LAARS Mini-Therm JVi - Install and Operating Manual - Manual (Page 20)

Mini-Therm JVi Page 19
# Symptom Cause Remedy
1. Pump not operating No power . . . . . Check circuit breakers and power source.
Pump defective . . . . . Replace.
Incorrectly wired . . . . . Recheck wiring diagrams.
2. Pilot outage Inlet gas pressure too low . . . . . Consult gas utility company. Inlet gas pressure
to boiler should be 5.5" (1.4 kPa) to 9.0" (2.2 kPa)
water column on natural gas. 10.0" (2.5k Pa) to
14.0" (3.4 kPa) on propane gas.
Inlet gas pressure to high causing an
unstable blowing pilot . . . . .
Pressure should be regulated within limits
shown above.
Damaged pilot . . . . . Replace.
Dirty pilot . . . . . Blow dust or lint out of pilot.
Plugged or undersized pilot orifice . . . . . Clean or replace pilot orifice.
3. Flame roll-out on start-up Blocked outlet . . . . . Check flue damper operation.
Pilot out of position (delayed ignition) . . . . Correct pilot position.
Blocked heat exchanger or flue . . . . . Clean and correct as necessary.
Refractory tile out of place . . . . . Correct or replace tile as necessary.
4. Flame has lazy yellow tip Low primary air . . . . . Correct manifold pressure according to rating
plate. Correct orifice size if necessary (see
parts list). Clean burner ports if dirty.
5. Not enough heat Inadequate gas supply . . . . . Gas meter too small. Gas line from meter to
boiler too small.
Low manifold gas pressure . . . . . Gas pressure on boiler manifold, with
Modusnap valve wide open. Should be
adjusted to 4.0" (1.0 kPa) W.C. natural gas,
9.0" (2.2 kPa) W.C. propane.
Boiler size inadequate . . . . . Replace with boiler of higher input.
6. Pump noisy Air in volute . . . . . Bleed air from volute. Check pump alignment.
Worn coupling or bearings . . . . . Replace worn parts.
7. Boiler pounding or knocking Too low water flow through boiler . . . . . Check temperature rise between inlet and
outlet boiler piping. 15°F (8°C) to 25°F
(14°C) temperature rise is recommended.
If temperature rise is over 25°F (14°C),
increase pipe size or pump capacity or locate
obstruction. Check for stuck closed zone
valves. Check for zone pumps not operating.
Check for closed valve in system.
8. Boiler condensing Low water temperature . . . . . Flue product moisture will condense at the
start-up until the boiler water temperature
reaches the normal operating conditions.
9. Pump cavities or low Defective fill valves or pressure regulator . Replace.
water pressure at boiler Oversized expansion tank . . . . . Replace.
gauge or bubbles in system Expansion tank piped incorrectly . . . . . Repipe expansion tank to suction size of pump.
at high temperature
10. Pressure relief valve opens Waterlogged expansion tank . . . . . Drain 2/3 of the water from the expansion tank.
11. Pilot is lit but main burners Boiler off on hi-limit control . . . . . Check for low water flow or hi-limit setting.
will not come on Boiler incorrectly wired . . . . . On single or multiple zone systems with zone
valves, room thermostat should be wired to
R&W terminals. For multiple zone systems with
ozone pumps, thermostats for extra zones
should be wired to R&A terminals.
Boiler off on flame roll-out switch . . . . . Remedy as in symptom #3. Reset the manual
reset switch.
Broken wire in thermostat circuit or
defective thermostat . . . . .
Check continuity through thermostat circuit with
wires disconnected from R&W.
12. Boiler short cycles Heat anticipator in room thermostat set
too low . . . . .
Increase setting (1.0 is usually satisfactory)
Low water flow through boiler . . . . . Increase size of pump or increase piping size.
Hi-limit switch may be set too low . . . . . Increase setting to at least 20°F (11°C) over
outlet water temperature.
Table 12. Troubleshooting Analysis.