ARO 66610X Diaphragm Codes 4 and 6: Check the Assembly and Kit

On the ARO 66610X-X-C 1-inch metallic pump family, diaphragm codes 4 and 6 identify different assemblies. Code 4 is PTFE/Santoprene; code 6 is Composite PTFE. A request for “a PTFE diaphragm” therefore leaves an important purchasing question unanswered. Match the complete pump configuration to the applicable parts list before releasing an order.

This guide explains a specific identification check, not a conversion or installation procedure. Its scope is the configurations covered by the ARO 66610X-X-C operator’s manual cited below. Do not extend these part numbers to every ARO pump beginning with 6661.

Read the code position, not just the character

The three material positions in the final group identify the seat, ball and diaphragm, in that order. Their meaning depends on their position. In the cited manual, 6 in the ball position means Acetal, while 6 in the diaphragm position means Composite PTFE.

When requesting a part, retain the entire nameplate code, including separators and the final suffix. If the last material group ends in 4, check the code-4 diaphragm assembly. If it ends in 6, check the code-6 assembly and its associated notes. Do not interpret an isolated “6” or a shortened warehouse description as a complete specification.

Code 4: identify both the PTFE diaphragm and its backup

For the code-4 configuration, the manufacturer’s fluid-section parts table identifies 93459-4 as the PTFE diaphragm and 92973-B as the Santoprene backup diaphragm. These are separate references within the assembly.

A purchasing line that lists only the PTFE part does not tell the supplier whether the backup diaphragms are also required. State the intended scope explicitly: individual diaphragms, both diaphragm types, or a confirmed fluid-section service kit. Record quantities against each part number rather than relying on “one set,” which can be interpreted differently.

Code 6: distinguish diaphragm 48490056 from conversion kit 48495964

For the Composite PTFE configuration, the manual lists diaphragm 48490056. It also shows 48495964 in the parts table, but the footnote is essential: this is a conversion kit, not a service kit. The stated purpose is conversion from a standard pump to a one-piece diaphragm pump.

The conversion kit does not include balls, seats or the Y328-126 O-ring. Do not order it as a complete fluid-section overhaul package, and do not infer a different kit number by inserting a diaphragm code into a familiar numbering pattern. A table column heading does not replace its configuration-specific footnote.

The manual also gives configuration-specific connecting-rod and shim information for -XX6-C pumps and refers users to separate composite-diaphragm instructions. Those details are a reason to check the whole assembly. They are not a basis for declaring code 4 and code 6 directly interchangeable.

Keep replacement and conversion requests separate

For a like-for-like repair, the goal is to identify what is fitted and order the specified replacement components. For a proposed material or diaphragm-design change, the question is broader: which complete configuration and supporting components are required, and is it suitable for the duty?

Do not treat the word PTFE as proof of identical construction, fit, service procedure or operating limits. Give the manufacturer or supplier the liquid, concentration, operating and cleaning temperatures, and relevant service conditions when reviewing a change. A parts-identification article cannot establish chemical compatibility or approve a conversion.

Keep the pump isolated under the applicable site procedure while any physical inspection is performed by qualified personnel. Use the exact manufacturer instructions for disassembly and assembly; no torque settings or installation sequence are implied here.

Send an unambiguous ARO diaphragm enquiry

Attach a clear nameplate photograph and include these details in the request:

1. Full model: copy every character and suffix, plus the serial number when available.
2. Document: identify the operator’s manual and revision used for the parts lookup.
3. Diaphragm position: state whether the complete material code ends in 4 or 6; do not send only “PTFE.”
4. Requested scope: list each verified part number and quantity, or ask for the exact contents of the proposed kit.
5. Installed condition: disclose known modifications or any mismatch between the nameplate and existing components.
6. Order decision: state whether you need a like-for-like replacement or a separately reviewed configuration change.

If the part marking, nameplate and manual disagree, keep the order on hold until the difference is resolved. Photographs can support identification, but appearance alone does not confirm diaphragm material or compatibility.

Common ordering questions

Are code 4 and code 6 both simply PTFE diaphragms?

Both descriptions include PTFE, but the manual identifies different assemblies: code 4 is PTFE/Santoprene and code 6 is Composite PTFE. Use the configuration-specific parts list rather than treating the descriptions as interchangeable.

Is 48495964 a complete composite-diaphragm service kit?

No. The Rev AT manual identifies it as a conversion kit, not a service kit, and excludes balls, seats and the Y328-126 O-ring. For routine repair of an existing composite-diaphragm pump, identify the required replacement parts from its applicable parts list.

Does this guide apply to all 6661-series pumps?

No. The scope is the 1-inch metallic configurations covered by the cited 66610X-X-C manual. Other 6661 families have separate manuals and service-parts references.

References and next checks

Technical source: ARO 66610X-X-C operator’s manual 81376642, Rev AT, revised September 25, 2026, pages 2, 4 and 5. This is the manual linked from the official ARO 1-inch PRO Series metallic pump page when checked on November 5, 2026. Use the current instructions applicable to the actual pump; the separate conversion instructions referenced by ARO must also be obtained before any conversion is considered.

For the wider maintenance scope, read ARO repair-kit contents and valve-seat checks and use the تکنیکی لائبریری to locate the relevant manual. Send WILLEE the full model and requested parts for identification and quotation. Catalogue references do not establish stock availability, delivery time or approval of a configuration change.