background image

RM7895A RELAY MODULE

5

32-00122-01

Fig. 3. Ultraviolet detectors.

PRINCIPAL TECHNICAL 
FEATURES

The RM7895 provides all customary flame safeguard 
functions while providing significant advancements in the 
areas of safety, annunciation and system diagnostics.

Safety Shutdown (Lockout) Occurs 
If:

1.

INITIATE PERIOD
a. Purge card is not installed or is removed.
b. Purge card is bad.
c. Configuration jumpers have been changed after 

200 hours of operation.

d. Ac line power errors occurred, see Operation.
e. Four minute INITIATE period has been exceeded.

2.

STANDBY PERIOD
a. Flame signal is present after 40 seconds.
b. Ignition/pilot valve/intermittent pilot valve ter-

minal is energized.

c. Main valve terminal is energized.
d. Internal system fault occurred.
e. Purge card is not installed or is removed.
f.

Purge card is bad.

3.

PREPURGE PERIOD
a. Airflow lockout feature is enabled and the airflow 

switch does not close after ten seconds or within 
the specified purge card timing.

b. Flame signal is detected after 30 seconds.
c. Ignition/pilot valve/intermittent pilot valve ter-

minal is energized.

d. Main valve terminal is energized.
e. Internal system fault occurred.
f.

Purge card is removed.\

g. Purge card is bad.

4.

PILOT FLAME ESTABLISHING PERIOD (PFEP)
a. Airflow lockout feature is enabled and the airflow 

switch opens.

b. Ignition/pilot valve terminal is not energized.
c. No flame present at end of PFEP.
d. Main valve terminal is energized.
e. Internal system fault occurred.
f.

Purge card is removed.

g. Purge card is bad.

5.

RUN PERIOD
a. No flame present.
b. Airflow lockout feature is enabled and the airflow 

switch opens.

c. Main valve terminal is not energized.
d. Internal system fault occurred.
e. Purge card is remove.
f.

Purge card is bad.

SAFETY PROVISIONS

Internal Hardware Status 
Monitoring

The RM7895 checks the purge card for correct parity to 
prevent purge timing shifts and circuitry failures. It also 
analyzes the integrity of the configuration jumpers and 
internal hardware. The POWER LED will blink every four 
seconds, signifying an internal hardware check.

COLLAR WITH 1/2-14 NPSM 

INTERNAL THREADS

4 (102)

8 FOOT (2.44 METER)

LEADWIRES (2)

M1943F

C7027A1064 HAS 24 FOOT (7.32 METER) LEADWIRES.

C7027A1114 HAS 44 IN. (1.118 M) LEADWIRES WITH 

22 IN. (558 MM) FLEXIBLE CONDUIT.

1

2

2

3-1/2 (89)

1-1/16

(27)

1

MODELS AVAILABLE WITH SPUD CONNECTOR (1/2-14 NPSM INTERNAL

THREADS) INSTEAD OF CLAMP TYPE CONNECTOR.

1/2-14 NPSM

INTERNAL THREADS

2

2 (51)

COLLAR WITH

1 - 1-1/2 NPSM

INTERNAL

THREADS

1

1

DIN APPROVED C7035A1064 HAS 1-11 BSP.P1 INTERNAL MOUNTING THREADS.

DIN APPROVED C7035A1064 HAS 1/2-14 BSP-F INTERNAL MOUNTING THREADS.

C7035A1056 HAS 12 FOOT (3.66 METER) LEADWIRES.

2

3

INSERTION DEPTH

6 FOOT 

[1.83 METER]

LEADWIRES (2)

3

M1945D

2-5/8 (67)

1-1/2

(38)

31/32

(25)

4-1/8 (105)

1-3/16

(30)

 

6 FOOT [1.83 METER]

LEADWIRES (2)

MOUNTING BRACKET

3-5/8 (92)

1/2

(13)

1-27/64

(36)

3/8

(10)

7/8

(22)

9/16

(14)

M1944B

Summary of Contents for RM7895A

Page 1: ...c input check Dynamic safety relay test Dynamic self check logic Internal hardware status monitoring Tamper resistant timing and logic Access for external electrical voltage checks Application Flexibi...

Page 2: ...ing the current to blow the 15A fuse or breaker in event of an internal short circuit The RM7895 needs a low impedance ground connection to the equipment frame which in turn needs a low impedance conn...

Page 3: ...in Flame Signal Amplifier see Table 2 Plug in Purge Timer Cards selectable ST7800A two sec onds to 30 minutes Q7800A Wiring Subbase Accessories 203541 5 wire connector required when Keyboard Dis play...

