Honeywell SOLA R7910 hydronic/steam control

Register map(s) for this device, with a note of how far each has been checked. Addresses are 0-based, as on the wire. Scale and byte order are confirmed only at the hardware-verified rung.

coherence-checked

Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.

point	address (0-based)	type	scale	unit
Status Change	0	U16	1
Configuration Change	1	U16	1
Digital I/O	2	U16	1
Annunciation I/O	3	U16	1
Limits	4	U16	1
Program Module (PM) status	5	U16	1
Demand source	6	U16	1
Outlet (S3S4) or Outlet limit (S3) sensor	7	U16	0.1	°C
Firing rate	8	U16	1	% or RPM
Fan speed	9	U16	1	RPM
Flame signal	10	U16	0.01	V or μA
Inlet (S1) sensor	11	U16	0.1	°C
DHW (S6S7) or DHW limit (S6) sensor	12	U16	0.1	°C
S5 sensor	13	U16	0.1	°C
Stack (S8S9) or Stack limit (S8) sensor	14	U16	0.1	°C
4-20 mA remote control input (S2) terminal	15	U16	0.1	mA
Active CH setpoint	16	U16	0.1	°C
Active DHW setpoint	17	U16	0.1	°C
Active LL setpoint	18	U16	0.1	°C
Register Access Status	19	U16	1
Steam pressure	20	U16	0.1	psi
Analog modulation input	21	U16	0.1	mA
Active CH pressure setpoint	22	U16	0.1	psi
Extended Status Change	23	U16	1
Active CH operating point	25	U16	0.1	°C
Active DHW operating point	26	U16	0.1	°C
Active Lead Lag operating point	27	U16	0.1	°C
Active system operating point	28	U16	0.1	°C
Active system setpoint	29	U16	0.1	°C
Active system on hysteresis	30	U16	0.1	°C
Active system off hysteresis	31	U16	0.1	°C
Burner control status	32	U16	1
Burner control state	33	U16	1
Lockout code	34	U16	1
Alarm reason	35	U16	1
Annunciator first out	36	U16	1
Annunciator hold	37	U16	1
Sequence time	38	U16	1	s
Delay time	39	U16	1	s
Hold code	40	U16	1
Burner control flags	41	U16	1
CH remote Stat	42	U16	1
Outlet operation (S4=J8-10) terminal	43	U16	0.1	°C
DHW operation (S7=J9-3) terminal	44	U16	0.1	°C
Stack or Heat exchanger operation (S9=J9-6) terminal	45	U16	0.1	°C
Outlet operation sensor (S4=J8-10) state	46	U16	1
DHW operation sensor (S7=J9-3) state	47	U16	1
Outlet limit sensor (S3=J8-8) state	48	U16	1
Inlet sensor (S1=J8-4) state	49	U16	1
DHW limit sensor (S7=J9-1) state	50	U16	1
Stack limit sensor (S8=J9-4) state	51	U16	1
S5 (J8-11) sensor state	52	U16	1
4-20mA remote control input (S2=J8-6) state	53	U16	1
Pressure sensor (S1=J8-4) state	54	U16	1
Stack operation or Heat exchanger sensor (S9=J9-6) state	55	U16	1
Active rate limiter	56	U16	1
Limited rate	57	U16	1	RPM or %
Active rate override	58	U16	1
Override rate	59	U16	1	RPM or %
Demand rate	60	U16	1	RPM or %
Active system sensor	61	U16	1
Active Lead Lag sensor	62	U16	1
CH status	64	U16	1
CH setpoint source	65	U16	1
CH heat demand	66	U16	1
CH burner demand	67	U16	1
CH requested rate	68	U16	1	RPM or %
CH frost heat demand	69	U16	1
CH frost burner demand	70	U16	1
Active CH on hysteresis	71	U16	0.1	°C
Active CH off hysteresis	72	U16	0.1	°C
Active CH pressure on hysteresis	73	U16	0.1	psi
Active CH pressure off hysteresis	74	U16	0.1	psi
Active CH pressure operating point	75	U16	0.1	psi
Active CH sensor	76	U16	1
Heat Demand	77	U16	1
BURNER DEMAND	78	U16	1
