distinction is made between General errors Explosive ignition Symptom Cause Solution Remark Gas smellWater leakage Symptom Cause Solution Remark Insufficient or no Hot waterTroubleshooting table for errors visible on the control Light pulses Cause Solution RemarkLight pulses Cause Solution Remark SL3 See 12.2 Electrical circuit diagramTWI Maintenance Introduction Prepare maintenanceMaintenance 11.2 Warranty tank Warranty certificate11.1 Warranty general 11.3 Conditions11.7 Obligations Warranty certificate11.6 Claims SmithAnnex Electrical circuit diagram AnnexWiring Annex Index ConnectUser Warranty IndexPage 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.