LAARS Mighty Max HH (Sizes 320M - 1000M) - Installation, Operation and Maintenance Instructions - Manual (Page 24)

Page 24 LAARS HEATING SYSTEMS
Other maintenance requirements include:
1. Periodic cleaning of filters, when supplied.
2. Lubrication of moving parts (when applicable),
with the correct type and amount of lubricant.
3. Periodic examination of the venting system.
4. Periodic cleaning of vent terminal screens,
where applicable.
5. Cleaning flue gas passageways.
4D. Filter
4D-1. Filter Function
A filter has been designed into the operation of
this Mighty Max boiler. Its function is to filter the
combustion air before it is delivered to the burner
system. The filter is manufactured out of a
polyurethane foam and may be cleaned with a mild
soap and water solution. Clean the filter only after the
filter has been removed from the filter housing (see
Figure 19).
4D-2. Filter Service
(The filter does not need cleaning if this is a first
time heater start-up).
1. Turn the heater off using the toggle switch.
2. Remove the door panel and bonnet from the
jacket.
3. Remove the screws on the filter housing to
expose the filter as shown in Figure 19.
Caution
The filter has arrows which indicate the
direction of the air flow. Failure to install the
filter correctly may cause blower failure and
dangerous operation.
The filter must be inspected for contamination
one week after start-up. Depending upon the severity
of contamination, a suitable cleaning schedule may be
developed. The factory recommends cleaning the filter
at least once every 30 days. In high contamination
areas, such as construction sites, factories, etc., the
filter may need to be cleaned daily. Failure to do so
could result in lower heat output and potential unsafe
operation.
SECTION 5
Troubleshooting
5A. Sequence of Operation
To troubleshoot the heater properly you must
first understand the sequence of operation of the
heater:
1.
Upon a call for heat a 24 Vac signal is sent
through fusible links and high limit(s) to the
ignition control “TH” terminal.
2. The “IND” terminal of the ignition control is
energized for a 15 second pre-ignition purge
period during which the combustion blower
purges the combustion chamber.
3. After the purge period there is a 20 to 35 second
igniter heat up period. The glow of the igniter
can be seen through the boiler sight glass.
4. Then there is a seven second trial for ignition.
During this time the gas valves are energized and
the main burner ignites. The gas valves will
remain energized throughout the call for heat as
long as the ignition control igniter senses a
stable flame.
5. After the call for heat is satisfied the ignition
control closes the gas valves and operates the
blower for a thirty (30) second post purge cycle.
This clears the combustion chamber of
combustion products.
The ignition is attempted three times. If ignition
is not successful, the control shuts down and “locks
out”. It remains in the lockout condition until the
boiler is turned off then back on or 120 Vac power to
the boiler is interrupted.
Figure 19. Filter Exposed for Cleaning.
4. Inspect the filter for discoloration due to
contamination or any other forms of debris. If
contamination or debris exists, wash the filter in
a soap/water solution then rinse with water only.
It is important that the filter be dry before
placing it back in the filter housing.