Bosch Appliances WR430-7K manual Pressure Regulation, Temperature Regulation

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PRESSURE REGULATION

The pressure regulator supplied with the water heater is adjusted to operate on the gas specified on the rating plate and:

in Canada, is factory preset to deliver gas at the high altitude setting listed on the rating plate and as shown below.

in the U.S.A., is factory preset to deliver gas at the standard altitude setting listed on the rating plate and as shown below.

The pressure setting of the gas pressure regulator should be checked at installation to assure that the setting is correct for the gas being used and the altitude at which the appliance is installed. See rating plate on the unit, Table 1, below, for proper setting.

In Canada, for a heater being installed at standard altitude (0-2,000 ft above sea level) the manifold pressure should be reset at installation to the value shown on the rating plate, or Table 1, below, for standard altitude.

REGULATOR

SUPPLY TEST

PRESSURE TAP T

ADJUSTABLE

PRESSURE REGULATOR

Figure 10

The gas pressures specified below refer to flow pressure taken at the pressure tap in the gas inlet pipe just above the pressure regulator, (see figure 10) while the heater is operating at full input.

Gas pressures read at burner test point D (see fig. 7) page 13.

Table 1.

Appliance Regulator Pressure Setting

Model

Type of Gas

Pressure tap

Altitude

 

 

kPa

Inches, W.C.

 

 

 

 

 

 

 

 

 

natural

1.41

5.38

standard

 

 

 

 

 

WR430-7K

propane

2.61

9.9

(0-2,000 ft.)

 

 

 

 

natural

1.14

4.4

high*

 

 

 

 

 

 

 

propane

2.09

7.9

(2,000-4,500 ft.)

 

 

 

 

 

*Note: The high altitude ratings listed are Canadian Gas Association high altitude ratings for the appliances and are only valid in Canada. In the U.S.A. the National Fuel Gas Code, ANSI 1- 1988, recommends for high altitude installations, above 2,000 feet, that the input rate be reduced 4% for each 1,000 feet above sea level.

Your appliance dealer and/or your local gas supplier should be consulted in regard to any high altitude installation. If field adjustment is required it should be performed by a qualified serviceman experienced in such work.

TEMPERATURE REGULATION

The BOSCH WR430-7K is equipped with a modulating gas valve which adjusts the flow of gas to the main burner in proportion to the water flow rate. Within its heating capacity the WR430-7K attempts to maintain the set temperature rise across the heater. This temperature rise can be set in range of 25°C - to - 50°C (45°F - to - 90°F), by means of the water flow selector. See Figure 11. When the water flow selector is turned to the right hand stop the water heater is set for 50°C (90°F) temperature rise; when the water flow selector is set to the left hand stop it is set for 25°C (45°F) temperature rise.

Temperature Adjustment Knob

Decreases temperature

Increases temperature

and increases flow

and decreases flow

Figure 11 - Principles of Operation

With the water flow selector turned to its right hand stop position (50°C rise setting) and with an inlet water temperature of 10°C (50°F) the outlet water temperature will be maintained at approximately 60°C (140°F) in the water flow rate range of approximately 2 litres/min. (0.5 U.S. gals./min.) to 9.5 litres/min. (2.5 U.S. gals./min.).

The minimum flow rate for operation, the “Threshold Flow Rate” referred to in the lighting instructions is 2 litres/min (0.5 U.S. gals./min.). If the water flow rate is below this level the main burner will not fire. If the flow rate exceeds 9.5 litres/min (2.5 U.S. gals./min.) the temperature rise aross the heater will decrease in proportion to the rate above this temperature.

HIGH TEMPERATURE LIMIT SWITCH

The BOSCH series instantaneous gas water heaters are equipped with a high temperature limit switch with a set point of approximately 90°C (195°F). If the water temperature at the sensing points exceeds the set point the switch will open, interrupting the safety circuit and stopping gas flow to the pilot and main burner.

Outage as the result of high limit operation indicates that the heater is not functioning properly. The heater should be checked by a qualified serviceman and the reason for the malfunction is corrected.

6 720 606 599

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Contents What to do if YOU Smell GAS Instantaneous gas water heaterFeatures Unpacking the Bosch WR430-7K HeaterNAT. GAS Propane Dimensions Location ElectricalAIR Requirements Mounting ClearanceSizing & Distances IntroductionGeneral Information General Venting InformationApproved Venting Materials General Code RequirementsVent Terminal Installation Electrical Wiring Vent InstallationOperation and Checking the Draft Vent InstallationMaintenance Water Connections Drip TrayGAS Connections Relief ValveTo Turn OFF GAS to Appliance Service HintFilling Lighting and Operating InstructionsTemperature Regulation High Temperature Limit SwitchPressure Regulation Characteristic Pilot Flame Maintenance and ServiceTrouble Shooting Adjusting ScrewNo Spark AT the Pilot Pilot Sparks Continuously with No Water Running Pilot Lights but Burners Will not Come onMain Burners GO OUT During HOT Water USE Water is TOO HOT Water is not HOT EnoughHOT Water Tempe Ratur E Fluctuates Diagram of WR430-7K 720 606 Interior Components Diagram Parts List WR430 Interior Components Diagram and Parts List Page Chauffe-eau instantané, à gaz Principe de fonctionnement Déballage DU CHAUFFE-EAU Bosch WR430-7KDimensions Lieu Dinstallation Alimentation ÉlectriqueDemande Dair Avertissement Dégagements DE SéparationMontage Information Générale IntroductionPrescriptions Générales DES Codes Matériaux Approuvés Pour LE Circuit DE DéchargeInstallation DE LA Bouche DE Décharge Câblage Électrique Installation DU Système DE DéchargeContrôle DU Tirage Utilisation ET Contrôle DU TiragePoints dinspection EntretienRaccordement AUX Canalisations Deau Plateau DE RécupérationRaccordement À LA Canalisation DE GAZ Soupape DE SurpressionRemplissage Allumage ET UtilisationInterruption DE L’ALIMENTATION EN GAZ DU CHAUFFE-EAU Thermostat DE Sécurité «HAUTE TEMPÉRATURE» Régulation DE LA PressionDispositif de la flamme de veille PAS D’ÉTINCELLES Pour LA Flamme DE Veille DépannageFlamme DE Veille ALLUMÉE, Mais LE Brûleur NE ’ALLUME PAS Production Constante D’ÉTINCELLES, Sans Circulation D’EAUEAU Trop Chaude Température DE L’EAU InsuffisanteFluctuation DE LA Température DE L’EAU Chauffe-eau WR430-7K 720 606 Composants Internes DU CHAUFFE-EAU WR ET Liste DES Pièces Composants Internes ET Liste DES Pièces