HP SU-2A - Manual (Page 13)

13
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 Solutions
1. Burner motor runs and:
No flame after pre-purge & no fuel indicator (where
applicable)
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.
No flame, fuel indicator on (where applicable),
faulty ignition transformer or spark separately
Check ignition transformer, electrode, cracked
electrode or gap. Fix or replace.
Fenwal control defective after above tests. Replace
2. Burner locks out after 4 seconds
First, check ionization electrode, ionization cable
(for cracks) and boot. Fix as needed.
Polarity reversed Check power feed for broken polarity
Bad earth grounding Fix the ground wire
Gas pressure is too low Check the gas pressure and adjust to proper pressure
3. Pulsation at start
First, check the burner head location with respect to
the end of the flame tube. Adjust as necessary.
Gas pressure is too high. Use manometer and readjust the pressures.
Blocked Flue Check draft and clear flue of foreign materials.
4. Pulsation during operation
Burner is not correctly adjusted. Readjust with combustion analyzer.
The burner is dirty. Clean the burner.
Defective chimney Check and change if necessary with liners.
5. Burner locks out
Ionization current is too low. Check current. Minimum 0.8 micro amps. Check
position of ionization electrode and the condition of
the cable.
6. The CO content is too high
Excess air is too high or too low. Adjust air shutter.
The gas holes are clogged. Clean them.
The fresh air intakes are too small. Check and readjust.
The burner head is out of position. Check and readjust.
7. Condensation in the heat exchanger
Firing Rate is too low. Increase the firing rate so that the stack temperature
is 350 o F or HIGHER. Insulate the chimney.