Water Filter for the LG LFX28978ST (LT700P)

LFX28978ST specifics — where the filter actually lives

On the LFX28978ST, the cartridge in the fresh-food compartment, typically the upper back wall in most French-door layouts, a spot that survives trim changes across the LF run. Mechanically it is a push-and-twist seat: the cartridge locks with a short rotation after seating; if it rotates freely, it is not seated.

Two quirks worth knowing before you order: plan on a towel for the first pull — sitting water in the line — and a five-second reset hold once the fresh cartridge is in. The LF in LFX28978ST is doing real work: it places the machine in LG’s French-door family, which pins down the cartridge line, the reset behavior, and the service documentation worth consulting. That ST suffix is trim-level shorthand. LG kept the LT700P bay common to every finish in the line.

LF vs LS — what the prefix tells you

Know your LF from your LS and the cartridge question halves: split by cabinet mission (French-door versus side-by-side), joined by cartridge line — that is the LF/LS story. the 28 cu ft figure in the code is the household size proxy; larger households breach the rated gallons before the calendar does.

Swap it in 5 minutes

• Press the release (if fitted), twist the old cartridge free, and pull it from the header.
• Wet the new cartridge’s o-ring with cold tap water so it seats without dragging.
• Push the cartridge square onto the header, then give it the locking quarter turn.
• Run two gallons through the dispenser to flush carbon fines, then hold the filter-reset control until the status light clears.

What this filter takes out of your water

Coverage above lists what the standard addresses, not a performance claim for any specific cartridge — removal claims vary by certificate, so check the NSF listing for the exact part number you are buying.

LFX28978ST filter questions