Active DHW sensor	79	U16	1
DHW status	80	U16	1
DHW setpoint source	81	U16	1
DHW priority count	82	U16	1	s
DHW heat demand	83	U16	1
DHW burner demand	84	U16	1
DHW requested rate	85	U16	1	RPM or %
DHW frost heat demand	86	U16	1
DHW frost burner demand	87	U16	1
Active DHW on hysteresis	88	U16	0.1	°C
Active DHW off hysteresis	89	U16	0.1	°C
DHW storage time	90	U16	1	s
DHW storage heat demand	91	U16	1
DHW storage burner demand	92	U16	1
Pump A status	93	U16	1
Pump B status	94	U16	1
CH pump start delay time	95	U16	1	s
CH pump status	96	U16	1
CH pump overrun time	97	U16	1	s
CH FP overrun time	98	U16	1	s
CH pump idle days count	99	U16	1	days
DHW pump status	100	U16	1
DHW pump start delay time	101	U16	1	s
DHW pump overrun time	102	U16	1	s
DHW FP overrun time	103	U16	1	s
DHW pump idle days count	104	U16	1	days
System pump status	105	U16	1
System pump overrun time	106	U16	1	s
System pump idle days count	107	U16	1	days
Boiler pump status	108	U16	1
Boiler pump overrun time	109	U16	1	s
Boiler pump idle days count	110	U16	1	days
Auxiliary 1 pump status	111	U16	1
Auxiliary 1 pump idle days count	112	U16	1	days
Auxiliary 2 pump status	113	U16	1
Auxiliary 2 pump overrun time	114	U16	1	s
Auxiliary 2 pump idle days count	115	U16	1	days
Auxiliary 1 pump overrun time	119	U16	1	s
Burner cycle count	128	U32BE	1
Burner run time	130	U32BE	1	h
CH pump cycle count	132	U32BE	1
DHW pump cycle count	134	U32BE	1
System pump cycle count	136	U32BE	1
Boiler pump cycle count	138	U32BE	1
Auxiliary pump cycle count	140	U32BE	1
Controller cycle count	142	U32BE	1
Controller run time	144	U32BE	1	h
Auxiliary 2 pump cycle count	146	U32BE	1
Auxiliary 2 pump start delay time	148	U16	1	s
Boiler pump start delay time	149	U16	1	s
System pump start delay time	150	U16	1	s
Auxiliary 1 pump start delay time	151	U16	1	s
DHW tap heat demand	152	U16	1
DHW preheat demand	153	U16	1
DHW change rate	154	U16	0.1	°C/s
DHW tap on recognition time	155	U16	1	s
DHW tap on time	156	U16	1	s
DHW preheat delay after tap time	157	U16	1	s
DHW preheat on recognition time	158	U16	1	s
DHW preheat on time	159	U16	1	s
Lead Lag master status	160	U16	1
Lead Lag slave status	161	U16	1
Lead Lag master setpoint source	162	U16	1
Lead Lag master heat demand	163	U16	1
Lead Lag slave burner demand	164	U16	1
Lead Lag slave requested rate	165	U16	1	RPM or %
Active Lead Lag on hysteresis	166	U16	0.1	°C
Active Lead Lag off hysteresis	167	U16	0.1	°C
Pump C status	168	U16	1
Outdoor temperature	170	U16	0.1	°C
Outdoor sensor state	171	U16	1
Outlet T-rise rate	172	U16	0.1	°C/s
Exchanger T-rise rate	173	U16	0.1	°C/s
S10 sensor reading	174	U16	0.1	°C
S10 sensor state	175	U16	1
Product type	176	U16	1
Password	177	U16	1
Temperature units	178	U16	1
Antishort cycle time	179	U16	1	s
Alarm silence time	180	U16	1	min
Power up with lockout	181	U16	1
Reset and restart	182	U16	1
Burner name	183	U16	1
Installation data	184	U16	1
OEM ID	185	U16	1
OS number	186	U16	1
Date code	187	U16	1
Safety microprocessor build	188	U16	1
Application microprocessor build	189	U16	1
Installer password	190	U16	1
OEM password	191	U16	1
