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Honeywell R4795A Manual Download Page 12

60-2285—7

12

R4795A

TROUBLESHOOTING

F. Pilot lights and relay 2K pulls in but the main burner

does not light.

G. Relay 2K remains in after flame is extinguished.
H. Miscellaneous problems:

1. Repeated lockouts or control failures.
2. Ignition interference (flame rod installations only).

TROUBLESHOOTING PROCEDURES

CAUTION

1. Use extreme care while troubleshooting the

R4795; line voltage is present on most contacts
when power is On.

2. Open the master switch before removing the

cover, cleaning contacts, removing R4795 from
subbase, or reinstalling R4795 on subbase. See
Fig. 9 for relay location.

IMPORTANT:

1. Clean contacts only when instructed to do so in a

troubleshooting procedure. Follow the instructions in
Contact Cleaning section.

2. If, after completing an applicable Troubleshooting

Procedure, proper operation still cannot be obtained,
replace the R4795 (except amplifier and purge timer,
unless noted).

A. Relay 3K does not pull in on a call for heat

1. Check for power at terminals 1 and 2 with the control-

ler calling for heat.
a. Voltage must be within plus 10 to minus 15 percent

of the rated voltage for dependable operation.

b. If voltage is zero, check the continuity of the limit

and controller contacts and check the power sup-
ply. Look for blown fuses, open switches, and bad
wiring connections.

2. If voltage at terminals 1 and 2 is satisfactory and relay

3K will not pull in, clean the 1K and 3K relay contacts.
Press safety switch button several times to clean the
contacts. If trouble persists, replace the R4795.

B. Relay 3K pulls in but the burner motor does not start

1. Check for power at terminal 8 when the 3K relay

pulls in.
a. If terminal 8 is not powered, clean the 3K relay

contacts and recheck for power. If terminal 8 can-
not be powered, replace the R4795.

b. If terminal 8 is powered, check the fan or burner

motor.

C. Burner motor starts but prepurge does not stop at end

of purge timing (relay 1K does not pull in)
1. Check the seating of the plug-in purge timer.
2. Check that the airflow switch contacts are making.

Approximately 20 Vdc should appear between termi-
nals 7 (plus) and G (minus) when airflow switch con-
tacts are made.

3. Check the position of the flame relay. If relay 2K is

pulled in, check for flame simulating condition.

4. If the flame relay is not pulled in, clean the 2K relay

contacts.

5. Replace the purge timer with one of the same timing.

If problem still continues, replace the R4795.

D. Relay 1K pulls in but the pilot does not light, ignition

does not occur, or expanding pilot valve does not open
1. Make sure that all manual fuel valves are open.
2. Check voltage between terminals 3 and 2, or 4 and 2,

as applicable. (Terminal 3 is used for pilot or first stage
oil valve; terminal 4 for ignition.) Check must be made
before control locks out on safety.

3. If zero voltage, clean the 1K and 2K relay contacts;

then recycle the system and recheck the voltage at ter-
minal 3 or 4. If terminals cannot be powered, replace the
R4795.

4. If correct voltage at terminals 3 and 4, check the pilot

valve and ignition and the circuits.

E. Pilot lights but relay 2K does not pull in (control locks

out without lighting the main burner)
1. Use a 121708 Rectification or a 203659 or 123514B

Ultraviolet Flame Simulator to check the flame relay.
Follow the instructions for the simulator.

2. If no flame simulator is available, do a flame current

check. If the flame current is satisfactory, replace the
R4795. If the flame current is not satisfactory, recheck
all items.

F. Pilot lights and relay 2K pulls in but the main burner

does not light
1. Check that the manual main fuel valves are all open.
2. Check the voltage at terminal 5 when the 2K relay

pulls in.
a. If normal voltage at terminal 5, check the main

valve and the external valve circuit.

b. If zero voltage at terminal 5, clean the 2K relay

contacts. If terminal 4 cannot be powered, replace
the R4795.

G. Relay 2K remains in after flame is extinguished

1. If the flame detector is a rectifying flame rod, install a

new plug-in amplifier.

2. If the flame detector is a rectifying photocell or C7012

Ultraviolet Detector, plug the back end of the flame
simulator into the jack of the plug-in amplifier.
a. If that does not cause relay 2K to drop out, install a

new plug-in amplifier.

b. If plugging into the meter jack causes relay 2K to

drop out, the trouble is caused by hot refractory
hold-in, detector failure, or other flame simulating
conditions.
(1) Resight the photocell at a cooler or more re-

mote area of the refractory.

(2) Recheck the flame detector current for the

condition recommended in the Checkout sec-
tion. Replace the detector if necessary.

Summary of Contents for R4795A

Page 1: ...repurge if the flame goes out while burner is running If pilot flame is not re established safetyswitchtripsandlocksoutsystem A tripped safety switch must be manually reset to restore operation Push to resetsafetyswitchisdust resistantenclosed Optional spdt alarm contacts operate external alarm on safety switch lockout Ignition interference circuit rectification amplifier only protects electronic ...

Page 2: ...t contacts Male quick connect terminals female quick connects included See Terminal Ratings 40 F 40 C models have isolated spdt alarm contacts Ordering Information When purchasing replacement and modernization products from your TRADELINE wholesaler or your distributor refer to the TRADELINE catalog or price sheets for complete ordering number or specify 1 Order number 3 Flame failure response tim...

