The PURE Humidifier ER Series is a small-capacity electric humidifier built for environmental rooms and chambers, with a capacity up to 21 lbs/hr, made by PURE Humidifier Co. of Chaska, Minnesota — a commercial and industrial humidification manufacturer, not to be confused with Pure Enrichment, the consumer humidifier brand. This guide covers how to identify your ER unit and which parts we stock are commonly used on it.
What the ER Series is and where it's used
The ER Series is rated up to 21 lbs/hr. Like the rest of the PURE line, it uses SCR (silicon-controlled rectifier) modulation to hold humidity within about ±1–2% RH, and disperses steam through straight injection tubes or PURE's Fast-Pac or Insty-Pac dispersion assemblies. Instead of a side-entry heater assembly, its cabinet opens by removing a cover fastened with cover clamps and a clamp bar — the feature most likely to catch your eye if you're used to PURE's larger units.
ER vs. ERDDR: how to tell which one you have
Check the model string on the nameplate: if it ends in “DDR,” you have the deionized/demineralized (or reverse-osmosis) water version. If not, you have the standard-water base model.
Base-model ER units use Tri-Probe electrode water-level control and a motorized brass drain valve. ERDDR units run on DI/RO water instead, using a stainless float-operated fill valve, a stainless float-operated low-water cutoff, a stainless overflow standpipe, and a stainless manual ball-valve drain in place of the Tri-Probe electrodes and motorized drain valve. The two variants don't share water-level or drain parts — check your nameplate before ordering.
How to tell it apart from PURE's other series
- ES Series: the ES is a larger side-entry electric steam unit rated up to 306 lbs/hr, well above the ER's 21 lbs/hr.
- EC Series: the EC is a cabinet-style unit for wall mounting, rather than the ER's removable, clamp-fastened cover.
- GX Series: the GX is gas-fired (natural gas or propane) rather than electric.
- SX Series: the SX produces steam from boiler steam via a heat exchanger rather than heating water electrically.
Replacement parts we stock for the ER Series
The parts below are commonly used on the ER Series based on PURE's published documentation. Confirm against your unit's nameplate and O&M parts list before ordering — PURE has made design changes across production runs.
Base-model (ER) parts
- 09142 — Normally Closed Drain Valve Z2075Q-K + CQKB24-RR — motorized brass drain valve, normally closed.
- 09143 — Normally Open Drain Valve Z2075Q-K + CQKB24-LL — motorized brass drain valve, normally open.
- 15166 — Tri-Probe O-Ring — O-ring for the Tri-Probe electrode assembly.
- 15164 — Flusher O-Ring — O-ring for the surface water flusher.
- 15930 — Cover Clamp — clamp that secures the removable cover.
- 15522 — Cover Clamp Screw — screw used with the cover clamp.
- 15524 — Cover Clamp Clip-On Nut — clip-on nut used with the cover clamp.
- 15841 — Clamp Bar Screw — screw used with the clamp bar.
- 15702 — Clamp Bar Nut — nut used with the clamp bar.
- 15520 — Black EPDM Peroxide-Cured "E" Cover Gasket — EPDM cover seal (also used on EC cabinet units).
DDR-model (ERDDR) parts
- 09079 — DDR Float Ball & Arm Assembly, Small — float ball & arm (small) for the DDR fill valve.
- 09030 — DDR Float Ball & Arm Assembly, Big Orifice — float ball & arm (big orifice) for the DDR fill valve.
- 05052 — DDR Water Inlet / Float Plate Gasket — gasket for the DDR water inlet / float plate.
- 09128 — KIP 1/4" SST Fill Valve 2X2599-24/50-60 — stainless float-operated fill valve.
- 15048 — Liquid Level Switch, Vertical, 1/4" (9871-09490) — float-operated low-water cutoff switch.
Control, safety and maintenance items used across the PURE line
Not specific to one series — commonly used across PURE's ES, EC, ER, GX and SX units.
- 15047 — Over Temp Switch SE-L250M — over-temperature safety cutoff switch.
- 12354 — SCR Relay, Crydom HD6050TH S1 — SCR modulation relay.
- 15184 — #12 Zinc SAE Washer (FW#12Z) — hardware washer.
- 16300 — PUREClean Descaler, 45 lb — descaling treatment for periodic maintenance.
Where to find the official parts list and manual
We haven't reproduced PURE's numbered parts diagrams here. For the definitive parts list, use the factory O&M manual, which contains the numbered parts list and diagram for your unit:
Before you order
Confirm your unit's exact model and serial number from its nameplate before ordering — base and DDR models don't share water-level or drain parts. See our guide to OEM vs. aftermarket HVAC parts, browse everything we stock in our PURE Humidifier replacement parts collection, or contact us with your model and serial number and we'll help confirm fit.
Frequently Asked Questions
Is an ERDDR part interchangeable with an ER part?
No. The ERDDR uses DI/RO-water components — a stainless float-operated fill valve, float-operated low-water cutoff, and manual ball-valve drain — while the base ER uses Tri-Probe electrode water-level control and a motorized brass drain valve. Confirm from your nameplate before ordering.
Which PURE series makes steam from boiler steam instead of heating water?
The SX Series is a steam-to-steam heat exchanger — it uses existing boiler steam to produce clean humidification steam.
Where is the model number on a PURE ER?
Check the nameplate on the unit itself, and cross-reference it against your unit's O&M manual — we haven't verified one universal nameplate location across every ER production run, so we point you to the nameplate and manual rather than guess. If you can't locate or read it, contact us and we'll help.
This unit involves line-voltage electrical components and live steam. Service should be performed only by qualified personnel, following PURE Humidifier Co.'s O&M manual and your facility's electrical lockout/tagout procedures.