Modulation output	192	U16	1
CH maximum modulation rate	193	U16	1	RPM or %
DHW maximum modulation rate	194	U16	1	RPM or %
Minimum modulation rate	195	U16	1	RPM or %
Prepurge rate	196	U16	1	RPM or %
Lightoff rate	197	U16	1	RPM or %
Postpurge rate	198	U16	1	RPM or %
CH forced rate	199	U16	1	RPM or %
CH forced rate time	200	U16	1	s
DHW forced rate	201	U16	1	RPM or %
DHW forced rate time	202	U16	1	s
Burner switch	203	U16	1
Firing rate control	204	U16	1
Manual firing rate	205	U16	1	RPM or %
Analog output hysteresis	206	U16	1
Standby rate	207	U16	1	RPM or %
CH enable	208	U16	1
CH demand switch	209	U16	1
CH modulation sensor	210	U16	1
CH setpoint	211	U16	0.1	°C
CH time of day setpoint	212	U16	0.1	°C
CH on hysteresis	213	U16	0.1	°C
CH off hysteresis	214	U16	0.1	°C
CH outdoor reset enable	215	U16	1
CH P-gain	216	U16	1
CH I-gain	217	U16	1
CH D-gain	218	U16	1
CH hysteresis step time	219	U16	1	s
CH pressure setpoint	220	U16	0.1	psi
CH pressure on hysteresis	221	U16	0.1	psi
CH pressure off hysteresis	222	U16	0.1	psi
Ignition source	224	U16	1
BLR/HSI function	225	U16	1
Igniter on during	226	U16	1
Pilot type	227	U16	1
Flame sensor type	228	U16	1
Purge rate proving	229	U16	1
Lightoff rate proving	230	U16	1
Prepurge time	231	U16	1	s
Pre-ignition time	232	U16	1	s
Pilot flame establishing period (PFEP)	233	U16	1
Main flame establishing period (MFEP)	234	U16	1	s
Run stabilization time	235	U16	1	s
Postpurge time	236	U16	1	s
Interlock start check enable	237	U16	1
Interlock open response	238	U16	1
Ignite failure response	239	U16	1
Ignite failure retries	240	U16	1
Ignite failure delay	241	U16	1	s
MFEP flame failure response	242	U16	1
Run flame failure response	243	U16	1
Pilot test hold	244	U16	1
Interrupted air switch (IAS) enable	246	U16	1
IAS start check enable	247	U16	1
LCI enable	248	U16	1
PII enable	249	U16	1
Flame threshold	250	U16	0.1	μA
ILK/LCI bounce detection	253	U16	1
Forced recycle interval time	254	U16	1	min
Fan speed error response	255	U16	1
Absolute maximum fan speed	256	U16	1	RPM
Absolute minimum fan speed	257	U16	1	RPM
Fan PWM frequency	258	U16	1
Fan pulses per revolution	259	U16	1
Fan speed-up ramp	260	U16	1	RPM/s
Fan slow-down ramp	261	U16	1	RPM/s
Fan gain up	262	U16	1
Fan gain down	263	U16	1
Fan minimum duty cycle	264	U16	1	%
DHW upper modulation sensor	270	U16	1
DHW lower modulation sensor	271	U16	1
CH pump output	272	U16	1
CH pump control	273	U16	1
CH pump overrun time	274	U16	1	s
CH FP pump overrun time	275	U16	1	s
DHW pump output	276	U16	1
DHW pump control	277	U16	1
DHW pump overrun time	278	U16	1	s
DHW FP pump overrun time	279	U16	1	s
DHW pump start delay	280	U16	1	s
Boiler pump output	281	U16	1
Boiler pump control	282	U16	1
Boiler pump overrun time	283	U16	1	s
Auxiliary 1 pump output	284	U16	1
Auxiliary 1 pump control	285	U16	1
System pump output	287	U16	1
System pump control	288	U16	1
System pump overrun time	289	U16	1	s
Pump exercise interval	290	U16	1	days
Pump exercise time	291	U16	1	s
CH pump start delay	292	U16	1	s
Boiler pump start delay	293	U16	1	s
System pump start delay	294	U16	1	s
