To start, pumps are not rated in horse power, motors are. The motor that runs this pump is 1/25 of a horse power. You can have two pumps, both using the same motor, but they can have vastly different performance. This is because pump performance is determined by the size and shape of the impeller as well as the volute or chamber in which the impeller spins. Pump performance is illustrated on a graph called a pump curve. On one axis you have height and on the other flow rate, the graph illustrates pump performance at all these points. Now I assume you are confused because the motor seems very small to you. That is because this is a particular type of pump, called a circulator. Circulators are used in pressurized systems. They do not fight gravity like a sump pump does. One PSI lifts water 2.3'. So lets say this pump is used in a closed loop heating system that is pressurized to 15 PSI. The internal system pressure can lift the water 34.5 feet vertically. The system pressure acts much like the counter weight on an elevator and cancels out the force of gravity. Circulators only job is create a pressure drop. This pressure drop creates flow in the closed loop heating zone. This may cause you to ask, then why are the three speeds and why are there so many different circulators. This is because in each heating system is unique and designed. You want a specific volume of water to move at a specific speed. This insures that the "Delta T" the change in water temperature meets design parameters. It the temperature drop is too high, the system efficiency can go to high causing the boiler to condense and become damaged. To low and efficiency can drop to unacceptable levels. Chris 978 651 3301
Yes. In fact you can see it in the picture. The flow check is that white piece you see in the center of the top flange.
When the listing speaks of including " 2 gaskets for sealing" it is referring to flange gaskets. Personally I don't like the gaskets Grundfos and Taco include with the pumps. So I use full face gaskets which I buy separately. They are Home Depot SKU 202277432. If you put that number in the search block it they will come up.
I may be reading too much into your question but the way its worded makes me think you may envision this product as some type of “turbo charger”. As in a devise that is going to speed up the flow of water. That is not the case. Neither with this particular unit or any of the other brands or models. Your water is going to move at a rate determined by the water pressure, the pipe size and the flow rate of your source. Recirculation are very small pumps that periodically create flow when water is not being consumed so that there is hot water at the furthest point in the system. This way there is hot water at the fixture in case you happen to need hot water. Now let’s bring in the tankless water heater variable. Some tankless water heaters can be use with recirculation other can’t; recirculation either won’t create enough flow to turn the heater on, and others will fail prematurely due to the short cycling resulting from the frequent short cycles caused by the recirculation pump. First you want to determine if your heater was designed to work with recirculation. If it is great. If not there are ways of getting around this. Giving you the ability to have recirculation with a tankless heater not designed for it. One is to put a small electric tank type heater in front of the tankless unit and recirculate that. In this configuration you cycle the stored hot water to insure hot water in the pipe at all times, then when a substantial draw takes place the tankless will take over. I would advise you have a qualified licensed contractor take a look at your specific installation take a look at your installation.
Great question. The cast iron residential flanges that use two bolts on each flange are pretty much standardized. So if I am replacing a B&G pump with a Taco, Grundfos, Aqua Motion etc. I do not change the flanges. Also the distance from the face of one flange to the face of the other flange has been pretty much standardized sense 1970. So the only time you end up doing any piping is if it is a real old pump or larger commercial pumps.
That would depend on the total dynamic head. As such the answer is not fixed but shown on a curve for all three speeds. My apolozies for not having it on the product listing page. I will now add it but that may take a while to up load. If you would like to call me I can email it to you. Chris 978 651 3301
Grundfos does not publish torques settings for flanges on hydronic heating systems. Neither does Taco or B&G for that matter. Reason being a hydronic heating system is only under 15 PSI there fore it is just not critical. Circualter flanges just do not need to be that tight. However the big mistakes people make are they over tighten one side and then move on to the other. This can pinch the gasket. Then no matter how tight you make them you will have a leak path. Best practice is as follows. Hand tighten one side them the other. Continue to go back in fourth between the two sides bringing the faces of the flanges together evenly.
I would need more specific information about the pump you are replacing so that I could look up its pump curve. If you would like to give me a call we can discuss your need. Chris 978 651 3301