Armstrong 800–813 Inverted Bucket Steam Traps

Cast-iron horizontal inverted-bucket steam traps with free-floating stainless mechanism, continuous air/CO₂ venting, and capacities to 4,400 lb/hr.

Key advantages

Repairable cast-iron package — ASTM A48 Class 30 body; 304 SS internals; 17-4PH valve/seat.
To 250 psig class — MAP 250 psig @ 450 °F; Model 800 MOP 150 psig; 811–813 MOP 250 psig.
Capacities — 800: 700; 811: 1,050; 812: 2,200; 813: 4,400 lb/hr.
Water-hammer resistant — top orifice, water seal, continuous venting at steam temperature.

Typical applications

Condensate drainage on steam-using equipment needing side-inlet/side-outlet horizontal traps.
Systems specifying screwed NPT or BSPT connections from ½…1 in. by model.
Sites wanting optional internal check valve, thermic vent bucket, or pop drain.

Selection guide

800 — 700 lb/hr; MOP 150 psig; connections ½ / ¾ in.
811 — 1,050 lb/hr; MOP 250 psig; ½ / ¾ / 1 in.
812 — 2,200 lb/hr; MOP 250 psig; ½ / ¾ in.
813 — 4,400 lb/hr; MOP 250 psig; ¾ / 1 in.
MAP — 250 psig @ 450 °F (17 bar @ 232 °C) vessel design.
Options — CV internal check; T thermic vent bucket; pop drain; probe; thermo drain; scrub wire.
Order data — model, connection size/type, max working pressure or orifice, options.

Common mistakes

Ordering 800 for >150 psig service — use 811–813 for 250 psig MOP.
Undersizing capacity — match lb/hr and differential pressure, not just pipe size.
Specifying both thermic vent and check on 800 when OEM notes that combination is not available.
Steam & condensate

When to RFQ / what to tell us

Model (800/811/812/813) or capacity/pressure target.
Connection size and NPT vs BSPT; orifice / max working pressure.
Options (CV, thermic vent, etc.); quantity; ship-to.

Request a Quote · Get selection help

Specs

Spec	Value
SKU	252579
Brand	Armstrong International
Model	800 / 811 / 812 / 813
Product type	inverted bucket steam trap
Body material	Cast iron ASTM A48 Class 30; internals 304 SS; valve/seat 17-4PH
Max allowable pressure	250 psig @ 450 °F (17 bar @ 232 °C)
Max operating pressure	800: 150 psig; 811–813: 250 psig
Capacity	700 / 1,050 / 2,200 / 4,400 lb/hr by model
Process connection	Screwed NPT and BSPT (½–1 in. by model)
Notes	Specs from Armstrong Series 800 product page and DataSeries800813 PDF.

Documents

Armstrong 800–813 inverted bucket data sheet (PDF)

FAQ

Q: 800 vs 811 — which for 200 psig? A: Model 800 MOP is 150 psig; use 811–813 for 250 psig MOP class.

Q: Are these repairable? A: Yes — OEM states all Armstrong cast-iron inverted bucket traps are repairable.

Q: What should I send for a quote? A: Model, connection, P/T, capacity, options, quantity. Compatible with systems using Armstrong 800-series if you need a drop-in check — we do not claim authorized-dealer status.