A suction guide is one of the simplest ways to save space and money in a pump room – yet it's often left off drawings or specified incorrectly. Here's what it does, when to use one, and how to pick between the five Armstrong suction guide series we stock.
In this guide
What is a suction guide?
A suction guide bolts directly to the suction side of a centrifugal pump. In one fitting it does three jobs: it turns the flow 90°, straightens it with internal guide vanes, and strains out debris with a removable stainless steel strainer.
Without one, you'd typically need a long-radius elbow, a separate strainer and a straight run of pipe ahead of the pump so the water enters the impeller smoothly. The suction guide replaces all three.
Why use one?
- Saves floor space – no long straight pipe run before the pump.
- Fewer fittings and joints – faster installation, fewer leak points.
- Protects the pump – the strainer catches scale, weld slag and debris, and a fine-mesh start-up strainer catches construction debris during commissioning.
- Easy maintenance – the strainer comes out through the cover without disturbing the piping.
The five Armstrong series compared
| Series | Connections | Rating | Sizes | Best for |
|---|---|---|---|---|
| SG | ANSI 125 flanged | 175 psi, 300°F | 2" x 2" to 14" x 12" | Most HVAC and plumbing systems |
| SGG | Grooved inlet, ANSI 125 flanged outlet | 175 psi, 300°F | 2" x 2" to 14" x 12" | Grooved piping systems (Victaulic, Anvil) |
| SGHH | ANSI 250 flanged | 375 psi, 300°F | 2" x 2" to 14" x 12" | High-pressure systems, tall buildings |
| SG Threaded | NPT inlet, ANSI 125 or 250 flanged outlet | Up to 375 psig at 150°F | 1-1/2" and 2" inlets | Small pumps and light commercial |
| SG ANSI 150 | ANSI 150 flanged, carbon steel | 175 psig, 300°F | 14" x 14" to 24" x 20" | Large chillers, plants, district systems |
How to choose
- Match the pump suction size – the outlet of the suction guide bolts to the pump suction flange. Model numbers follow inlet x outlet: an SG-43 has a 4" inlet and 3" outlet.
- Match your piping – flanged, grooved or threaded on the system side.
- Check the pressure class – ANSI 125 covers most buildings; go to SGHH (ANSI 250) when system pressure is higher.
- Leave withdrawal clearance – every model lists a "G" dimension: the space needed to pull the strainer out. Don't box it in against a wall.
- Plan the support – suction guides are supported from below with a pipe support sized to the "H" dimension.
From the shop: The most common mistake we see is forgetting to remove the fine-mesh start-up strainer after commissioning. It clogs quickly, starves the pump and causes cavitation. Mark it on the start-up checklist.
FAQ
Do I still need a strainer if I install a suction guide?
No – the strainer is built in. That's one of the main reasons to use one.
Can a suction guide be used on a fire pump?
Fire pump suction piping is governed by NFPA 20, which restricts devices on the suction side. Check with the fire protection designer – see our fire pump guide.
Are Armstrong suction guides only for Armstrong pumps?
No. They bolt to any pump with a matching ANSI flange, including Bell & Gossett base-mounted pumps.
Related reading
Shop Armstrong suction guides
Browse all five series with full dimensions, drawings and submittals in our Armstrong suction guides category, or ask us to size one for your pump. Call (416) 236-2338 or email sales@bramhambros.com.