My positive rating is for the stainless version I ended up using (RS15-6SB). I had initially purchased a non-stainless version of the same pump under a different "brand" (KolerFlo) and the issues I had are summarized below but I'm 99% sure the issues with that one would also apply to this BokyWox line so I'm including my review for people to hopefully learn from.TLDR: The non-stainless version WILL rust; try different versions (and different "brands") of this pump if yours doesn't seem to pump…

use hose /npt adapers on each end. Double up on hose washers on each end [4]and it will seal just fine and not leak. Requires electricity to operate making it less efficient during power outages.

Used this in conjunction with a bypass for my bathroom and kitchen sinks, to have hot water at the faucet, and not waste water down the drain.

This was very easy to install and we no longer have to waste gallons and gallons of water before the hot water arrives at the tap. Very happy with this purchase.

Purchased for a hot water recirculation line between master bath and water heater to have instant hot water at sink and shower. Used copper O-ring fitting flex lines to attach to pump and adapt to Poly pipe. NPT threads are not reliable to use and not leak. Major gripe is that there is no place to attach any mounts/brackets/etc. to suspend/mount this under a floor in basement. The only was is to use the pipe as support, mainly at the water heater fill pipe. Due to the nature of how the tank was

I used this to create a heater core flushing system using CLR and Water in a large pot with a suction hose and a return hose. The heater was only producing heat at about 90 degrees but after the flush it's back at over 130 degrees in all fan speeds. This saved me a heater core replacement bill of over $1000.00 !

Disappointed that this could not be used with my tankless water heater to recirculate. Even with many wraps of Teflon tape, it still leaked.

Using this pump to circulate domestic hot water so distant faucets have near-immediate hot water. Pump works great and is quiet running.However.the product description for this pump says "can be used in drinking water pipelines", and then says "not suitable for potable water". Which is it? For the model I bought (cast iron pump housing), it may be the latter. Even after the "3-5 times of use" there is still a taste in the water of chemical, where there wasn't any before the pump was installed…

Added this pump, a bridge valve under kitchen sink and master bathroom sink. Plugged this pump into a "smart” plug which is fully automated to now provide "instant endless” hot water from my new electric tankless hot water heater.

It was difficult to secure a leak free attachment to the copper piping. A dielectric fitting finally worked; with copious amounts of pipe tape. I have the pump plugged into a smart plug which runs it for 3 minutes when i state ' hot water' with Alexa. The pump works great, saves water.

First one worked for two years exactly running 24/7. Replaced it with this same model because of size and convenience. Hoping this one will last longer because I have it on a timer programmer.