Barnes & Jones Drop-In Steam Trap Cage Units, Armstrong, Spirax Sarco, Hoffman & Ventrite
Stop live steam blow-through and water hammer in New England schools, hospitals, churches, and historic mill buildings. We cross-reference over 1,500 active and obsolete radiator trap models to drop-in Barnes & Jones cage units.
Why New England Facility Engineers Retrofit with Drop-In Cage Units
In older steam-heated buildings across Massachusetts and New Hampshire, attempting to wrench an original 1930s–1970s brass trap body or tailpiece out of a cast-iron radiator or rusted condensate return drop often shears the nipple—turning a 10-minute maintenance task into an expensive pipefitting repair. Even worse, replacing only the bellows without replacing the eroded brass seat inside the trap body allows live steam to keep blowing past the plug.
A Barnes & Jones Cage Unit solves both problems simultaneously: it combines a brand-new, factory-calibrated phosphor-bronze or stainless-steel thermostatic bellows AND its own matched stainless-steel valve seat inside a single drop-in cartridge. Simply unscrew the trap cap, lift out the old element, drop in the exact B&J Cage Unit, and tighten the cap. Our Lowell counter at 149 Congress Street identifies unmarked traps by cap thread OD, body depth, and seat bore.
Need Immediate Part Verification?
Bring your sample component or email a clear nameplate photo to our 149 Congress Street counter team for same-day pickup or regional truck delivery.
Thermostatic Radiator Trap & Drop-In Cage Unit Cross-Reference Matrix
Bring your trap cap and internal element to 149 Congress St for caliper verification against our master Barnes & Jones gauge board.
| Original Trap Manufacturer | Legacy Model Numbers | Pipe Size | Operating Pressure | Barnes & Jones Drop-In Solution | Seat Renewal Method |
|---|---|---|---|---|---|
| ITT Hoffman Specialty | No. 17C, 17D, No. 8, No. 8C, No. 9, No. 9C | 1/2", 3/4", 1" | 0–15 PSIG (17C) / 0–25 or 50 PSIG (#8/#9) | Exact B&J Cage Unit or Genuine Hoffman Thermal Element | Integral stainless seat in B&J cage (no seat wrench needed) |
| Dunham-Bush / C.A. Dunham | No. 1E, 1A, 1B, 1C, TH1A, TH2, 71A, 72 | 1/2", 3/4" | 0–15 PSIG / 0–25 PSIG | B&J Calibrated Cage Unit matched to Dunham body depth | Seals directly against gasketed body shoulder |
| Warren Webster & Co. | 02H, 502, 512, 513, 702H, 712, 722, Sylphon | 1/2", 3/4", 1" | 0–15 PSIG (Low-Pressure Steam / Vacuum) | B&J Drop-In Cage Unit for Flat or Bevel Seat Webster bodies | Replaces both bellows and worn pressed-in seat |
| Spirax Sarco | Type H, Type T, TB-9, TD-52 (Thermodynamic) | 1/2", 3/4", 1" | 0–25 PSIG / 0–65 PSIG / up to 600 PSIG (TD-52) | B&J Cage Unit or Genuine Spirax Sarco Bellows / Disc Assembly | Complete internal capsule & seat assembly |
| Marsh / Trane / Illinois | Marsh #1/#2, Trane B1/B2/B3, Illinois Series G/1G | 1/2", 3/4", 1" | 0–15 PSIG / 0–25 PSIG | Custom B&J Cage Unit stocked/sourced via Lowell Steam Desk | Zero re-piping; preserves historic radiator unions |
Main Drip, Heat Exchanger & Process Steam Trap Engineering Matrix
Selecting the correct trap technology for steam mains, unit heaters, domestic hot water convertors, and hospital sterilizers.
| Trap Technology | Stocked OEM Series | Condensate Discharge Profile | Air Venting Capability | Best Boiler / Plant Application |
|---|---|---|---|---|
| Float & Thermostatic (F&T) | Spirax Sarco FT-15 / FT-30 / FTI, Hoffman FT, Armstrong A/B Series | Continuous modulation at steam temperature | Excellent (built-in balanced-pressure thermostatic air vent) | Modine/Beacon-Morris unit heaters, fin-tube zones, air handling coils & shell-and-tube convertors |
| Inverted Bucket | Armstrong 800, 811, 812, 813 (Cast Iron) & 2010/2011 (Stainless) | Intermittent discharge at steam temperature | Moderate (bleed hole in bucket top) | High-pressure steam main drips, laundry presses, industrial process headers & superheated lines |
| Thermodynamic (Disc) | Spirax Sarco TD-52 / TD-42, Armstrong CD | Intermittent blast discharge | Fair (requires separate air vent on startup) | Outdoor steam tracing, high-pressure mains & freeze-exposed drip legs |
| One-Pipe Steam Air Vents | Ventrite #1 (Non-Adj), #11 (Adj), #33/#35 (Vacuum), Hoffman #1A, #40, #75, #79 | Vents air only; float closes against water & thermostatic float closes on steam | High-capacity air elimination | Balancing cast-iron radiators and venting long steam mains (#75/#79) so distant rooms heat evenly |
5-Point Counter Identification Checklist for Any Steam Trap
- 1. Manufacturer Name & Model Number stamped on the hex cap or cast into the side of the brass/iron body.
- 2. Nominal Inlet/Outlet Pipe Size (1/2", 3/4", 1", 1-1/4", 1-1/2", 2") and body pattern (Angle, Straightway, Vertical, or Right/Left Offset).
- 3. System Operating Steam Pressure in PSIG (critical for Inverted Bucket and F&T traps: a 15 PSI orifice cannot open against 60 PSI differential pressure!).
- 4. For unmarked radiator traps: Bring the old cap and element to 149 Congress Street so we can measure cap thread OD, threads-per-inch, cap-to-seat depth, and seat bore diameter.
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Counter Q&A: Steam Traps, Barnes & Jones Cage Units & Ventrite
Why does installing a 125 PSI Float & Thermostatic trap on a 5 PSI steam heating coil starve the coil of heat?
F&T and Inverted Bucket traps use a fixed discharge orifice sized for a specific maximum differential pressure (such as 15 PSI, 30 PSI, 75 PSI, or 125 PSI). To allow the float to pull the valve open against 125 PSI, the orifice must be much smaller than on a 15 PSI trap—drastically reducing condensate capacity at low pressures and waterlogging the heating coil.
What is the difference between a Ventrite #1 and a Ventrite #35 radiator vent?
Made right here in Massachusetts, the Ventrite #1 is a standard non-adjustable low-pressure radiator vent, while the #11 features a bottom dial with 8 venting rates to balance fast- and slow-heating rooms. The #33 and #35 add a check diaphragm to create a thermal vacuum as the boiler cycles off, holding heat in the radiators longer.
Can you test or identify an unmarked brass radiator trap from a 1920s school or church?
Yes. Bring the complete brass trap body or the cap and internal element to our Plumbing & Steam Counter at 149 Congress Street, Lowell (978-454-7606). We match unmarked traps against physical Barnes & Jones sizing templates every day during heating season.
Request a Counter Quote or Cross-Reference: Steam Traps, Barnes & Jones Cage Units & Ventrite
Routed directly to our 149 Congress Street, Lowell specialists. Eligible for COMMBUYS FAC124 (#201354) and MHEC G14 (#374) / G19 (#419) purchasing.