Auxiliary 1 pump start delay	295	U16	1	s
CH pump options 1	296	U16	1
CH pump options 2	297	U16	1
DHW pump options 1	298	U16	1
DHW pump options 2	299	U16	1
Boiler pump options 1	300	U16	1
Boiler pump options 2	301	U16	1
System pump options 1	302	U16	1
System pump options 2	303	U16	1
Annunciation enable	304	U16	1
Annunciator mode	305	U16	1
Annunciator 1 configuration	306	U16	1
Annunciator 2 configuration	319	U16	1
Annunciator 3 configuration	332	U16	1
Annunciator 4 configuration	345	U16	1
Annunciator 5 configuration	358	U16	1
Annunciator 6 configuration	371	U16	1
Annunciator 7 configuration	384	U16	1
Annunciator 8 configuration	397	U16	1
PII configuration	410	U16	1
LCI configuration	422	U16	1
ILK configuration	434	U16	1
DHW enable	448	U16	1
DHW demand switch	449	U16	1
DHW priority vs CH	450	U16	1
DHW priority vs LL	451	U16	1
DHW priority time	452	U16	1	s
DHW setpoint	453	U16	0.1	°C
DHW time of day setpoint	454	U16	0.1	°C
DHW on hysteresis	455	U16	0.1	°C
DHW off hysteresis	456	U16	0.1	°C
DHW P-gain	457	U16	1
DHW I-gain	458	U16	1
DHW D-gain	459	U16	1
DHW hysteresis step time	460	U16	1	s
DHW modulation sensor	461	U16	1
DHW priority source	463	U16	1
Outlet high limit setpoint	464	U16	0.1	°C
Outlet high limit response	465	U16	1
Stack limit enable	466	U16	1
Stack limit setpoint	467	U16	0.1	°C
Stack limit response	468	U16	1
Stack limit delay	469	U16	1	s
Delta-T inlet/outlet enable	470	U16	1
Delta-T inlet/outlet degrees	471	U16	0.1	°C
Delta-T response	472	U16	1
Delta-T delay	473	U16	1	s
DHW high limit enable	474	U16	1
DHW high limit setpoint	475	U16	0.1	°C
DHW high limit response	476	U16	1
CH slow start enable	477	U16	1
DHW slow start enable	478	U16	1
Slow start ramp	479	U16	1
Slow start setpoint	480	U16	0.1	°C
Outlet T-rise enable	481	U16	1
Outlet T-rise degrees	482	U16	0.1	°C/min
Outlet T-rise delay	483	U16	1	s
Outlet high limit enable	484	U16	1
Delta-T retry limit	485	U16	1
Delta-T rate limit enable	486	U16	1
Delta-T inverse limit time	487	U16	1	s
Delta-T inverse limit response	488	U16	1
Delta-T exchanger/outlet enable	489	U16	1
Delta-T exchanger/outlet degrees	490	U16	0.1	°C
Exchanger T-rise enable	491	U16	1
T-rise response	492	U16	1
T-rise retry limit	493	U16	1
Delta-T inlet/exchanger enable	494	U16	1
Delta-T inlet/exchanger degrees	495	U16	0.1	°C
CH anticondensation enable	496	U16	1
CH anticondensation setpoint	497	U16	0.1	°C
DHW anticondensation enable	499	U16	1
DHW anticondensation setpoint	500	U16	0.1	°C
Anticondensation priority	502	U16	1
Frost protection anticondensation enable	503	U16	1
DHW storage enable	504	U16	1
DHW storage time	505	U16	1	s
DHW storage setpoint	506	U16	0.1	°C
DHW storage on hysteresis	507	U16	0.1	°C
DHW storage off hysteresis	508	U16	0.1	°C
DHW priority method	509	U16	1
DHW DEMAND ON TEMPERATURE	510	U16	1
DHW DEMAND OFF TEMPERATURE	511	U16	1
CH ODR maximum outdoor temperature	512	U16	0.1	°C
CH ODR minimum outdoor temperature	513	U16	0.1	°C
CH ODR low water temperature	514	U16	0.1	°C
CH ODR boost time	515	U16	1	s
CH ODR boost maximum off point	516	U16	0.1	°C
Lead Lag CH ODR maximum outdoor temperature	517	U16	0.1	°C
