Trane GXAA, Инструкция по установке, эксплуатации и обслуживанию

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38 MUA-SVX006B-EN
High Limit and/or Safety Limit Maintenance
Single furnace units are equipped with a primary high limit on the upstream side of the heat
exchanger and a secondary high limit on the downstream side of the heat exchanger. Multiple
furnace units are equipped with a primary high limit on each furnace section and a secondary
high limit on the downstream unit. The primary high limit is a disk type switch while the
secondary high limit is a capillary switch. To service or replace high limit or safety limit:
1. Turn off the manual gas valve and electrical power to the MS unit.
2. To access the high limits, remove the four screws from the top of the raceway on each
furnace section and swing the raceway down. The primary limit can be removed by removing
the two screws holding the high limit bracket to the heat exchanger and removing the bracket
and limit assembly from the heat exchanger. Note location of and remove wires from limit
switch, then remove push nuts and springs holding limit switch to bracket. Re-assemble in
reverse order making sure that parts are assembled so that spring pressure holds limit switch
securely against bottom header plate of heat exchanger.
3. To remove the secondary high limit, remove the wires from the limit switch, remove the
screws and stand-off sleeves holding the limit switch body to the mounting plate. D Do o n no ott
rre em mo ov ve e tth he e ssccrre ew wss h ho olld diin ng g tth he e m mo ou un nttiin ng g p plla atte e tto o tth he e h he ea att e ex xcch ha an ng ge err.. Slowly pull the
switch and capillary assembly out of the retaining tube, taking care to prevent kinking the
capillary tube. Re-assemble in reverse order, carefully pushing the capillary tube into the
retaining tube to prevent kinking the capillary tube.
4. Complete appropriate start-up procedure as given in the “Start-Up” section of this manual.
5. Check Burner Adjustment.
6. Check gas control valves and pipe connection for leaks.
7. Check operation of auto gas valve.
8. Check operation of safety devices.
9. Inspect and service blower section of system.
Seasonal Maintenance
The unit should be thoroughly checked before the start and at the end of each heating and
cooling season.
1. Motors and belts should be inspected.
2. Tighten belts if loose.
3. Check and clean DX or Chilled Water coil twice yearly, if unit is so equipped per
manufacturer’s service manual. Chilled Water coil must be winterized at beginning of heating
season (i.e. drain water from coil per manufacturer’s instructions).
4. Check air throughput at beginning of heating season to confirm unit operation is within the
specified temperature rise range.
5. At beginning of heating season clear Condensate Drain Pan and P-trap of water if unit is
equipped with DX or Chilled water coil. Clean out drain pan and fill P-trap with a non-toxic
glycol solution.
6. Evaporative cooler must be cleaned and maintained per manufacturer’s instruction
frequently during the operating season.
7. Inspect Control Dampers during periodic maintenance. Damper pivot points should be
cleaned to ensure free damper operation.
8. Blower wheels should be checked periodically for dirt build-up on blades. Clean as required.
Filters
The filter section has been designed to incorporate (as standard) one-inch washable filters. Other
optional filter types are also available: two-inch washable throwaways; or one or two inch hi-
efficiency 30% pleated filters.
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