Lochinvar 90, 500 service manual Water Chemistry, Softened Water Systems, Pump Operation

Page 47

Installation & Service Manual

7Domestic water heaters (continued)

Water Chemistry

The required temperature rise and the standard pump sizing are based on the heating of potable water with chemistry within the specified limits. Caution should be used when heating water softened to less than 5 grains per gallon. Many commercial water softeners reduce hardness to 0 grains which may result in long term problems in the system. Softened water will usually have a lower pH which can be aggressive and corrosive causing non-warrantable damage to the heater, pump, and associated piping.

Corrosion due to water chemistry generally shows up first in the hot water system because heated water increases the rate of corrosive chemical reactions. As water is heated it becomes less soluble. The dissolved minerals and solids will precipitate and collect as scale if water velocity is not properly controlled. Follow the temperature rise requirements for unsoftened water. Consult the manufacturer when heating potable water with hardness or total dissolved solids exceeding these specifications. Heating of high hardness and/or high total dissolved solids water may require a larger circulating pump, an optional cupro-nickel heat exchanger and a revised temperature rise specification based on the water chemistry of the water to be heated.

Softened Water Systems

Decreasing the flow rate will reduce the erosion process, however the heat exchanger should be monitored to ensure the scale/liming process is not made worse. The unit should be placed on a comprehensive inspection schedule until optimum flow rates can be established. Problematic water areas may require heat exchanger inspection every two weeks. The total scale accumulation should never exceed the thickness of a piece of paper. Should scale accumulation exceed this thickness the flow rate will need to be increased. The tubes should not have a bright shiny copper look. This would indicate that the erosion process has begun and the flow rate will need to be decreased. Once the proper flow rates have been established the inspection intervals can be increased to every 30 days, once a quarter, or to a bi-annual inspection. This procedure should ensure proper operation of the unit as long as the water quality stays consistent.

TABLE - 7B

COMMON WATER MANIFOLD SIZE FOR MULTIPLE HOT WATER SUPPLY BOILER INSTALLATIONS

Pipe sizing chart provides minimum pipe size for common manifold piping and tank tappings to ensure adequate flow.

 

Number of Units

Common Manifold Size (Min.)

 

 

 

 

 

 

1

2"

 

 

 

 

 

 

2

2"

 

 

 

 

 

 

3

2 1/2"

 

 

 

 

 

 

4

3"

 

 

 

 

 

 

5

3 1/2"

 

 

 

 

 

 

6

3 1/2"

 

 

 

 

 

Pump Operation

1.The water heater/hot water supply boiler must be connected to a properly sized pump that circulates water between the heater and storage tank.

2.A standard water heater is furnished with a 1/6 HP, 120 VAC, 3.6 AMP circulating pump to be mounted on the units inlet water connection. This pump is sized based on

installation of a single storage tank and heater in close

proximity. If the number of fittings and straight pipe exceeds the quantities shown in this section, a larger pump will be required.

3.The pump must run continuously when the burners are firing.

4.Lubricate the pump to the manufacturers recommendations. Pump damage due to inadequate lubrication is non-warrantable.

5.Pump is sized to heater input and water hardness. Care should be taken to size the pump correctly. See “Water Chemistry”, this page.

The standard pump selection is based on the following pipe and fittings from the unit to the storage tank:

6

- 90° elbows

2 - ball valves

2

- unions

1 - cold water tee

Plus the following length of straight pipe based on the heater size:

90,000 through 360,000 Btu/hr Models Not more than 45 feet of straight pipe

399,999 through 500,000 Btu/hr Models Not more than 25 feet of straight pipe

For every elbow and tee in excess of those shown above, DEDUCT 5 FEET from maximum allowable straight pipe in heater to tank circulating loop.