Lead Lag CH ODR minimum outdoor temperature	518	U16	0.1	°C
Lead Lag CH ODR low water temperature	519	U16	0.1	°C
Lead Lag CH ODR boost time	520	U16	1	s
Lead Lag CH ODR boost maximum off point	521	U16	0.1	°C
CH ODR boost step	522	U16	0.1	°C
Minimum boiler water temperature	526	U16	0.1	°C
Lead Lag CH ODR minimum water temperature	527	U16	0.1	°C
CH frost protection enable	528	U16	1
DHW frost protection enable	529	U16	1
Outdoor frost protection setpoint	530	U16	0.1	°C
Lead Lag frost protection enable	532	U16	1
Lead Lag frost protection rate	533	U16	0.1	%
IAS open modulation enable	536	U16	1
IAS open rate differential	537	U16	1
IAS open modulation step rate	538	U16	1
IAS open modulation step time	539	U16	1	s
IAS closed response	540	U16	1
CH minimum pressure	541	U16	0.1	psi
CH time of day pressure setpoint	542	U16	0.1	psi
Analog input hysteresis	543	U16	0.1	mA
Lead Lag slave enable	544	U16	1
Lead Lag master enable	545	U16	1
Lead Lag setpoint	546	U16	0.1	°C
Lead Lag time of day setpoint	547	U16	0.1	°C
Lead Lag outdoor reset enable	548	U16	1
Lead Lag on hysteresis	549	U16	0.1	°C
Lead Lag off hysteresis	550	U16	0.1	°C
Lead Lag hysteresis step time	551	U16	1	s
Lead Lag P-gain	552	U16	1
Lead Lag I-gain	553	U16	1
Lead Lag D-gain	554	U16	1
Lead Lag operation switch	555	U16	1
Lead Lag CH demand switch	556	U16	1
Lead Lag CH setpoint source	557	U16	1
Lead Lag modulation sensor	558	U16	1
Lead Lag modulation backup sensor	559	U16	1
Lead Lag CH 4 mA water temperature	560	U16	0.1	°C
Lead Lag CH 20 mA water temperature	561	U16	0.1	°C
Lead Lag CH Modbus setpoint	562	U16	0.1	°C
Lead Lag CH Modbus STAT	563	U16	1
Slave mode	564	U16	1
Slave command	565	U16	1
Base load rate	566	U16	1
Fan during off cycle rate	567	U16	1
Slave sequence order	568	U16	1
Lead Lag Modbus port	569	U16	1
Slave demand to firing delay	570	U16	1	s
Slave capacity	571	U16	1	MBH
Base load common rate	572	U16	0.1	%
Rate allocation method	573	U16	1
Lead allocation method	574	U16	1
Lag allocation method	575	U16	1
CH Modbus STAT	577	U16	1
CH setpoint source	578	U16	1
CH Modbus setpoint	579	U16	0.1	°C
CH modulation rate source	580	U16	1
CH Modbus rate	581	U16	1
CH priority vs. Lead Lag	582	U16	1
CH 4mA water temperature	583	U16	0.1	°C
CH 20mA water temperature	584	U16	0.1	°C
CH 4mA steam pressure	585	U16	0.1	psi
CH 20mA steam pressure	586	U16	0.1	psi
CH MODBUS STEAM SETPOINT	587	U16	1
CH HOT STANDBY ENABLE	588	U16	1
Heat exchanger high limit enable	592	U16	1
Heat exchanger high limit setpoint	593	U16	0.1	°C
Heat exchanger high limit response	594	U16	1
Heat exchanger high limit delay	595	U16	1	s
Heat exchanger retry limit	596	U16	1
PREFERRED OUTLET HIGH LIMIT	597	U16	1
PREFERRED STACK LIMIT SETPOINT	598	U16	1
FLAME FAILURE RESPONSE TIME	599	U16	1	s
DBI External Igniter On Time	600	U16	1	s
Flow Switch Enable	601	U16	1
Flow Switch Debounce Time	602	U16	0.1	s
Damper Proving Enable	603	U16	1
Damper Proving Debounce Time	604	U16	1	s
S1 (J8-4) connector type	608	U16	1
S2 (J8-6) connector type	609	U16	1
S3S4 (J8-8, 10) connector type	610	U16	1
