The Castair 3BG is the OEM steel belt guard designed specifically for Castair C1, D3, and G11 air compressors. If your shop runs any of those models and the original guard is cracked, missing, or damaged, this is the part you need — not a generic aftermarket cover that almost fits, but the factory-matched replacement that bolts on correctly and meets the safety requirements your shop is responsible for. Dimensions are 32 x 20 x 5 inches, matching the belt and pulley geometry of the C1, D3, and G11 compressor frames exactly.
Safety and Compliance
- OSHA 29 CFR 1910.219 requirement: Federal regulations require that all exposed rotating parts — including belts, pulleys, and drive shafts on air compressors — be guarded at all times during operation. An open or damaged belt guard is a recordable citation waiting to happen.
- Why the OEM guard matters: Aftermarket belt guards are often sized for "close enough" fit. On a Castair C1, D3, or G11, close enough is not good enough. A guard that doesn't seat flush leaves gaps that fingers, rags, and debris can reach. The OEM 3BG is engineered to the exact frame tolerances of these models.
- Insurance implications: Most shop liability policies require that equipment be operated with all factory safety components in place. Running a compressor with a missing or improvised guard can void coverage on a belt-related injury claim. Document your parts replacements — an OEM part number on an invoice is evidence of compliance.
- Employee safety: Belt drives on reciprocating compressors run at high RPM. An exposed V-belt will catch loose clothing or gloves instantly. The 3BG eliminates that exposure entirely when properly installed.
Construction and Specifications
- Frame material: Steel — welded and formed, not plastic or pressed sheet. Steel guards hold their shape when bumped by carts or equipment, and they don't crack from UV or temperature cycling in an unheated shop.
- Dimensions: 32 inches wide x 20 inches tall x 5 inches deep. These measurements correspond directly to the belt and pulley stack depth on Castair C1, D3, and G11 units. Do not attempt to substitute a guard with different depth — the 5-inch depth is specific to the drive geometry on these models.
- Finish: Protective coating to resist shop environment corrosion — oil mist, moisture, and cleaning chemicals are all present in a working compressor bay.
- Mounting points: OEM bolt pattern matches the C1, D3, and G11 frames. No drilling, slotting, or fabrication required.
Model Compatibility
- Castair C1: Single-stage reciprocating compressor. The 3BG fits the belt drive assembly on this model directly.
- Castair D3: The 3BG covers the D3 belt and pulley configuration. Verify your D3 is the belt-drive variant — direct-drive D3 units do not use this guard.
- Castair G11: The G11 shares the same belt guard mounting geometry. The 3BG is the correct replacement for this model.
- Ordering the right part: Belt guards are not interchangeable across compressor families. The C3 and G30 use the 4BG7 (40x20x7). The C2 uses the 4BG (40x20x5). If you are not certain of your model, check the nameplate before ordering — it is on the crankcase, typically near the oil fill port.
Installation
- De-energize first: Lock out and tag out the compressor before removing or installing any belt guard. This is not optional — it is the law and basic sense.
- Bolt-on replacement: The 3BG mounts to the existing frame holes on the C1, D3, and G11. Remove the fasteners from the old guard, position the 3BG, and reinstall. No modification required on the correct model.
- Inspect before installing: While the guard is off, inspect the belt for cracks, glazing, or fraying. If the belt shows wear, replace it now — you already have the guard off and the compressor locked out.
- Torque fasteners properly: Do not overtighten. The guard is steel but the mounting tabs are not designed to be stressed by over-torqued hardware. Snug and secure is correct.
- Wrong model = wrong guard: If the bolt pattern does not align, stop. You have either the wrong guard or the wrong model identified. Call us before drilling new holes — 866-217-0063.
Why Buy From Air Compressor Factory Direct?
- OEM parts only: We stock genuine Castair replacement parts, not knockoffs or generic substitutes. The 3BG you receive is the same guard Castair ships with new C1, D3, and G11 units.
- Specialist since 2016: Air compressor parts is all we do. We know the Castair line and can confirm compatibility before you order.
- Free shipping: No handling fees, no freight surcharges on standard orders.
- Free technical support: Call 866-217-0063 and talk to someone who knows Castair compressors. If you are not sure whether you need the 3BG, 4BG, or 4BG7, we will help you identify the correct part from your model number.
- Full manufacturer warranty: OEM parts come with manufacturer warranty coverage. Aftermarket substitutes typically do not.
Call 866-217-0063 for quick answers and help!
