Constant Pressure pumps

I'm looking at putting in a Grundfos constant pressure pump and controller. Does anyone have any experience with these? It only has a 2 gallon pressure tank with it, which seemed a little odd, but the literature sounds convincing.

It'd be nice to have consistant water pressure and not take up the room in the basement with a big tank.

John

bonzai95 said:

I'm looking at putting in a Grundfos constant pressure pump and controller. Does anyone have any experience with these? It only has a 2 gallon pressure tank with it, which seemed a little odd, but the literature sounds convincing.

It'd be nice to have consistant water pressure and not take up the room in the basement with a big tank.

Click to expand...

It doesn't need a large pressure tank since it is adjusting for demand. What does the literature say about additional energy costs, how does it compare to the CSV? It would eliminate the high back pressure that the valve creates.

Rancher

Well, there are two parts to the system; the pump and the controller. Here are some links, but I don't think they say anything about efficiency.

http://www.envisupply.com/environmental/Grundfos/residential_well_pump.htm

http://www.envisupply.com/environmental/Grundfos/SmartFlo.htm

"Grundfos Kaput"

https://terrylove.com/forums/showthread.php?t=13133

Here is a link to some more info.

Sorry I missed this one. I have been out of town. As far as I am concerned, the Grundfos SQE is the best of the variable speed systems available. However, the CSV will duplicate the performance of the constant pressure pump while water is being used, and will give you the benefit of being able to use water from a small tank during short term water uses. Variable speed pumps are not able to use water from any tank. Therefore, the pump must start every time the ice maker comes on or you wash a toothbrush. Here are a couple of links that may help explain.

http://www.cyclestopvalves.com/comparisons_12.html

www.cyclestopvalves.com/video/commercial-dsl.wmv

we have installed three types. we installed one or two the goulds. they did not work well.

next we have installed some grundfos. they are simple, but not any more simple then the others. they work well. the bad thing about the grundfos is that they use a small three inch pump that operates at up to 12000 rpm. it concerns me a bit to have anything run that fast. i would prefer a pump that ran at 1200 rpm.

we have install a lot of franklin units. up until recently the franklin sub or mono drive was just the controller and you used someone else's pump. now franklin make their own pump. we still use the goulds pump. we just haven't gotten into jacuzzi pumps yet. at least i think that is jacuzzi that franklin bough out. these units are just as simple as the grundfos even if they don't have the childlike installation drawings. i also like the mono drive in this family better because you could in install a standard control box and pressure switch if you local guy doesn't have a mono drive on hand and yours fails.

I have heard there are problems with using a larger tank with the SQE. Something about them not being able to fill the tank and shut off. Even with a larger tank, a 1.5 PSI drop in pressure turns on the pump, so the pump will still need to start just to fill the ice maker. Also I believe they actually spin about 10,600 RPM which is still much faster than the normal 3450. According to Grundfos' own engineering manual, every time you double the RPM, you quadruple the wear rate.

I have also heard of lots of problems in the field with the Goulds Balance flow system. The Franklin Mono drive will work with a normal single phase pump but, also has many problems. The Franklin uses a go/no go switch instead of a pressure transducer. This means the pump is continuously bounced on and off 45 time per minute to try and maintain a set pressure. That would be a million switches every 21 days when using less flow than the maximum capable by the pump. The biggest problem I am hearing about this, is that the torque of starting the motor 45 times per minute is quickly wearing out the wire in the well. Also hearing about major problems with stray voltage and nuisance trips with these units.

We used Variable Speed Controllers of several different kinds until 1992. That is when we discovered that you get the same energy efficiency and better performance by using a simple control valve. The CSV was designed to replace the VFD controllers. The CSV is simpler, less expensive, much more dependable, and gives better constant pressure control than any VFD unit.

See this link for more details.

www.cyclestopvalves.com/comparisons_5.html

we have had very few failures on the fe units. we also have a demo model set up in the shop. we have not noticed the rapid cycling of the pump. also, the two or three installs that we have been back to have been a customer drilling a hole through the controller, a flooded well pit, and a humidity problem. out company has a lot these out there and they work well. however, we do wish that fe could get with it and use a real transducer instead of a pressure sensing switch.

we have installed vfd units with varying tank size with no problems.

the biggest vfd problem we have had is taking water from the system between the pump and the pressure sensor/transducer. this has not always worked for us.

also, don't buy a nema 3r controller and think that you can install it outside. this has yet to work for us. it would be a great deal to use an at the well control pitless and a vfd, but none of the companies have a controller that will do it for you. the electronics fail at somewhere below zero, which is a problem where we are as we have several week periods where we don't get warmer than that.

the other benefit to all of these systems is that there is trouble shooting built right in. with the manual in hand you can get a pretty good idea what the problem is if the system fails. this is nice if you live seventy five miles away from the nearest pump repair man. you can help him make sure he brings the right stuff.

As I said the Grundfos SQE is the best of the VFD units available. This is because they do have a small pressure bandwidth to work with. Also because they have been around longer than the other brands and have had time to work out more of the bugs. However, they have made several changes to the SQE over the nine years they have been available. None of the other brands have been around long enough to know how they will last. Although the SQE has a small pressure bandwidth, when there is a small amount of water being used, such as a leak with a stream about the size of a match, the SQE will ramp up and down for a short while then fault out. A dripping faucet or running toilet seems to be the death nail for any of these VFD units.

Franklin switched to the switch instead of the transducer to increase reaction speed. The older Franklin units and any other VFD that uses a pressure transducer does not react fast enough. When the sprinkler system is turned on these units react so slow that the little bladder tank bottoms out and causes tremendous water hammer. When the sprinklers are turned off, the VFD reacts so slow that the pressure spikes and blows something up before the pump has had time to slow down.

It is good that these type units have troubleshooting built in, because it is one feature that is used often. A VFD is a computer. Let a computer control your pump system and you will go thirsty. When home computers blink out you are inconvenienced. When a VFD computer blinks, you are out of water.

The CSV gives the same performance and energy efficiency of a VFD with the simplicity and dependability of only one moving part instead of a computer. Many people have switched, and continue to switch to CSV from VFD everyday.