S5 (J8-11) connector type	611	U16	1
S6S7 (J9-1, 3) connector type	612	U16	1
S8S9 (J9-4, 6) connector type	613	U16	1
S10 (J10-7) connector type	614	U16	1
Outdoor temperature correction offset	615	U16	1
Pressure correction offset	616	U16	1
Low fire cutoff time	617	U16	1
DOE Energy Saving	618	U16	1
Modbus Heartbeat	619	U16	1
Modbus Heartbeat Timeout	620	U16	1	s
Modbus Lockout	621	U16	1
Modbus Blower/HSI Output	622	U16	1
Modbus Blower/HIS Output Control	623	U16	1
Installer passcode	624	U16	1
OEM passcode	625	U16	1
Outdoor temperature source	626	U16	1
Warm weather shutdown enable	627	U16	1
Warm weather shutdown setpoint	628	U16	0.1	°C
Use STAT with EnviraCOM remote stat	629	U16	1
Line frequency	630	U16	1
Safety configuration options	631	U16	1
Controller interaction enable	632	U16	1
Blocked condensate enable	633	U16	1
Flap valve controller ID	634	U16	1
Number of controllers in flap valve system	635	U16	1
Maximum firing rate when neighbor starts up	636	U16	1
Stack fault from neighbor enable	637	U16	1
SOFT LOCKOUT ENABLE	638	U16	1
BURNER OFF INHIBIT TIME	639	U16	1
Modbus Analog Output	668	U16	0.1	%
Modbus Analog Output Control	669	U16	1
IAS Open Modulation Step Down	670	U16	1
IAS Open Modulation Step Down Time	671	U16	1	s
Plate preheat delay after tap	688	U16	1	s
Plate preheat setpoint	689	U16	0.1	°C
Plate preheat on recognition time	690	U16	1	s
Plate preheat on hysteresis	691	U16	0.1	°C
Plate preheat off hysteresis	692	U16	0.1	°C
Plate preheat minimum on time	693	U16	1	s
Tap detect degrees	694	U16	0.1	°C/s
Tap detect on hysteresis	695	U16	0.1	°C
Tap detect on recognition time	696	U16	1	s
Tap stop DHW-Inlet degrees	697	U16	0.1	°C
Tap stop Outlet-Inlet degrees	698	U16	0.1	°C
Tap minimum on time	699	U16	1	s
Tap detect on threshold	700	U16	0.1	°C
Preheat detect on threshold	701	U16	0.1	°C
Preheat detect off threshold	702	U16	0.1	°C
Lead Lag DHW demand switch	704	U16	1
Lead Lag DHW setpoint	705	U16	0.1	°C
Lead Lag DHW priority vs. CH	706	U16	1
Slave dropout/return compensation	713	U16	1
Add stage method	714	U16	1
Add stage detection time	716	U16	1	s
Add stage error threshold	718	U16	0.1	°C
Add stage rate offset	719	U16	0.1	%
Add stage error gain	720	U16	1
Add stage rate gain	721	U16	1
Add stage inter-stage delay	722	U16	1	s
Drop stage method	723	U16	1
Drop stage detection time	725	U16	1	s
Drop stage error threshold	727	U16	0.1	°C
Drop stage rate offset	728	U16	0.1	%
Drop stage error gain	729	U16	1
Drop stage rate gain	730	U16	1
Drop stage inter-stage delay	731	U16	1	s
Lead rotation time	733	U16	1	min
Force lead rotation time	734	U16	1	min
Lead Lag DHW time of day setpoint	735	U16	0.1	°C
Boiler off options	736	U16	1
All boilers off threshold	737	U16	0.1	°C
Lead Lag pressure setpoint	738	U16	0.1	psi
Lead Lag pressure TOD setpoint	739	U16	0.1	psi
Lead Lag pressure on hysteresis	740	U16	0.1	psi
Lead Lag pressure off hysteresis	741	U16	0.1	psi
Add stage pressure error threshold	742	U16	0.1	psi
Drop stage pressure error threshold	743	U16	0.1	psi
Lead Lag minimum pressure	744	U16	0.1	psi
Lead Lag 4 mA steam pressure	745	U16	0.1	psi
