Download Honeywell 7800 Hard Reset File

The 7800 Series is microprocessor-based control, factory programmed for burner sequencing, flame supervision, system status indication, and stores an immense amount of information in its memory, all of which is retrievable by using the S7800 display module. The S7800 display module can retrieve the complete burner controller data: sequence status, sequence time, hold status, lockout alarm status, flame signal strength, total hours of operation, total cycles of operation, and if an expanded annunciator is connected, its status. The display can be scrolled through the history of the six most recent faults showing cycles of operation at time of fault, fault message and code, hours of operation at the time of fault, sequence status at time of fault, sequence time at time of fault, and if an expanded annunciator is connected, its data at time of fault. Diagnostic information includes the device type, flame amplifier type, flame failure response time, manufacturer code, on/off status of all inputs and outputs, pre-purge time selected, software revisions, status of configuration jumpers, and the status of the run test switch.

All the series 7800 devices use the same sub-base, the Q7800. The Q7800A is two-sided for use in burner panels. The Q7800B is four-sided for wall or burner mounting. While usually mounted vertically, the 7800 controls can be mounted in any position except horizontally pointing down. Only two screws hold the relays to the sub-base. The 22 terminals on the sub-base are of the knife blade style, making the installation of the relays to the sub-base quick and easy. For wiring the sub-base, each terminal number is cast into the plastic holding the terminal. There is also a thin plastic sheet at the bottom of the base with terminal numbers on it. Each terminal can hold up to two #14 size wires.

UVM and TFM 2, 3, 5 = RM7895’s

D Series = RM7840’s

Q. Just what are the differences between the RM7800/7840E, L, G, and M?

Q. What happens if the air flow switch contacts weld or stick closed? (Same as jumping the air flow switch.)

Now look at Figure 3. On the E and L, all terminal functions are the same. Note that the only difference between an RM7800E and RM7800L is how the H.F.P.S. is wired to terminal 19. On the E, it is between terminals 4 and 19, resulting in “energy saving purge.” On the L, the H.F.P.S. is between terminals 5 and 19.

A. No. Unlike the R4140’s, the RM7800’s will wait for 4 minutes and 15 seconds for the switch to close, and then lock out. The same thing happens if the low fire start switch fails to close on all RM7800/7840.

Ambient Temperature Range: -40 F to +140 F (-40 C to +60 C)

RM7840 – Microprocessor-based integrated burner control for automatically fired gas, oil, coal or combination fuel single burner applications. Provides safety, functional capability and features beyond conventional controls.