GrundfosV4-53SB-MZAB 115V Grundfos Circulating Barb Pump

I have a 20 year old hot tub that I continue to nurse and it keeps running. The circulating pump in this unit runs 24/7. Over the years I have replaced the circulating pump about 4 time. This time I decided to try the Grundfos pump vs the Waterway Tiny Might I have used over the years. I really like this pump!! It has better GPM and is sooooo quiet compared to the Waterway. I am hoping it's longevity matches my expectations. If so, this is my new replacement unit. Oh, and the price is much better too!

Works well, barbs are 1 inch instead of 3/4 so need to use an adapter for my Whirlpool. Moving pump outlet location is easy on the pump. The electrical wiring is easy to connect but is not water tight. You will need to use a rubber grommet or electrical tape to seal with rubber caulk. Doing the rewire yourself will save you some money but takes some time to do it properly.

I purchased this circulation pump for my very old Hot Spring spa. I first purchased an E5 direct replacement pump that was more money and only lasted a few months. I found this pump that was highly recommended by "YouTuber spa fix-it guys" and bought it. It is much "beefier" that the E5. Seems a lot more rugged. My only complaint was that the hose fittings were larger on this pump than on the original E5. This required an adapter. Back to YouTube and got that figured out in a matter of minutes. It has been working like a champ now for about 3 months. Runs stronger. Whisper quite. I think I have my circulation spa pump handled for years to come.

Went out this morning and the overheat protection light was on. Unplugged Spa to reset, plugged in and no luck. Dead circulating pump. Sad for a supposedly US manufactured product. Was satisfied with the ease of installation, and the quietness of the motor. Price was right and felt of good quality. Unfortunately lasted only 2 weeks and was not willing to take another chance on anther - once bitten twice shy. From the looks of all other circulating pumps available, it is truly a crap shoot.Also to note (second pic): This pump had a small piece of plastic broken off of the flange when received. The small broken piece was not in the box, so must have happened elsewhere. It didn't effect anything, so I kept and installed. It is plausible that this motor was dropped elsewhere, causing the short performance period.

The pump arrived on time, was simple to install and has performed as expected in my 300 gal spa. No surprises and no issues. Since I still had the old pump I was replacing, it was a straight forward process to remove the power cord from the old pump and reattach it to the new pump. The pump comes with a mounting plate that can be attached in one of several locations around the circumference, thus allowing you to orient the pump inlet and outlet as needed. It comes with a mounting plate that is plastic, which from my point of view is fine as the old pump's mounting plate was metal and very corroded.

it is a good solid quite running pump, I had issues because my hoses are 3/4" and these fittings are 1" so I had to get fittings to reduce my hoses down. Just wish Grundfos made this same pump in 3/4" size.

This was the best I found to replace my seized heater circulating pump. I had to wire the old cord to it for the proper plug and adapt the hose sizes. It is very quiet and does the job. Hopefully bought a few more years on a older tub that has no parts support anymore.

Pump is working fine...so far. It runs very hot to the touch. I was not aware this would be the case. A message in the instruction manual this would happen would have been nice. Seems like a simple thing to do.