Camus Hydronics 102 User Manual

PRODUCT DATA66-1171-03R7910A SOLA HC (Hydronic Control) R7911 SOLA SC (Steam Control)APPLICATIONThe R7910A SOLA HC is a hydronic boiler control system

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 10• Either ModBus RS485 communication port can be used to allow configuratio

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 100Speed up ramp Whenever the burner is firing it will be commanded to incre

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)101 66-1171—03Tap detect on hysteresisThe second tap demand “set” criteria depends on t

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 102APPENDIX B: HYDRONIC DEVICE PARAMETER WORKSHEET EXAMPLETable 50 is an exa

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)103 66-1171—03CH P gain Read Only 50 400CH I gain Read Only 50 400CH D gain Read Only 0

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 104Fan min duty cycle Read Only 10 100 0-100%CH pump output Read Only A:No p

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)105 66-1171—03Annunciator 4 location Read Only A:No annunciation for this terminalAnnun

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 106TROUBLESHOOTINGTo support the recommended Troubleshooting, the R7910 has

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)107 66-1171—03Table 51. R7910A Lockout and Hold Codes.Code Description Recommended Trou

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 1083 Internal fault: Hardware fault Internal Fault.1. Reset Module. 2. If fa

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)109 66-1171—0350 Modulation fault Internal sub-system fault. 1. Review alert messages f

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)11 66-1171—03Fig. 2. R7910A/R7911 dimensions in in. (mm). * All sensors attached to th

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 11080 DHW high limit 1. Check wiring and correct any possible errors. 2. Rep

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)111 66-1171—03101-104 RESERVEDFlame Operation Faults105 Flame detected out of sequence

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 112136 Interrupted Airflow Switch failed to close 1. Check wiring and correc

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)113 66-1171—03156 Combustion pressure and Flame ON OEM Specific1. Check that flame is n

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 114194 Invalid ignite failure response setting 1. Return to Configuration mo

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)115 66-1171—03239 Invalid S2 (J8-6) connector type setting L240 Invalid S5 (J8-11) conn

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 11646 Low line frequency occurred47 Invalid subsystem reset request occurred

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)117 66-1171—03CH parameter Errors131 CH demand source was invalid132 CH P-gain was inva

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 118209 Too many Lead Lag slaves were detected210 Lead Lag slave was discover

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)119 66-1171—03296 Abnormal Recycle: Interrupted air flow switch 297 Abnormal Recycle: I

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 12When Installing This Product…1. Read these instructions carefully. Failure

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 120381 Abnormal Recycle: Fan Speed Range Low382 Abnormal Recycle: Fan Speed

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)121 66-1171—03531 Mix PID setpoint was invalid532 STAT may not be a Mix demand source w

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)Automation and Control SolutionsHoneywell International Inc.1985 Douglas Drive NorthGol

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)13 66-1171—03Note that the high voltage ignition spark, the high voltage ignition lead

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 14Fig. 3. R7910A device pin out.3142FLAMESTRENGTHMB1A B CMB2A B CPOWERFL

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)15 66-1171—03Fig. 4. R7911 device pin out.3142FLAMESTRENGTHMB1A B CMB2A B CPOWERFLA

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 16Table 4. Recommended Grounding Practices.Ground Type Recommended PracticeE

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)17 66-1171—03J5 1 INTERLOCK Per Model Input RatingJ6 8 ALARM Input 24VAC, 120 VAC: 6.3

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 18a. Not used by R7911SC b. For single sensor 10K or 12K connect to TEMP A

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)19 66-1171—03STARTUPThe R7910A/R7911 is shipped in the unconfigured condition, so when

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 2FEATURESSafety and Boiler ProtectionR7910 Hydronic Control• Frost Protectio

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 20one or more of the items in the list. If a parameter is not listed in this

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)21 66-1171—03GENERAL CONFIGURATION SETTINGSThose that alter the behavior or availabilit

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 22Table 9. General Configuration Settings.Parameter CommentTemperature Units

