Check Flame Signal; Review With Owner; Cleaning Boiler Heat Exchanger - Lochinvar FTxl 500 Service Manual

2
Maintenance

Check flame signal

1. At high fire the flame signal shown on the display should
be at least 10 microamps.
2. A lower flame signal may indicate a fouled or damaged
flame sense electrode. If cleaning the flame sense electrode
does not improve, ground wiring is in good condition,
and ground continuity is satisfactory, replace the flame
sense electrode.
3. See Section 3 - Troubleshooting in this manual for other
procedures to deal with low flame signal.

Review with owner

1. Review the FTXL User's Information Manual with the
owner.
2. Emphasize the need to perform the maintenance schedule
specified in the FTXL User's Information Manual (and in
this manual as well).
3. Remind the owner of the need to call a licensed contractor
should the boiler or system exhibit any unusual behavior.
4. Remind the owner to follow the proper shutdown
procedure and to schedule an annual start-up at the
beginning of the next heating season.

Cleaning boiler heat exchanger

For recommended materials; including brush, appropriate
extension(s), refractory cover, and detailed instructions see
Table 2-2 - Heat Exchanger Cleaning Kits.
1. Shut down boiler:
• Follow the "To Turn Off Gas to Appliance" instructions
for the boiler in Section 10 - Startup of the Installation
and Operation Manual.
• Do not drain the boiler unless it will be exposed to
freezing temperatures. If using freeze prevention fluid
in system, do not drain.
2. Allow time for the boiler to cool to room temperature if
it has been firing.
3. Remove the bezel from the unit.
4. Remove the screw securing the fan and venturi from the
fan plate and set aside.
5. Remove the nuts securing the fan plate and burner from
the heat exchanger plate and set aside (FIG. 2-2).
6. Loosen the heat exchanger bolts to remove the heat
exchanger top plate (FIG. 2-2).
The boiler contains ceramic fiber
WARNING
materials. Use care when handling these
materials per instructions on page 3 of
this manual. Failure to comply could
result in severe personal injury.
(continued)
7. Disconnect the condensate hose from the condensate trap
8. Use a vacuum cleaner to remove any accumulation on the
9. Using a clean cloth dampened with warm water, wipe out
10. Allow the heat exchanger to thoroughly dry.
11. Reinstall the condensate hose, heat exchanger top plate,
12. Perform a combustion analysis by following the instructions
13. Resume operation.
Table 2-2 Heat Exchanger Cleaning Kits
Service Manual
and route to drain.
boiler heating surfaces. Do not use any solvent.
the combustion chamber. Rinse out debris with a low
pressure water supply.
burner, fan plate, fan, venturi, and bezel (FIG. 2-2).
in Section 3 - Troubleshooting - Combustion Analysis
Procedure on pages 47 and 48.
Kit Part
Model
Number Number
CTN7721
MSC20085
MSC20086
400 - 850 KIT30098
MSC20206*
MSC20207*
* Do NOT use a metal brush. Only use
CAUTION
the kit provided brush or an equivalent
replacement nylon brush.
Component
Description
Carton
1/4" x 12" Drill Extension
1/4" x 24" Drill Extension
Nylon End Brush
Nylon Cup Brush
35