Lead Lag 20 mA steam pressure	746	U16	0.1	psi
Lead Lag Modbus pressure setpoint	747	U16	0.1	psi
Lead Lag manual slave request	748	U16	1
Lead Lag manual slave rate	749	U16	1
Auxiliary 1 pump overrun time	752	U16	1	s
Auxiliary 1 pump options 1	753	U16	1
Auxiliary 1 pump options 2	754	U16	1
Auxiliary 2 pump output	755	U16	1
Auxiliary 2 pump control	756	U16	1
Auxiliary 2 pump start delay	757	U16	1	s
Auxiliary 2 pump overrun time	758	U16	1	s
Auxiliary 2 pump options 1	759	U16	1
Auxiliary 2 pump options 2	760	U16	1
Lead Lag active service	768	U16	1
Slave 1 address	769	U16	1
Slave 1 state	770	U16	1
Slave 1 stage order	771	U16	1
Slave 1 firing rate	772	U16	1
Slave 2 address	773	U16	1
Slave 2 state	774	U16	1
Slave 2 stage order	775	U16	1
Slave 2 firing rate	776	U16	1
Slave 3 address	777	U16	1
Slave 3 state	778	U16	1
Slave 3 stage order	779	U16	1
Slave 3 firing rate	780	U16	1
Slave 4 address	781	U16	1
Slave 4 state	782	U16	1
Slave 4 stage order	783	U16	1
Slave 4 firing rate	784	U16	1
Slave 5 address	785	U16	1
Slave 5 state	786	U16	1
Slave 5 stage order	787	U16	1
Slave 5 firing rate	788	U16	1
Slave 6 address	789	U16	1
Slave 6 state	790	U16	1
Slave 6 stage order	791	U16	1
Slave 6 firing rate	792	U16	1
Slave 7 address	793	U16	1
Slave 7 state	794	U16	1
Slave 7 stage order	795	U16	1
Slave 7 firing rate	796	U16	1
Slave 8 address	797	U16	1
Slave 8 state	798	U16	1
Slave 8 stage order	799	U16	1
Slave 8 firing rate	800	U16	1
Lead boiler address	801	U16	1
Master firing rate	802	U16	1
Active Lead Lag pressure setpoint	803	U16	0.1	psi
Active Lead Lag pressure on hysteresis	804	U16	0.1	psi
Active Lead Lag pressure off hysteresis	805	U16	0.1	psi
Active Lead Lag pressure operating point	806	U16	0.1	psi
Flap valve system state	816	U16	1
Lockout history record 1	864	U16	1
Lockout history record 2	880	U16	1
Lockout history record 3	898	U16	1
Lockout history record 4	915	U16	1
Lockout history record 5	932	U16	1
Lockout history record 6	949	U16	1
Lockout history record 7	966	U16	1
Lockout history record 8	983	U16	1
Lockout history record 9	1000	U16	1
Lockout history record 10	1017	U16	1
Lockout history record 11	1034	U16	1
Lockout history record 12	1051	U16	1
Lockout history record 13	1068	U16	1
Lockout history record 14	1085	U16	1
Lockout history record 15	1102	U16	1
Alarm code	1119	U16	1
Alert log record 1	1120	U16	1
Alert log record 2	1126	U16	1
Alert log record 3	1132	U16	1
Alert log record 4	1138	U16	1
Alert log record 5	1144	U16	1
Alert log record 6	1150	U16	1
Alert log record 7	1156	U16	1
Alert log record 8	1162	U16	1
Alert log record 9	1168	U16	1
Alert log record 10	1174	U16	1
Alert log record 11	1180	U16	1
Alert log record 12	1186	U16	1
Alert log record 13	1192	U16	1
Alert log record 14	1198	U16	1
Alert log record 15	1204	U16	1
Alert data 1	1210	U16	1
Alert data 2	1211	U16	1
Alert data 3	1212	U16	1
Alert data 4	1213	U16	1
Alert data 5	1214	U16	1
Alert data 6	1215	U16	1
Alert data 7	1216	U16	1
Alert data 8	1217	U16	1
Alert data 9	1218	U16	1
Alert data 10	1219	U16	1
Alert data 11	1220	U16	1
Alert data 12	1221	U16	1
Alert data 13	1222	U16	1