Page 4: ...5 127 M3529 5 1 4 133 REMOVE ONLY FOR TERMINAL TEST ACCESS 1 1 BURNER CONTROL R MOUNTING FLANGE 1 2 14 NPSM LEADWIRES FACEPLATE 3 4 14 NPT M1962B 3 3 4 95 7 7 32 183 5 1 8 130 3 7 16 87 5 1 4 133 C701...

Page 5: ...terminal is not energized c No flame present at end of PFEP d Main valve terminal is energized e Internal system fault occurred f Purge card is removed g Purge card is bad 5 RUN PERIOD a No flame pres...

Page 6: ...and self checking detector are energized for the first 40 seconds during STANDBY and the last two seconds before exiting STANDBY If a flame exists a safety shutdown occurs A standard amplifier is ener...

Page 7: ...trol and the main fuel valve s 2 Two flame detectors can be connected in parallel 3 This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance wit...

Page 8: ...All wiring must comply with applicable electrical codes ordinances and regulations Wiring where required must comply with NEC Class 1 Line Volt age wiring 4 Recommended wire size and type see Table 4...

Page 9: ...quired for the RM7895 Add the required disconnect means and overload protection 2 Check all wiring circuits and complete the Static Checkout see Table 7 before installing the RM7895 on the subbase 3 I...

Page 10: ...lifier flame amplifier signal probes electrical signal voltage probes and electrical connections M3536B G L2 3 4 5 6 7 8 9 10 F L1 13 14 15 16 17 18 19 20 21 22 12 AIR FLOW INTERLOCK MASTER SWITCH IGN...

Page 11: ...Fig 8 2 Insert the two interlocking ears into the two mating slots and with a hinge action push on the upper corners of the Dust Cover to secure it to the RM7895 3 Be sure the Dust Cover is firmly in...

Page 12: ...ut Causes for hold conditions in the INITIATE sequence are AC line dropout is detected AC line frequency error caused by using a 60 Hz device on a 50 Hz line or vice versa devices with a date code pri...

Page 13: ...If 10 second PFEP is chosen main valve terminal 9 is turned on as soon as flame is sensed Ignition terminal 10 is de energized as soon as the main valve is energized The pilot valve remains energized...

Page 14: ...red correctly and that the external controllers limits interlocks actuators valves transformers motors and other devices are operating properly IMPORTANT Do not perform a dielectric test with the RM78...

Page 15: ...oltage at terminal 6 1 Limits 2 Burner controller 3 4 5 7 L2 1 Burner motor fan or blower starts 2 Line voltage at terminal 7 within 10 seconds 1 Burner motor circuit a Manual switch of burner motor b...

Page 16: ...the flame detector s in the FINAL position Equipment Recommended Volt ohmmeter 1 Mohm volt minimum sensitivity with 0 300 Vac capability 0 6000 ohm capability 0 10 Vdc capability Checkout Summary Pre...

Page 17: ...e rod make sure Ground area is large enough Flame rod is properly located in the flame Temperature at the flame rod insulator is no greater than 500 F 260 C 4 For all optical detectors clean the detec...

Page 18: ...16 10 If the main burner flame is not established within five seconds or the normal lightoff time specified by the equipment manufacturer close the manual main fuel shutoff valve s 11 Recycle the sys...

Page 19: ...ents for flame stability and input rating e Shut down the system by lowering the set point of the operating controller Make sure the burner flame goes out and all automatic fuel valves close Proceed t...

Page 20: ...cessary to construct a barrier to block the ignition spark from the detector view Continue adjustments until the flame signal due to ignition spark is less than 0 5 Vdc NOTE The Honeywell Q624A Solid...

Page 21: ...Troubleshooting manual form 65 0233 The RM7895 provides diagnostic information to aid the service mechanic to obtain information when troubleshooting the system see Table 8 The optional Keyboard Disp...

Page 22: ...STANDBY until the line voltage is at a sufficient level for proper operating parameters STANDBY The LED indicates the burner status POWER The burner can be placed in STANDBY by opening the burner swi...

Page 23: ...es shall be connected to the Burner Controller DDL line License agreement Copying and reverse engineering is prohibited by the law PURGE HOLD Airflow Interlock The LED indicates the burner status POWE...

Page 24: ...RM7895A RELAY MODULE U S Registered Trademark 2018 Honeywell International Inc 32 00122 01 M S Rev 08 18 Printed in United States...

Reviews: