Danfoss TTS350 - Soft Start Removal and Installation; Soft Start Removal (Closed-Top)

1. IsolatethecompressorpowerasdescribedinSection1.8ElectricalIsolationonpage22.
2. RemovetheSoftStart.RefertoSection4.14.4SoftStartRemoval(Closed-Top).
3. FliptheSoftStarttoaccessthefuses.RefertoFigure4-98SoftStartFuseLocationsonpage116for
detailonthefuselocations.RefertoTable4-24SoftStartFuseDetailsforfusedetail.
4. Usingamultimetersetforresistancemeasurements,placetheleadsontheendsoftheF1fuse.The
readingshouldbelessthan1Ω.
l
AnopenF1fusemayindicateaproblemwiththePottedDC-DC
5. Usingamultimetersetforresistancemeasurements,placetheleadsontheendsoftheF2Nanofuse.
Thereadingshouldbelessthan1Ω.
l
AnopenF2fusemayindicateaproblemwiththePottedDC-DC
6. Usingamultimetersetforresistancemeasurements,placetheleadsontheendsoftheF3Nanofuse.
Thereadingshouldbelessthan1Ω.
l
AnopenF3fusemayindicateaproblemwiththeClosed-TopSoftStartCircuitBoard
7. Usingamultimetersetforresistancemeasurements,placetheleadsontheendsoftheF6Nanofuse.
Thereadingshouldbelessthan1Ω.
l
AnopenF6fusemayindicateaproblemwiththeClosed-TopSoftStartCircuitBoard
8. Usingamultimetersetforresistancemeasurements,placetheleadsontheendsoftheF4orF5fuses.
Thereadingshouldbearound30-38Ωforeitherfuse.
l
AnopenF4orF5fusemayindicateaproblemwiththeClosed-TopSoftStarttransformers,circuit
board,orfan
Table 4-24 Soft Start Fuse Details
Fuse Amperage Resistance (Ω) Circuit Class Comments
F1 2A Lessthan1Ω HVDCtoDC - FastActing
F2 0.25A Lessthan1Ω TransformerSecondary-15VACtoDC-DC - FastActing,Nano
F3 1A Lessthan1Ω TransformerSecondary-SoftStartBoard - FastActing,Nano
F4 0.25A 30-38Ω HVACtoTransformer ClassCC SlowBlow
F5 0.25A 30-38Ω HVACtoTransformer ClassCC SlowBlow
F6 1A Lessthan1Ω TransformerSecondary-SoftStartBoard - FastActing,Nano

9. Troubleshoottodeterminethecauseoftheblownfuse,ifnecessaryreplaceanyfusethatisfoundto
bedefective.Someofthefusesmayrequiretheuseofneedle-nosepliersorforcepstoreplacethem.
Referto5.5.2.6DeterminingtheCauseofBlownSoftStartFuses(Closed-TopSoftStartOnly)onpage
272.
10. InstalltheSoftStart.RefertoSection4.14.6SoftStartInstallation(Closed-Top)onpage121.
11. Installthetopcovers.RefertoSection4.1CompressorCoversonpage52.
12. Returnthecompressorbacktonormaloperation.
4.14.3 Soft Start Removal and Installation
ThissectioncoversthedirectreplacementofaSoftStart(i.e.,Open-TopSoftStarttoOpen-TopSoftStartorClosed-
TopSoftStarttoClosedTopSoftStart).IfyouareupgradingtoanOpen-TopSoftStartfromaClosed-TopSoftStart,
besuretoreviewthesparepartinstructionsthatareincludedintheupgradekit.
4.14.4 Soft Start Removal (Closed-Top)
1. IsolatethecompressorpowerasdescribedinSection1.8ElectricalIsolationonpage22.
2. RemovetheSoftStartTemperatureHarness.RefertoFigure4-99Closed-TopSoftStartJ9Connectoron
page118.

M-SV-001-EN Rev. H-1/23/2023 Page 117 of 294