LAARS Mini-Therm JVS (Sizes 50-225) - Install and Operating Manual - Manual (Page 33)

Mini-Therm JV Page 33
# Symptom Cause Remedy
1 Pump not operating No power . . . . .
Pump defective . . . . .
Incorrectly wired . . . . .
Check circuit breakers and power source. Replace. 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. . . . 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 water
pressure at boiler gauge or
bubbles in system at high
temperature
Defective fill valves or pressure
regulator .
Replace.
Oversized expansion tank . . . . . Replace.
Expansion tank piped incorrectly
. . . . .
Re-pipe 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
will not come on
Boiler off on hi-limit control . . . . . Check for low water flow or hi-limit setting.
Boiler incorrectly wired . . . . . On single or multiple zone systems with zone valves, room
thermostat should be wired to T-T terminals. For multiple
zone systems with ozone pumps, thermostats for extra
zones should be wired to R&A terminals.
Broken wire in thermostat circuit
or defective thermostat . . .
Check continuity through thermostat circuit with
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.