RBI FlexCore CK 850 Control Manual

Also see for FlexCore CK 1000: Installation and operation instructions

Contents

RBI FlexCore CK 850 Control Manual Manual pdf 12 page image

SETUP & OPERATIONPage 12SETUP & OPERATIONBasic Multi Boiler System OperationFor boiler system setup/installationsplease refer to the 2008 ASHRAE Handbook, CH12 or laterrevision.A basic multi boiler system typically uses boilers of thesame size and type. With HeatNet, this includes (1) Masterand (1-15) Member boilers. The boilers are connectedtogether using an H-Net communications cable effectivelycreating (1) boiler. This allows the system heating BTUs tobe evenly distributed amongst all of the boilers.The Version 1.6 HeatNet board requires Minibusconnections for FlexCore boilers with more than (1) heatexchanger. The Minibus requires a serial data cable betweeneach HeatNet Control board. The first and last HeatExchanger must have the minibus terminated for the bus towork properly. S1 would be placed in the ON position asindicated below for the front and rear heat exchangers. Thejumper, JS1 must always be in the position indicated(closest to S1). It is used for testing.Basic multiple boiler systemA basic multi boiler system can be configured using theboiler menus to create custom systems/features. Thesefeatures are best described in the section: Default Settings& Menu Item Description. Along with these menu itemsare hardware support for many auxiliary functions.Once the system has been properly setup (all default menuvalues used and H-Net addresses assigned), the system isenabled by placing the REMOTE/LOCAL switch to theLOCAL position on the Master boiler. All Member boilersmust have their respective switches in the REMOTEposition. When the Master boiler’s Heat Demand input(LOCAL switch) closes, the system becomes operationaland will fire as many boilers as it needs to maintain theheader water temperature’s setpoint. See the DHW sectionto fire using two setpoints.When a boiler is to be fired in a multi boiler system (headerwater temperature is below the heating band), the Masterchecks the HeatNet boilers it has available. Then the Masterchecks if a Lead Boiler is to be used (LEAD BOILER > 0).The Master boiler then looks at which type of firing rotationit has selected: LOFO, FOFO, TRUE (runtime), or MIXED.In our example we will use the TRUE (runtime) rotationsince it is the default.The Master now checks all of the runtimes to determinewhich boiler has the least runtime based on the MINRUNTIME setting in SETTINGS: FIRING MODE: TheMIN RUNTIME setting is the minimum runtime interval inhours that is used to compare boiler to boiler runtimes.Once the boiler designated to fire has been determined, theMaster sends the command over the H-Net cable to fire thatboiler and resets the ADD BOILER delay timer to preparefor the next boiler to fire. If the header water temperature isstill below the heating band and the ADD BOILER delaytimer has expired to zero, the process is repeated until theheader water temperature enters the heating band.When a boiler receives a command to fire:NOTE: Runtime messages are displayed in the lower leftcorner of the Home Screen. See Section Messages fordescriptions.1. The system pump relay is enabled and the H-Netcontrol displays “Waiting for Flow” until the flow-switch closes between J11A, 1 & 2 within theprogrammed time (10 seconds default).2. All elements in the interlock string, terminated betweenJ11A and J11B, must be closed before the sequence isallowed to continue.3. If all interlocks are closed, relay K5 is enabled tocommand the combustion-air damper open (if used).The H-Net control displays “Waiting for Damper toOpen” until the damper end switch closes.4. Relay K6 is enabled energizing the local pump (ifused). The H-Net control commences its Waiting for1 to 16 BoilersMember BoilersMaster