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)23 66-1171—03Demand and RateThe Demand and Rate subsystem produces 3 outputs:• Pump dem

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 24Fig. 5. Demand and rate selection diagram.The demand priority control bloc

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)25 66-1171—03The burner demand priority control block implements a priority scheme acco

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 26The Hydronic Central Heating function is implemented as shown in Fig. 8.Fi

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)27 66-1171—03Outdoor Reset and BoostThe outdoor reset function is symmetrical for each

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 28setpoint is used. If TOD is on, the CH TOD setpoint provides the Y coordin

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)29 66-1171—03However, if the first boost event has not yet occurred, then the new setpo

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)3 66-1171—03Models Available:* Contains built in anticipation for Low Voltage Stat Inpu

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 30Fig. 11. Central heating steam diagram.The function of each parameter and

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)31 66-1171—03Setpoint and Hysteresis (Hydronic)The CH, DHW and LL master each have simi

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 32Whenever the burner turns off, the turn-on threshold is lowered by doublin

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)33 66-1171—03Fig. 13. Steam Setpoint and hysteresis. SETPOINT + OFF HYSTERESISSETPOINTS

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 34DHW Loop Demand and Rate (Hydronic only)The Domestic Hot Water (DHW) Deman

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)35 66-1171—03Table 13. Domestic Hot Water Parameters.Parameter CommentDHW demand switch

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 36Plate Heat ExchangerPlate heat exchanger demand for DHW comes from one of

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)37 66-1171—03Fig. 15. Plate heat exchanger subsystem.Table 14. Plate Heat Exchanger Par

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 38Preheat DemandTo ensure that the plate heat exchanger is ready, it maintai

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)39 66-1171—03Tap During PreheatAlthough preheat cannot become True while Tap demand is

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 4TABLE OF CONTENTSApplication ...

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 40Fig. 16. DHW storage.Table 17. DHW Storage Demand Parameters.Parameter Com

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)41 66-1171—03DHW Storage OperationWhen the DHW storage feature is enabled, whenever any

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 42Fig. 18. DHW frost protection.Table 18. CH Frost Protection Parameters.Par

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)43 66-1171—03Table 19. DHW Frost Protection Parameters.Parameter CommentDHW frost prote

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 44Rate Limits and OverrideThe Limit and Override subsystem consists of three

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)45 66-1171—03T-RiseA limit may be imposed on the rate of temperature rise for either th

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 46Heat Exchanger High LimitA temperature limit may be imposed on the exchang

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)47 66-1171—03Stack limit (Safety limit and Rate limit)STACK RATE LIMITIf the stack limi

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 48Thus there are 5 steps in the modulation limiting:step 0: unlimited (max i

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)49 66-1171—03Slow Start and Forced Rate limits (Hydronic Control)The Forced Rate limit

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)5 66-1171—03FEATURES, continuedAccess codes through the display allow for different lev

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 50DHW High Limit (Hydronic Control)If DHW high limit enable is enabled then

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)51 66-1171—03Anticondensation (Hydronic Control)The anticondensation function reduces c

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 52Fan Speed Modulation ParametersThese parameters are used only when fan spe

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)53 66-1171—03Analog Modulation ParametersThese parameters are used only when 4-20mA or

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 54PUMP CONTROLThere are six identical pump control blocks. Each has a differ

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)55 66-1171—03• Force On conditions: These bits enable or disable reasons why the pump m

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 56Pump ExercisingEach of the pumps (A, B, and C) will have an exercise timer

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)57 66-1171—03 The Burner Control Uses:InputsAll digital inputs are conditioned to elimi

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 58Table 33. Burner Control Safety Parameters.Parameter CommentNTC sensor typ

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)59 66-1171—03Fig. 23. Interrupted pilot.Purge rate proving None, High Fire Switch, Fan

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 6Non-Volatile MemoryThe R7910A/R7911 will store the following items in non-v

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 60Fig. 24. Intermittent pilot.Fig. 25. Direct burner ignitionTable 33. Burne

