Circulator pump

The ALPHA2 is the circulator I’d put on a boiler zone today, and I’ve used it. Grundfos calls the ALPHA2 15-55 a high-efficiency ECM variable-speed circulator for heating and hot-water recirculation, with AUTOADAPT and constant-pressure control modes.

AUTOADAPT is the point. Instead of you picking speed 1, 2 or 3, the pump adjusts itself to the system. Grundfos’s submittal for the 15-55F lists power input of 5 to 45 watts.

The same sheet lists a maximum head of 18.05 feet, a maximum operating pressure of 145.04 psi, a liquid range of 35.6 to 230°F, a cast iron housing, a composite impeller and a port-to-port length of 6½ inches. Net weight is 7.06 pounds.

This listing is the /LC version, which adds a line cord, so you can plug it in where the old pump was wired to a cord. Grundfos lists it as its own product, 99163906.

Where it lost points: Grundfos doesn’t list a built-in check valve for this model, which scored 7. On a zoned system with more than one pump, add an in-line flow check so a running zone can’t push water backward through this one.

One listing note: the Amazon photo shows a brass-colored pump body. Grundfos lists this model’s housing as cast iron, and so does the listing title.

It was down to 10 left when I checked. The price line shows the current seller.

My reading: an 18-foot head is plenty for a short baseboard zone, and because AUTOADAPT slows the pump when the zone needs less flow, it can spend much of the heating season near the low end of its 5 to 45 watts.

My call: on a single-zone boiler, or zones run by zone valves with one pump, the ALPHA2 is the easiest upgrade here. Set it, wire it, and let it pick its speed.

The Astro 230Ci is the 3-speed pump I’d stock on a service truck, and I’ve used it. Armstrong’s Astro 2 submittal lists it as a cast iron, flanged, three-speed circulator with a removable check valve installed at the pump outlet.

Armstrong rates the Astro 2 line at 150 psi maximum working pressure and 230°F maximum fluid temperature for this model. It’s ETL listed for the US and Canada to UL 778 and CSA C22.2 No. 108.

The motor table gives the Astro 230 a full-load draw of 0.45, 0.58 and 0.81 amps on speeds 1, 2 and 3, and 97 watts nominal. The cast iron 230Ci weighs 8.0 pounds.

Armstrong’s cross-reference chart is why I like it for replacements. It lists the Astro 230 on speed 1 against the B&G NRF-9F/LW and Taco 005-F2, on speed 2 against the Taco 007-F5 and 007-F5-7-IFC, and on speed 3 against the B&G NRF-22.

Where it lost points: three set speeds scored 8 against the ALPHA2’s automatic control, and 97 watts nominal scored 7.

Armstrong lists cast iron bodies for closed systems and stainless steel for open systems. This cast iron pump is for boiler loops, not domestic hot water.

Armstrong also sells a 230Ci-R with a rotated flange. This listing is the standard 110223-305.

On a multi-zone boiler with a pump per zone, the outlet check valve is what keeps a running zone from pushing water backward through this one, so you don’t need a separate flow check on the piping. Armstrong rates the cast iron Astro 2 bodies for closed boiler loops, and this one weighs 8 pounds, so support the piping on both sides of the flanges.

My call: start on speed 2 when it replaces a Taco 007, and only move up if the far end of the zone stays cool.

Grundfos calls the UPS15-58FC its “Super Brute” and says it replaces over a dozen competing models from a truck’s stock. It’s the pump I’d grab when I don’t know what’s on the wall, and I’ve used it.

The Grundfos sheet lists three speeds drawing 60, 80 and 89 watts at 0.55, 0.66 and 0.75 amps, a flow range of 0 to 17 gpm, a head range of 0 to 19 feet, and 145 psi maximum operating pressure.

Its check valve is removable and built into the pump. Grundfos says it improves zone-valve close-off, prevents thermosiphoning, allows minimal system flow and saves the cost of an in-line check valve.

The sheet’s cross-reference lists B&G NRF-22 and NRF-9F/LW, Taco 005, 007, 008 and 007 IFC, and Armstrong Astro 30 among the pumps it replaces.

Where it lost points: Grundfos rates the pump to 230°F, but notes a 200°F maximum with the check valve fitted, which scored 8. Three set speeds scored 8, and its 89-watt top speed scored 8.

The sheet also lists minimum inlet pressures: 15.6 psi at 230°F, 4.0 psi at 190°F and 1.3 psi at 140°F. My call: many residential boilers are filled to about 12 psi, so watch the water temperature on this pump.

It weighs 7¼ pounds and uses a 2-bolt flange with ½-inch bolt holes. The listing title calls it red.

Grundfos adds that the pump has a ceramic shaft and radial bearings, a carbon thrust bearing and a stainless rotor can, lubricated by the boiler water itself, so there’s no shaft seal to leak or oil to add.

My call: on a boiler that runs hotter than 200°F, pull the check valve and fit an in-line flow check instead, or choose the Armstrong.

The 007 is the pump most of us find on the wall of an older boiler, and this IFC version is what I’d put back. I’ve used it. Taco’s 007-IFC catalog describes a cast iron cartridge circulator with a removable integral flow check.

Taco says the spring-loaded IFC replaces a separate in-line flow check, protects against reverse flow and gravity flow, and has a lower pressure drop than an in-line check. Both the IFC and the cartridge come out for service.

The catalog lists the 007-F5-7 IFC at 1/25 horsepower, 115 volts, 0.71 amps and 3,250 rpm, with a permanent split capacitor motor. Taco lists a flow range of 0 to 17 gpm and a head of up to 8.5 feet for the IFC model.

Taco rates it from 40 to 230°F and 125 psi maximum working pressure, with 3/4- to 1½-inch flanges. Shipping weight is 9 pounds.

Where it lost points: one speed scored 7; 125 psi, the lowest rating here, scored 7; and Taco publishes amps rather than watts, which scored 7.

Taco names applications for it: hydronic heating and cooling, hydro-air fan coils, radiant and indirect water heaters. It reserves domestic water recirculation for the stainless steel 007-SF5-7 IFC.

The listing also lists Taco’s service parts: cartridge 007-042RP, flange gasket set 007-007RP and capacitor 007-002RP.

Taco lists the materials: a stainless steel cartridge, ceramic shaft, carbon bearings, a non-metallic impeller and EPDM O-rings, with an acetal flow check body and a stainless spring. It’s self-lubricating with no mechanical seal, so on a boiler zone it needs no oiling.

My call: if the old 007 failed on a cartridge, the 007-042RP cartridge alone may be the fix. Replace the whole pump when the body is rusted or the flanges are seized.