Page 3: ...tion Design Certified File no 21 6 F and F1 ACCESSORIES W136A Test Meter includes 117053 Meter Connector Plug Flame Simulator 203659 Ultraviolet 121708 Rectification 123514B Ultraviolet 117053 Meter Connector Plug FSP1535 Tester for operational check Q624 Solid State Spark Generator 118702E Remote Reset Cover 120 Vac 60 Hz 202471C Reset Cover for R4795A ADDITIONAL CONTROLS Order all additional con...

Page 4: ...ng tubes can result in failure of the sensingtubetoproperlydiscriminatebetweenflame conditions For systems using R4795A with R7290 Amplifiers use C7027 C7035 and C7044 Flame Detectors only on burners that cycle On and Off at least once every 24 hours Appli ances with burners that remain on for 24 hours continuously or longer should use the C7012E Flame Detector with the R7247C Amplifier or the C70...

Page 5: ...TS BURNER MOTOR AIR FLOW SWITCH TO FLAME DETECTOR FLAME ROD OR UV DETECTOR FLAME AMPLIFIER 1K4 3K2 2K2 2K3 MAIN FUEL VALVE S IGNITION PILOT VALVE CONTROLLER LIMIT S R4795A 8 7 6 F G 5 4 3 1 2 2 3 Fig 3 Wiring hookup of oil system with interrupted ignition M8683 L1 HOT L2 1 1 2 3 4 5 POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED FOR INTERMITTENT IGNITION CONNECT IGNITION...

Page 6: ...R FLAME DETECTOR 6 8 7 6 T T F G 2 1 3 4 5 AIR FLOW SWITCH SODERLESS CONNECTION 120V 120V M8684 R4795C Replacement In most cases the R4795A can directly replace the R4795C For standing pilot applications where the pilot flame was detected during the off cycle install a relay as shown in Fig 5 Flame Detector Wiring See Fig 6 Alarm Contacts Models with alarm contacts have three male quick con nect t...

Page 7: ...wandremovethecover seeFig 8 Position the R4795 over the Q270 Subbase Start all ten mounting screws and tighten uniformly These screws com plete electrical circuits terminal 1 excepted and hold the R4795 to the subbase L1 HOT L2 1 1 2 2 IF A LINE VOLTAGE ALARM IS USED THE R4795 MUST BE MOUNTED IN A SUITABLE ENCLOSURE POWER SUPPLY MUST MATCH THE ELECTRICAL RATINGS OF THE ALARM PROVIDE DISCONNECT MEA...

Page 8: ... SAFETY SWITCH RESET BUTTON CAPTIVE MOUNTING SCREWS 10 2K 3K M8680 ST71A PLUG IN PURGE TIMER PURGE TIMER CONNECTORS PLUG IN AMPLIFIER OPTIONAL ALARM TERMINALS AMPLIFIER CONNECTORS TEST JACK ARC GAP IGNITION INTERFERENCE PROTECTION R7289 RECTIFICATION AMPLIFIER ONLY PRELIMINARY INSPECTION Make certain that 1 Wiringconnectionsarecorrectandallterminalscrews are tight Use a meter to check the continui...

Page 9: ...ge c As the control attempts to restart the pilot turn the pilot back up slowly just until relay 2K pulls back in You will have 15 seconds to complete this step before lockout occurs d Again turn the pilot down slightly but not enough so theflamerelaydropsout Iftherelaydropsout simply allow the control to complete the purge period and then turn the pilot back up to pull in the flame relay as in st...

Page 10: ...so spark is produced between the electrode and ground 3 Checktheflamerelay2K Therelayshouldnotpullin The flame signal current should not be more than one fourth microampere 4 If relay 2K does pull in resight the detector farther out from the spark or away from possible reflection It may be necessary to construct a barrier to block the ignition spark from the detector view Continue adjustments unti...

Page 11: ...e 1K relay will not pull in The result will be a continuous purge safe failure Hot Refractory Hold in Photocell Installations If hot refractory holds in the flame relay at the end of the running cycle startup is prevented until the hot refractory no longer holds in the flame relay Troubleshooting The first step in troubleshooting the R4795A is to deter mine the location of the system trouble Reset...

Page 12: ... is pulled in check for flame simulating condition 4 If the flame relay is not pulled in clean the 2K relay contacts 5 Replace the purge timer with one of the same timing If problem still continues replace the R4795 D Relay 1K pulls in but the pilot does not light ignition doesnotoccur orexpandingpilotvalvedoesnotopen 1 Make sure that all manual fuel valves are open 2 Check voltage between termina...

Page 13: ... Howeliminated tabulatedinorderofimportance 1 Provide adequate flame grounding area 2 Be sure the ignition electrode and the flame rod are on opposite sides of the grounding area 3 Check for the correct spacings on the ignition electrode Spacing should be 1 16 in 1 6 mm to 3 32 in 2 4 mm for 6 000V systems 1 8 in 3 2 mm to 3 16 in 4 8 mm for 10 000V systems 4 Eliminate any marginal spacings at oth...

Page 14: ...e reasons 1 Some had solvents that could deteriorate plastic parts and wire insulation 2 Some leave an oily residue that will collect dust and dirt The residue will also break down to form various carbonaceousproducts Eitherresultwillcauseearlycontact failure Do not use an abrasive sand paper stock file etc or a burnishing tool to clean contacts Its use can cause early contact failure for these re...

Page 15: ...15 60 2285 7 ...

Page 16: ... Control Home and Building Control Honeywell Inc Honeywell Limited Honeywell Limitée 1985 Douglas Drive North 740 Ellesmere Road Golden Valley MN 55422 Scarborough Ontario M1P 2V9 Printed in Mexico www honeywell com bbc ...

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