Alert data 14	1223	U16	1
Alert data 15	1224	U16	1

link settings as documented (unverified): RTU; default 38400 8N1; FC 03,06,16,17; RS-485 half duplex, LSB first, idle line for 3.5 or more characters.

bench facts as documented (unverified)

terminals	3-pin connector
A/B polarity	Terminal 1: Data + (a), Terminal 2: Data - (b), Terminal 3: Common (c)
connector	3-pin connector
wiring notes	MB1 or MB2 Modbus ports
max registers/read	125
sentinel values	0x8FFF for unconfigured temperature parameters, 0x7FFF or 0x8200 for no sensor configured, 0x8000 for shorted, 0x8100 for open, 0x8300 for outside high range, 0x8400 for outside low range, 0x8500 for not reliable.
protocol notes	Except for variable length data items, registers can be accessed as a single register or up to 20 registers for writes and 125 registers for reads. Variable length data must be accessed individually.
model register	176
firmware register	186
identification notes	Report Slave ID (FC17) returns OS number and Burner name. OS number is also at register 186, Burner name is at 183.
FC 43 device ID	not supported
doc revision	4.1.1

field reports — community-sourced, unverified (checked 2026-06-11)

Writing to any data register requires a password login (e.g., 'sola') to be written to register 177 (0x00B1) first, which remains in effect for only 10 minutes before another login is required. [source]
After a Modbus communication failure, the 'Comm Failure' alarm is not cleared until a successful write to both the Remote On/Off Modbus Command (00004) and Remote Firing Rate or Remote Setpoint (40006) points have been completed, or power is cycled. [source]
confirmed: Baud rate default of 38400, RTU framing, and half-duplex RS-485 comms — confirmed by Honeywell SOLA Software Interface Specification and Resideo R7910B User Manual
confirmed: Report Slave ID (FC17) returns OS number and Burner name — confirmed by Resideo R7910B User Manual
confirmed: OS number is at register 186 and Burner name is at register 183 — confirmed by CleaverBrooks CFC Operation Manual and CBT Tubeless Steam Boiler Manual
confirmed: Polarity of MB1/MB2 Modbus ports (Terminal 1/a: Data +, Terminal 2/b: Data -, Terminal 3/c: Common) — confirmed by CBT Tubeless Steam Boiler Manual
confirmed: Max read registers of 125 and write limit of 20 — confirmed by Honeywell SOLA Software Interface Specification
confirmed: Sentinel values (0x8FFF for unconfigured, 0x7FFF/0x8200 for no sensor, 0x8000 for shorted, 0x8100 for open, 0x8300/0x8400 for out of range, 0x8500 for unreliable) — confirmed by Honeywell SOLA Software Interface Specification

The trust ladder

Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.

generated — A prompt produced it. Unproven — anyone can regenerate this.
structure-verified — Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.
coherence-checked — Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.
hardware-verified (software-key) x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.

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