Troubleshooting - Temp-O-Matic TMP Multi-Position User Manual

9

Troubleshooting

Before beginning these troubleshooting procedures, ALWAYS :
Check 120 volt supply to furnace. If there is no supply
voltage, check fuses and service switch. CAUTION :
When testing electrical equipment, always follow
standard electrical safety procedures.
Make sure thermostat is calling for burner operation.
Check oil supply and make sure all valves are open.
Sym ptom – Burner
Burner m otor does not sta rt.
Burner s hort c ycles or locks out on
prim ary re lay safety.
Unable to a chieve clean combustion
by se tting air adjustme nts .
To check CAD cell operation, use t he
following proce dure :
Symptom – Furnace blower
Furnace blower will not start.
Blower cycles on and off after the
burner has shut down.
Blower short cycles on limit control.
670-000-004/1010
To successfully service the oil furnace, you must
have these instruments :
smoke tester
carbon-dioxide (CO
draft gauge (scale should read from -.01" w.c. to -.25" w.c.)
volt/OHM/milliamper multimeter
pressure gauge capable of reading 0-150 lb/sq. inch (for oil only)
Be familiar with these instruments as well as the burner
manufacturers recommended settings.
Possible correct ions :
Check fuses and make sure service switch
is o n.
Check for li ne volta ge into furnace jun ction
box.
If the prima ry relay control is not po pping
out th e reset b utton,
milliamp erage at th e thermostat and se t the
heat-an ticipator a ccord ingly. A lso check
wiring fr om the thermostat to the bu rner.
Ch eck nozzle a nd electr ode position.
(Reference burner man ufa cturers
instructio ns) .
Check tube insertion and ali gnment.
Replace nozzl e.
Check overfire draft.
1. Remove CA D cell leadwires from the f-f
terminals on the p rimary safety con tro l, then
sta rt burner. S hortly after burner starts,
place a temporar y
terminals f-f. Co nnect oh mete r a cro ss CA D
cell lead wires-re sistance should b e under
1,600 ohms.
2. Stop burne r a nd remove tempor ary jumpe r.
Possible corrections :
Check for 120V to the blower motor. If
present, replace motor.
Check wiring from Fan and Limit control. See
if blower motor will run when it is switched on
manually at the thermostat sub-base (if sub-
base is installed).
Adjust fan "off" setting at 90
o
"on" setting setting at 130 .
Return ducts may be undersized.
TMP
Oil Furnaces
) or oxygen (O
2 2
Check for vol tag e from primary re lay to
bu rner motor. Make sure th e prima ry relay
ha s not locke d o ut on safety.
Make sure the thermostat is calling for heat and
that the wiring to the thermostat is correct and tight.
Check the alig nment of th e cad cell to
measure the assure it is aimed at the fire.
Check ig nition tra nsforme r ou tpu t
Check n ozzle and electrode position
(Reference burn er ma nufacture rs
instructions).
Check
manu facturer and ap plicati on; se e burne r
manu al).
3. Wi th burner off, check dark cel l resista nce
across
shoul d b e gr eater than 20 ,00 0 o hms. If cel l
jumpe r b etween resistances
reche ck wi ring and lo ca tion of cell , etc. If
ne cessary, rep lace p lug-in portion of ce ll.
o
and adjust fan
– Furnace Manual
) analyzer
pump pressure (va ries
CA D cell leadwires. Resista nce
a re differe nt from
with
above,
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