Troubleshooting - Heat Wise SU-2A Manual

Trouble shooting:
There are three factors to operate the gas burner properly:
1. Electricity {(main Power 120V/60 Hz /1 Ph)( secondary 24V)}
2. Gas flow (Incoming pressure should be 10" w.c. with proper gas line without pressure drop
during burner operation).
3. Combustion air.
Check these three items properly before proceeding in detail for other problems.
Condition
Burner motor runs and:
No flame after pre-purge & no fuel indicator (where
applicable)
No flame, fuel indicator on (where applicable),
faulty ignition transformer or spark separately
Fenwal control defective after above tests.
Burner locks out after 4 seconds
Polarity reversed
Bad earth grounding
Gas pressure is too low
Pulsation at start
Gas pressure is too high.
Blocked Flue
Pulsation during operation
Burner is not correctly adjusted.
The burner is dirty.
Defective chimney
Burner locks out
Ionization current is too low.
The CO content is too high
Excess air is too high or too low.
The gas holes are clogged.
The fresh air intakes are too small.
The burner head is out of position.
Condensation in the heat exchanger
Firing Rate is too low.
When commissioning the burner, make sure the gas control
knob is in the "ON" position. Install monometers at the
inlet pressure tap and outlet pressure tap. Note: When
checking manifold pressure, do not subtract burner
housing pressure during valve-on delay. Record the static
incoming gas pressure. When the burner lights off, record
the running incoming gas pressure; the running incoming
gas pressure should never be below 5". Note: this pressure
drop should not be greater than 1".
Check the manifold pressure from the outlet pressure tap.
Refer to Charts 3 and 4 on page 7 to make sure the gas
pressure is set for the appropriate fuel and pressure. If
adjustments need to be made, remove the cap screw and
adjust the pressure regulator. Screwing the regulator
clockwise will increase the manifold pressure and
counter-clockwise will decrease the manifold pressure.
Solutions
Check 24V feed to airflow switch & after airflow switch to
control. Fix or replace the airflow switch. If there is no
secondary power, then replace the 24Vtransformer.
Check ignition transformer, electrode, cracked electrode or
gap. Fix or replace.
Replace
First, check ionization electrode, ionization cable (for cracks)
and boot. Fix as needed.
Check power feed for broken polarity
Fix the ground wire
Check the gas pressure and adjust to proper pressure
First, check the burner head location with respect to the end of
the flame tube. Adjust as necessary.
Use manometer and readjust the pressures.
Check draft and clear flue of foreign materials.
Readjust with combustion analyzer.
Clean the burner.
Check and change if necessary with liners.
Check current. Minimum 0.8 micro amps. Check position of
ionization electrode and the condition of the cable.
Adjust air shutter.
Clean them.
Check and readjust.
Check and readjust.
Increase the firing rate so that the stack temperature is 350
or HIGHER. Insulate the chimney.
10
o
F