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Contents Models 90,000 500,000 Btu/hr Contents Checking equipment Please read before proceedingCodes Copper-fin =B=R Rating RatingsCopper-fin Specifications Gas connection pipe Copper-fin How it worksModels CWN270 Front View Model CWN399 Front View 422 Location of unit Determine unit location3Combustion Air Direct from Outside Determine boiler location6Combustion Air from Outside Single Opening Minimum Recommended Combustion AIR Supply to Equipment Room Vent Pipe Sizes VentingConventional Negative Draft Venting System Venting Less from Ridge From Parapet Wall Vertical Vent Termination ClearancesNumber Masonry Chimney InstallationVent Materials Sidewall Venting7CB with Vent Damper and Vent Damper Terminal Block Automatic Vent DamperManifold Pressure Gas connectionsGas Supply Gas Pressure Test Gas ConnectionGas Piping Install Piping to ControlClockwise to raise regulator gas pressure, counterclockwise Gas Manifold Pressure Adjustment Procedure4Gas Supply Pressure Checking Gas Supply PressureTwo Stage Burner Control System Combination Gas ValvesVenting of Combination Gas Valves Relief Valve Water Flow Switch if equippedHydronic piping General Plumbing Rules Typical Heating Boiler InstallationsLow Water Cutoff if equipped Minimum Required Flow For Heating BoilerPiping of the Boiler System System Temperature Rise ChartCirculator Pump Requirements Heat Exchanger Pressure Drop ChartCirculator Pump Specifications Water Connections Heating Boilers OnlyPrimary/Secondary Boiler Piping Boiler Flow Rates Three Way Valves4Primary / Secondary Piping of a Single Boiler Primary / Secondary PipingNot to Exceed 4 Pipe DIA or MAX. of 12 Apart 8Multiple Boilers Zoned with Circulators Electrical connections Terminal Strip WiringBoiler Operating Temperature Control Power Venter Connection to Terminal StripOperating Temperature Control Temperature AdjustmentPump Wiring for a Heating Boiler Maximum Set Point Determination Locating Temperature ControlTemperature Control Settings Maximum SET Point DeterminationOutdoor Air Temperature Sensor Temperature Control SensorsInlet Water Temperature Sensor Multi-Purpose Temperature SensorInstallation of a Tank Sensor Water Heater Application Outdoor Air Reset OptionInstallation of a Remote Sensor Boiler Application Additional Temperature Controls Manual Reset High Water Temperature Limit Control Blocked Vent and Flame Roll-Out / Flame Interlock SwitchInitial Start-up Pre-start ChecklistStart-up 1Gas Valve 90,000 270,000 Btu/hr Models Lighting InstructionsTo Turn OFF GAS to Appliance Safety Shutoff Test For Standing Pilot Ignition SystemOperating Instructions To Turn Off Gas to Appliance Safety Shutoff Test for Spark Ignition Pilot SystemIntermittent Pilot Spark Ignition System F9/M9 Freeze ProtectionFreeze Protection for a Heating Boiler System if required Water TreatmentDomestic Water Heaters 90,000 500,000 Btu/hr Models Required Temperature RiseRequired Temperature Rise Domestic water heatersPump Operation Water ChemistrySoftened Water Systems 1Single water heatersingle tank 2Single water heatermultiple tank 3Multiple water heatersingle tank Heat Exchanger Remote Sensor InstallationThermostat Settings Minimum Pump Performance5Danger Warning Cathodic Protection Water Flow Switch if equippedPressure Only Relief Valve Thermal ExpansionSee the User’s Information Manual for instructions Maintenance and annual startupService technician Owner maintenanceMaintenance Check Relief Valve Check Expansion TankPerform Start-up and Checks Check All WiringCheck Control Settings Combustion Air AdjustmentInspection and Cleaning Procedure Inspect and Clean BurnerHeat Exchanger / Burner Access Water Circulating Pump Pilot Flame Adjustment ProcedureClear Area Inspection of Heat Exchanger WaterwaysGas Train and Controls Review with ownerTroubleshooting Pilot or replace 90,000 270,000 Btu/hr Models DiagramsSchematic Diagram F1 Unit Wiring Diagram F1 Unit315,000 399,999 Btu/hr Models Schematic Diagram F9 UnitWiring Diagram F9 Unit Diagrams Diagrams Page Revision a ECO #C06290 initial release CFA-I-S Rev a 09/10
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