Common questions about Honeywell 7800 Series burner controls, flame amplifiers, fan coil thermostats, Modutrol motors, and actuator selection. Contact us or call (901) 458-2000 — Memphis Control Center has been an authorized Honeywell distributor since 1967.
What does a complete Honeywell 7800 Series burner control system require?
A complete 7800 Series system requires four components: (1) Relay module — RM7800L, RM7840, RM7890, or other 7800 variant (RM7800L1012 is the most common 120 VAC model). (2) Q7800 wiring subbase — Q7800A1005 (panel mount) or Q7800B1003 (burner/wall mount). (3) Flame amplifier — R7847 for flame rod, R7849 for UV scanners (C7027/C7035), R7851 for C7927 UV scanners. Amplifier type must exactly match your flame detection method. (4) Flame scanner — C7027 Mini-Peeper (UV), C7927 (UV solid state), or C7012 (UV, Purple Peeper). Optional: S7800A1142 keyboard display for full diagnostics and valve proving. Call (901) 458-2000 with your existing system configuration — we will identify the correct replacement components.
What is the difference between R7847, R7849, and R7851 flame amplifiers?
These are all 7800 Series plug-in flame amplifiers, but each is designed for a specific detection method: R7847 — flame rod (ionization rod) detection. R7847A is standard; R7847B adds AmpliCheck® self-check circuitry. R7849 — UV scanner (C7027 Mini-Peeper, C7035). R7849A is standard; R7849B adds AmpliCheck®. R7851 — C7927 UV solid state scanner. R7851B adds AmpliCheck®; R7851C adds dynamic self-check. The suffix letters within each family indicate the Flame Failure Response Time (FFRT) — A or B versions ending in "25" or "23" are 0.8-second FFRT; "33" or "31" are 3.0-second FFRT. The amplifier must match your scanner type — installing the wrong amplifier results in lockout or unsafe operation. Call (901) 458-2000 to confirm the correct amplifier.
What does the TB6575A1000 replace?
The Honeywell TB6575A1000 SuitePRO fan coil thermostat is a direct replacement for: TB6575A1016, T6051A1016, T6575D1009, T6069A4010, T6575B1003, and T6575C1001 — as noted in Honeywell product documentation and confirmed on the Memphis Control Center product listing. It provides equivalent 2-pipe/4-pipe fan coil unit functionality with 3-speed fan control and 50–90°F setpoint range. If you're replacing a model not in this list, call (901) 458-2000 with the existing model number before ordering.
What is the difference between Modutrol IV motors and direct-coupled damper actuators?
Modutrol IV motors (M4185, M6184, M7185, M9184 series) are foot-mounted rotary actuators that connect to damper or valve shafts via mechanical linkage — crank arms, push-pull rods, and brackets. They are the traditional Honeywell actuator for large commercial air handling units, VAV systems, and industrial valve applications. Direct-coupled damper actuators (MS Series and MN Series) clamp directly to the damper shaft without linkage, making them faster to install and more compact. MS Series are two-position (fully open/closed); MN Series are modulating (0–10V or 2–10V DC signal). Choose Modutrol when replacing an existing Modutrol system or when high torque is needed. Choose direct-coupled for new installations or where compact installation is preferred. Call (901) 458-2000 for a recommendation.
Can Memphis Control Center source Honeywell parts not listed on the website?
Yes. As an authorized Honeywell Gold PMT Channel Partner, we have direct access to the full Honeywell Thermal Solutions product catalog — including products not currently listed on our website. If you need any Honeywell part number — 7800 Series relay modules, Modutrol motors, gas valves, amplifiers, sensors, thermostats, process controllers, or any other Honeywell Thermal Solutions product — call (901) 458-2000 or use the contact form with the full part number. We will confirm availability and lead time. Memphis Control Center has been an authorized Honeywell distributor since 1967.
What is the difference between RM7800, RM7840, RM7895, RM7897, and RM7838?
All are 7800 Series relay modules using the same Q7800 subbase, but each serves a different burner type or application: RM7800 — programmer for on/off and full modulation single-burner applications (gas, oil, combination fuel). The RM7800L1012 is the most common 120 VAC model; RM7800L1087 adds Valve Proving System (VPS). RM7840 — modulating burner programmer for full-modulation fired equipment where firing rate varies continuously rather than on/off. RM7840L1018 is the standard modulating model; RM7840L1075 adds VPS. RM7895 — on/off primary control with prepurge, FM/IRI approved for applications where FM or industrial risk underwriters require higher approval levels. RM7897 — on/off with pre- and programmable post-purge plus VPS; required where valve proving is mandated. RM7838 — industrial manual-start programmer for semi-automatically fired industrial burners where an operator initiates each start sequence. If you're unsure which chassis your application requires, call (901) 458-2000 — our team has been specifying Honeywell flame safeguard controls since 1967.
The C7012 Purple Peeper is obsolete — what replaces it, and what else changes?
The Honeywell C7012 Purple Peeper UV detector is discontinued and no longer manufactured. The supported replacement is the C7061 dynamic self-check UV flame detector. This is not a plug-in swap — two things must change together: (1) Scanner: C7012 → C7061. (2) Flame amplifier: the R7847 R7847 amplifier used with the C7012 UV detector must be replaced with an R7861 dynamic self-check amplifier compatible with the C7061. If you replace only the scanner without changing the amplifier, the system will not operate correctly. The R7861 fits the same Q7800 amplifier socket as the R7847, so no subbase or relay module wiring changes are required — only the amplifier module and the scanner are swapped. Call (901) 458-2000 — we stock both the C7061 and R7861 and can confirm your system configuration before you order.
What is the difference between C6097A and C6097B pressure switches?
The suffix letter tells you the action: C6097A breaks (opens its circuit) on a pressure fall — used wherever you need the burner to shut down when pressure drops below a setpoint. Typical applications: low-gas-pressure cutoff (gas proving switch to confirm supply pressure before ignition), low-air-pressure proving on forced-draft systems, and low-limit safety on LP gas systems. C6097B breaks on a pressure rise — used wherever you need the burner to shut down when pressure exceeds a setpoint. Typical applications: high-gas-pressure safety shutoff, high-air-pressure cutoff, and overpressure protection. Within each family, further digits indicate the pressure range and reset type: auto-reset (automatically restores when pressure returns to normal) vs manual-reset (must be physically reset at the switch after a trip — required by some codes for safety-critical circuits). Memphis Control Center stocks both C6097A and C6097B variants across pressure ranges from 0.4" W.C. to 200" W.C. Browse all C6097 switches or call (901) 458-2000 for range selection help.
