Sunlu FilaDryer S4 4-Spool Filament Dryer

Sunlu FilaDryer S4 4-Spool Filament Dryer

By Sunlu · Filament Dryers · 3D Printing

  • 4 spools, 1 kg each
  • 350W heater, up to 70°C
  • Community consensus pick for Bambu Lab AMS setups

Lowest price seen
$116.99
from $116.99 at Sunlu (official store) · Checked Sep 28, 2026

Prices are snapshots. Check the current price with the store.

Problems, parts and running costs

Summary

A four-spool chamber dryer for filament that needs drying in batches. Check your materials before buying: the whole chamber shares one temperature, so every roll you load has to tolerate the same setpoint.

Strengths

  • Dries three or four rolls in one cycle instead of one at a time.
  • Reached 70 C in under five minutes in independent testing.
  • Eight outlets feed up to four printers at once.
  • Documented print-quality gain on moisture-sensitive TPU after 5 hours at 55 C.
  • Preset selection on the touch screen is simple and more responsive than the S2’s.
  • The chamber rollers are described as user-replaceable.

Weaknesses

  • One shared chamber temperature, so mixed materials cannot be dried together.
  • The 70 C ceiling rules out materials that need higher drying temperatures.
  • Fans are noisy while running, and closing the lid only helps so much.
  • The humidity readout measures chamber air, not moisture inside a roll.
  • Drying did not rescue an old NinjaFlex roll and only partly recovered a PETG roll.
  • Direct feeding without the guide tube can add drag and tension.

Verified specifications

ModelSUNLU FilaDryer S4, the base model rather than the S4 Pro.
Capacityup to four 1 kg spools.
Chamber internal dimensions450 x 210 x 211 mm.
Body dimensions458 x 218 x 312 mm.
Net weight4.8 kg; gross 5.5 kg.
Maximum temperature70 C / 158 F, with an advertised drying range of 35-70 C.
Temperature uniformitywithin plus or minus 3 C, claimed, using two side fans plus a bottom heating fan.
Rated power300 W on the spec table; the marketing copy describes a 350 W PTC heater.
Measured drawabout 400 W while heating and about 80 W to hold temperature.
Humidity controlautomatic, heating from a set 30-50% RH and stopping at 25%.
Filament outletseight, enough to feed up to four printers.
Supported diameters1.75 mm, 2.85 mm and 3.0 mm.
Maximum spool width75 mm, with two spools loaded per section.
Controlsfront touch screen with presets for PLA, ABS, PETG, PA and PC.
Modestimed drying and a moisture-control mode that cycles heating to hold humidity.
CertificationsETL, CE-EMC, CE-LVD, FCC and RoHS.
Warranty12 months.
Includedtwo 1 m PTFE guide tubes, four 8 cm pieces and documentation.
Full research notes and sources

Drying results and what they mean

The evidence for actual drying is real but narrow. One reviewer soaked a roll of TPU for a week, printed a test model, then dried the roll and reprinted it; a boat printed after 5 hours at 55 C was visibly better with the slice settings unchanged. A second outlet reports the same result but notes it came from a pre-release unit. The same testing found only modest gains on matte PLA, an old NinjaFlex TPU roll that stayed unusable, and a PETG roll that went from never printing to printing with residual stringing and bubbles. Drying helps moisture-sensitive filament and does not rescue every neglected spool.

Fit, spools and routing

Rated capacity is four spools, two per section, up to 75 mm wide. But chamber dimensions are not a fit guarantee: one bulk 3 kg spool did not fit in testing, standard 1 kg and 750 g rolls were workable, and cardboard spools were awkward when nearly empty. One reviewer physically packed six 1 kg spools inside, which says the chamber is roomy but says nothing about airflow in that configuration. Measure your actual spools, including rim adapters, before buying. Feed filament through the supplied PTFE tubes rather than directly; one setup developed excessive tension feeding without the tube, and direct feeding worked only from the outlets nearest the printer.

Noise and running costs

The fans are audible. One reviewer finds them noticeably loud, another calls the unit better suited to a printing room than a bedroom or a desk where you take calls, and neither could find a silent mode or fan-speed control. Running cost is electricity, and the numbers to use are the measured ones rather than the nameplate: about 400 W during heat-up and about 80 W to hold. Actual energy per cycle was not measured, so the honest approach is a plug-in energy meter. Desiccant and sealed storage are still recommended for rolls kept outside the dryer.

Reliability and warranty

Reliability data is the weakest part of the record. No source provides a failure rate or a multi-year owner history, and one reviewer states plainly that the available evidence does not establish the base model’s long-term failure rate. The rollers are described as user-replaceable, but no replacement-parts list was found. SUNLU’s own warranty statement lists the S4 by name at a 12-month term for both consumer and business channels, with repair or replacement for quality issues and parts purchase for out-of-warranty self-repair. The same page scopes the policy to SUNLU’s domestic sales channels, so a US buyer should confirm applicability before relying on it.

Which model this is

This page covers the SUNLU FilaDryer S4 base model, sold under ASIN B0CX4QJL8F in white, black and grey. Do not merge it with the S4 Pro, which has two independent temperature zones and an 85 C maximum, or with the S2, SP2, E2 and FilaDC i10, which are separate products. The base S4 has a single chamber temperature and a 70 C ceiling.

Sources

Manufacturer:

Independent reviews:

Owner reports:

Buying guides for this category

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