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)61 66-1171—03Main flame establishing period (MFEP)5, 10, or 15 SecondsThis parameter on

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 62ANNUNCIATORThe Annunciator section monitors the status of a series string

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)63 66-1171—03Fig. 26. Example of annunciator inputs and terminal names.SortingAnnunciat

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 64FAULT HANDLINGLockouts and AlertsThe R7910A implements two kinds of faults

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)65 66-1171—03BURNER CONTROL OPERATIONSafety Shutdown of Burner Control FunctionsSafety

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 66Central HeatingStart-up sequence central heating request (system in standb

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)67 66-1171—03CAUTIONEquipment Malfunction or Damage Hazard.Each device type is unique.

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 68c. On connector J5, jumper power to the ignition termi-nal J5 terminal 4.

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)69 66-1171—031. Open the master switch.2. Complete the normal ready-to-fire checkout of

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)7 66-1171—03• Transformer (for powering R7910/R7911 40va minimum) - AT72D (40VA) AT88 (

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 70NOTE: Low fuel pressure limits, if used, could be open. If so, bypass them

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)71 66-1171—03a. Add an orifice plate in front of the cell to restrict the viewing area

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 72SAFETY SHUTDOWN TESTS (ALL INSTALLATIONS) Perform these tests at the end o

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)73 66-1171—03energized, but if no voltage is detected at the terminal, the LED will be

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 74Next stage The SOLA that will or might be added as the next SOLA to fire.L

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)75 66-1171—03Fig. 28. S7999B system and lead lag wiring diagram.Lead-Lag OperationOEM C

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 76(1) As load increases:(a)Until all stages are firing - No stage is request

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)77 66-1171—03System Display ConfigurationThe following parameters are available for OEM

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 78Fig. 29. Master/Slave data transmission.Table 36. Slave Data Supporting Le

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)79 66-1171—03LL Master Operation and SetupLL master operation is subdivided into the fo

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 8Connectors for field wiring: May be obtained separately outside Honeywell.

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 80Periodic Data Polling MessagesThe LL master will poll to discover all the

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)81 66-1171—03OnLeave A slave in the OnLeave state remains that way until the ProcessSla

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 82Frost ProtectionLL master frost protection is enabled with the LL - Frost

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)83 66-1171—03ModulationFig. 31. Modulation.Modulation SensorWhen the burner demand is o

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 84SetpointsTIME OF DAYThe Time of Day has one sources of control: a switch c

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)85 66-1171—03RATE ADJUSTMENTWhen the LL - Slave dropout/return compensation parameter s

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 86OVERFLOW RATE AND UNDERFLOW RATEThe rate allocator knows the rate assigned

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)87 66-1171—03Adding StagesThe internal algorithms that generate AddStageRequests are ca

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 88Drop-stage MethodsError threshold For error threshold staging, a stage is

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)89 66-1171—03• If this parameter is “Measured run time” then they are ordered according

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)9 66-1171—03OVERVIEWFunctions provided by the R7910A/R7911 include automatic boiler seq

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 90Sequencer Drop Lag Boiler SelectionWhen the stager asks the sequencer for

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)91 66-1171—03APPENDIX A: PARAMETER GLOSSARYR7910A parameter glossary can be found in Ta

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 92Annunciator mode The annunciator may be fixed, in which the labels and loc

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)93 66-1171—03CH enable This parameter determines whether the CH loop is enabled or disa

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 94CH slow start enableThis parameter enables or disables the slow start limi

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)95 66-1171—03DHW high limit responseIf Recycle && hold is selected, the burner

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 96Exchanger T-Rise enableThis enables/disables temperature rise detection fo

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)97 66-1171—03ILK bounce detection enableEnable, Disable 58ILK long name The long name (

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)66-1171—03 98LL - Slave write This allows the slave to accept command messages from a S

R7910A SOLA HC (HYDRONIC CONTROL) R7911 SOLA SC (STEAM CONTROL)99 66-1171—03Plate preheat off hysteresisThe preheat off threshold is calculated as:TOF