Keller LevelRat Level Transmitter

Fits submersible liquid-level loops that need a relative range between 0…5 and 0…100 ftWC with 4–20 mA or voltage output, optional RS485, IP68 cable probe construction, and optional UL/cUL intrinsically safe builds.

Key advantages

Custom relative ranges — infinite between 0…5 and 0…100 ftWC (psi / inWC / ftWC).
Static ±0.25 %FS — Total Error Band ±0.5 %BR in the compensated range.
Output mix — 4–20 mA IS; 4–20 mA + RS485; 0–5 / 0–10 VDC + RS485.
Kynar non-fouling diaphragm option — 316L std / titanium optional; IP68 submersible cable probe.

Typical applications

Wastewater and lift-station level with non-fouling diaphragm needs.
Tank and reservoir level where ranges are specified in ftWC.
IS-approved 4–20 mA level loops in classified sumps.

Selection guide

Range — Relative infinite between 0…5 and 0…100 ft WC (psi / inWC / ftWC custom). Basic ranges 1 and 3 bar relative (proof 2 and 5 bar).
Accuracy — Static ±0.25 %FS; Total Error Band ±0.5 %BR (compensated range).
Output — 4–20 mA IS-approved; 4–20 mA + RS485 (with/without lightning protection); 0–5 / 0–10 VDC + RS485.
Supply — 11…30 VDC (4–20 mA IS); 11…32 VDC (4–20 mA+RS485 w/ LP); 8…32 VDC (4–20 mA+RS485 w/o LP / 0–5 V); 13…32 VDC (0–10 V).
Process / electrical — Submersible cable probe; optional 1/2" NPT conduit fitting accessory. Integral cable (PE/EPDM, Hytrel/Viton, or Tefzel options); braided shield to housing.
Wetted / housing — 316L stainless steel standard; optional titanium; Kynar non-fouling diaphragm; cable seals PE/EPDM or Hytrel/Viton/Tefzel.
Ingress — IP68.
Ambient — Operating −10…60 °C; compensated 0…50 °C.

Common mistakes

Ordering a span outside 0…5 to 0…100 ftWC without confirming custom engineering with the RFQ.
Mixing IS vs non-IS supply windows (11…30 VDC IS vs wider non-IS windows) and cable barrier requirements.
Ignoring cable seal chemistry (PE/EPDM vs Hytrel/Viton vs Tefzel) vs process media.
Assuming a local display — this SKU lists display: none.
Expecting a published media-temperature row from this page — that field is empty in our JSON; send process temperature in the RFQ.
Skipping lightning-protection option when the site has surge exposure on long cable runs.

When to RFQ / what to tell us

Level span (ftWC / psi / inWC) and fluid SG if converting head to pressure.
Output (4–20 mA IS / 4–20 mA+RS485 / voltage+RS485) and whether lightning protection is required.
Cable length, seal material, and optional 1/2" NPT conduit fitting / weight / spacer.
Housing material (316L vs titanium) and diaphragm (standard vs Kynar).
Area classification (UL/cUL IS yes/no), quantity, ship-to country.
Process/media temperature (not published as a separate JSON field — state it on the RFQ).

Request a Quote · Get selection help

Specs

Spec	Value
SKU	33971
Brand	Keller
Model	LevelRat
Product type	level_transmitter
Measuring range	Relative infinite between 0…5 and 0…100 ft WC (custom units)
Accuracy	Static ±0.25 %FS; TEB ±0.5 %BR (compensated)
Output signal	4–20 mA IS; 4–20 mA + RS485 (± lightning protection); 0–5 / 0–10 VDC + RS485
Supply voltage	11…30 VDC (4–20 mA IS); 11…32 / 8…32 / 13…32 VDC by output option
Process connection	Submersible cable probe; optional 1/2" NPT conduit fitting
Electrical connection	Integral cable (PE/EPDM, Hytrel/Viton, or Tefzel); braided shield
Wetted materials	316L SS std; optional titanium; Kynar non-fouling diaphragm
Housing	316L stainless (optional titanium)
IP rating	IP68
Ambient	Operating −10…60 °C; compensated 0…50 °C
Process pressure	Relative to 100 ftWC; basic 1 and 3 bar relative (proof 2 and 5 bar)
Communication	Optional RS485 KELLER-bus / Modbus RTU (up to 128 nodes)
Display	none
Hazardous area	UL/cUL IS versions available (4–20 mA IS)
Approvals	CE; UL/cUL Class I Div 1 A–D; Class II Div 1 E–G; Class III (4–20 mA IS)
Mounting	Submersible; optional protective spacer / stabilizing weight
Notes	Specs from Keller LevelRat datasheet Edition 06/2026. Lightning protection lifetime guarantee on 4–20 mA models.

Documents

Keller LevelRat datasheet (PDF) — request the current OEM PDF on RFQ (no direct public PDF URL stored for this SKU).

FAQ

Q: What level ranges are available? A: Relative ranges infinitely configurable between 0…5 and 0…100 ftWC (psi / inWC / ftWC custom). State the span in the RFQ.

Q: Which outputs and IS options exist? A: 4–20 mA IS-approved; 4–20 mA + RS485 with/without lightning protection; 0–5 / 0–10 VDC + RS485. UL/cUL IS applies to the 4–20 mA IS builds listed in the datasheet.

Q: Is there a local display? A: No — display is listed as none. Readout is via the loop / RS485 host.

Q: What should I send for a quote? A: Span, output, cable/seal, material, IS need, process temperature, quantity, ship-to. Compatible with systems using Keller LevelRat — we do not claim authorized-dealer status.