Honeywell 7800 Series EC/RM7830A/7850A Combustion Relay Module

Product positioning and model differentiation

The 7800 series is a Honeywell microprocessor based integrated combustion safety controller used for automatic ignition and safe shut-off of single burners.

Model control type applicable to burner

EC/RM7830A ON/OFF switch type ignition/shutdown two-stage type

EC/RM7850A Full Modulation Continuous Modulation High Fire/Low Fire Proportional Adjustment

Common functions:

Automatic combustion timing control

Flame signal monitoring

System status indication

Self diagnosis and fault locking

Multilingual display (English/Spanish/French/German/Italian/Japanese)

Security and Certification

Safety level: SIL 3

EU standards: EN298, EN60730, EMC, Low Voltage Directive

International certifications: FM, Lloyd’s, GASTEC

Protection type: Stop Category 0 Immediate power off

Electrical specifications

Project parameters

RM version 120 Vac (+10/-15%), 50/60Hz

EC version 220/240 Vac (+10/-15%), 50/60Hz

Maximum power consumption of 10W

The maximum total load is 2000 VA

Insurance 15A rapid melting SC type

Working temperature -40 ° C~+60 ° C

Humidity 85% RH non condensing

Hardware structure

Core Unit

Microprocessor controller

Safety relay (dual redundant)

Relay feedback monitoring

Pluggable component

Flame amplifier (R7847/7848/7849/7861/7886)

Purging time card (2s~30min)

Configure jumper wires

external extension

KDM keyboard display module

RS485/ModBus

remote reset

PC monitoring software

Terminal definition (core output)

1) EC/RM7830A key terminal

3: AL alarm

4: FAN fan

8: PV1 small fire valve

9: MV main fire valve

10: IGN ignition

17: ES2 pre ignition interlock

20: LOS lock input

21: PV2 auxiliary small fire

2) EC/RM7850A adds modulation terminal

12: Hi High Fire

13: COM Public

14: MOD modulation

15: LO low fire

18: ES1 low flame switch

19: ES3 high flame switch

Installation specifications

Installation location

Vertical installation priority

Anti vibration<0.5G

Moisture proof, not exposed to the outdoors

Mandatory wiring requirements

High voltage ignition wires must not be in the same tube as signal wires

Flame detector cable metal shielding

Strong electricity complies with NEC Class 1

cable specification

Strong current: 14-18 AWG

Signal/Communication: 22 AWG twisted pair shielded

Maximum line length

Remote reset: 1000ft (305m)

Communication bus: 4000ft (1219m)

Combustion operation timing (fully automatic)

Initialize Initialization: 2s power self-test

Standby STANDBY: Waiting for heating request

Pre blowing PREPURGE: Fan start, air blowing

Pre ignition: Igniter power supply for 3 seconds

First safe time SAFETY 1:3/5s to establish flame

Small Fire Stable PILOT TAB.: 5s

Main Trial: 3/5s

Run: Normal combustion

Post blow POSTPURGE: 2/15/30s

Jumper configuration (key safety parameters)

Jumper function complete (uncut), cut off

JR1 first safety time 5s 3s

JR2 main fire test time 5s 3s

JR3 air volume switch is missing

Important rule: Change jumper after 200 hours of operation → permanently lock (Code110).

Static testing (mandatory for installation)

A total of 10-14 power-off/power on tests were conducted to verify:

Power supply, interlocking, alarm

Fan, ignition, small fire, main fire

Modulation motor (7850A)

Air volume switch, high and low fire limit

The fuel manual valve must be closed during testing to prevent explosion.

LOCKOUT trigger condition

No flame, flame loss

Pre blowing without air volume

Ignition timeout, valve not functioning

Missing/faulty blowing card

Change the jumper after 200 hours

Internal malfunction, abnormal power supply

Incorrect output during standby mode

Key issues

Question 1: What is the core difference between EC7830A and RM7830A? What is the core difference between 7830A and 7850A?

answer:

EC and RM: voltage difference; RM=120VAC，EC=220/240VAC。

7830A and 7850A: Different control methods; 7830A=ON/OFF, 7850A=Continuous Proportional Modulation (HI/LO/MOD).

Question 2: Why can’t the jumper be cut after the device has been running for 200 hours? What will happen? How to recover?

answer:

To prevent unauthorized modification of key parameters such as safety time/air volume switch on site.

Changing the jumper will trigger Code110 to permanently lock and cannot be reset.

Cannot be restored, the controller must be replaced.

Question 3: What is the function of pre blowing during burner start-up? What should be done if the air volume switch is missing?

answer:

Pre blowing exhausts residual combustible gases from the furnace to prevent detonation.

When there is no wind switch: keep the JR3 jumper and short-circuit terminals 6-7.

When there is an air volume switch: cut off JR3 and strictly prohibit 6-7 short circuiting, otherwise it will be locked.