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How to specify an Expansion Valve

What to put on an RFQ for Expansion Valve: the ratings, documents, and constraints that change the quote.

25 Oct 2026 · 3 min read · Tradinor Desk

Specification points for Expansion ValveTRADINOR · FIGUREWhat to lock for Expansion ValveCapacityAir or waterElectricalRefrigerant or fuel
Put these on the RFQ for Expansion Valve before you compare prices.

A buyer searching for Expansion Valve is usually trying to stop a bad substitute. HVAC equipment is specified by capacity at a stated condition, the refrigerant or fuel, the air or water flow, and the noise. The notes below are selection criteria for an Expansion Valve. They are not a catalog promise. Confirm every rating on the current datasheet, drawing, or test report for the revision you will receive.

What has to be true of Expansion Valve

HVAC equipment is specified by capacity at a stated condition, the refrigerant or fuel, the air or water flow, and the noise. For an Expansion Valve, start from the duty, then the interface to the rest of the machine or the room, then the document that proves the claim. A lower price that leaves one of those blank is a different product.

Expansion Valve is easy to confuse with Flexible Duct. If the quote could be read as either, add the line that separates them: the rating, the fitment, or the standard named below. Link the drawing number to that line so receiving inspection can reject the wrong one.

Numbers that change the quote

Line What to write for Expansion Valve
Capacity Cooling or heating at the outdoor and indoor condition, not only a nominal ton.
Air or water Airflow or water flow and the pressure drop.
Electrical Voltage, phases, and the starting method.
Refrigerant or fuel The fluid, as the market allows. Handling it is a licensed job, not a note on this page.
Installation Split, packaged, or a terminal unit, and the clearance.
Noise The sound figure at a stated distance.

How to compare two offers

Lay both quotes for Expansion Valve on one sheet and line up capacity, air or water, and electrical. If a cell is empty, the offer is not finished. Ask for the missing line in writing. When those match, the honest difference is lead time, the test evidence, and who carries the warranty. Do not average a fully specified Expansion Valve with a cheaper line that omitted capacity.

Documents worth having before the deposit

Ask for the capacity at the design outdoor temperature. The file should name Expansion Valve and the revision, not only the supplier’s homepage. A factory quality certificate such as ISO 9001 can sit beside that file. It does not replace it.

Failures that show up after delivery

  • Treating refrigerant work as a purchasing checkbox.
  • Buying nominal tons and discovering the derate on a hot day.
  • Ignoring duct or pipe pressure drop.

On an Expansion Valve, the expensive version of the first mistake is discovering it after the goods are in the crate. Put the rejection condition in the purchase order while the supplier can still restate the offer.

A worked RFQ line

Use this shape, then replace the brackets with your duty: “Expansion Valve — State capacity at a condition, airflow or water flow, electrical supply, and noise.” That sentence is a template, not a rating of any brand. If a supplier’s datasheet uses different units, convert them onto this sheet so the next offer can be compared.

Where words like stainless / corrosion belong

Searches often add a constraint to Expansion Valve: stainless / corrosion, or explosion-proof / ATEX. Keep those on this page. Name the alloy or the coating and the chemical it must survive. Stainless is a family, not a guarantee. ATEX or IECEx is a certificate for a zone, a gas or dust group, and a temperature class. An IP rating does not grant it. Skip the mark if the site is not hazardous. If you need a third constraint, add it as another line on the same drawing. A second URL that only swaps the adjective does not give a buyer a second fact.

Related in this section: how to specify Flexible Duct.

Questions buyers actually ask

What should an RFQ for Expansion Valve include?

State capacity at a condition, airflow or water flow, electrical supply, and noise.

Is a cheaper Expansion Valve the same part?

Only if capacity, air or water, and the documents match. A missing line is a different offer.

Do waterproof, OEM, or IP words need their own page?

No. For Expansion Valve they are extra lines on this specification. Ask for the test or the drawing that gives the word a value.