grundfos mq-45

Well I just bought the MQ-45 to use as my shallow well pump. This thing is very quiet. The main thing I was after. It has plenty of pressure. However it has this alarm thing on it that will shit it off if it thinks somthing is wrong. I get an alarm after about 5 min of it running. After looking thru the owners manual it says you will get an alarm under 4 conditions. Dry running, overheating, too low supply voltage, siezed motor. Well I am thinking it thinks it is dryrunning. That would mean that it is running out of water in the well. But I have a check valve that is about a foot from the pump. When it shuts off I can turn it right back on and it will run and pump again. I dont understand how if I was running out of water I could turn it right back on and have water again. I called Grundfos and talked with tech support about bypassing the flow switch. The guy kept telling me that the pump was fine and my foot valve was probably full of debris. I told him I could see that but why can I turn it right back on and have water? I am seriously thinking about drilling a hole in the side of the housing and adding the old square d pressure switch. I just want to take a shower now without the stupid pump turning off. Sorry for my rambling, But has anybody ever dealt with this?

fordfitz said:

The guy kept telling me that the pump was fine and my foot valve was probably full of debris. I told him I could see that but why can I turn it right back on and have water?

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And he should have explained why, it's because when the pump detects low flow, because of debris in the footvalve, it shuts off, the debris then drops back into the well, only to be sucked up again after a while when you restart.

Yes but why only when taking a shower? Maybe I wasent completly clear with the issues. It works as advertised except when taking a shower. I opened the valves to the my pressure tank. So I can make it last about 10min for a shower. It will cycle all day long fine with the toilet, sinks, dishwasher, and washing machine. But if I use alot of water like the shower it shuts off. It will only shut off on high demand water usage. Then I can turn it right back on and have full pressure for another 5 min. Thats why I dont think the foot valve has debris in it. I dont even know where the well is in my back yard. I could always dig up where it comes out of the house and follow it.

I would get a real pump that doesn't require all this nutty protection built in. I don't buy the footvalve thing, since it's down in the water. I think you'll find out the pump is defective and the sensors are set too tight and will trip it out for no good reason. In effect driving you nuts.

bob...

Or it is overheating due to sucking through that check valve, or due to the water level falling in the well, after the large water use, and that makes the pump work harder?

Why the check valve on the inlet to the pump? Neither single or two line jet pumps require them unless you have a well point type well. Or leaking foot valve...

If the foot valve is leaking, the leak could be sucking air into the line to the pump. Have you ever had a loss of prime problem?

Why did you replace the old pump and what was it doing or not doing?

I agree with the faulty pump protection. That is why I am contemplating cutting the wires to the motor and using a Square D pressure switch. The reason that I changed the old pump was it was getting extremely loud. It is in my basement and I would have to turn the TV in my living room way up. It was driving me crazy. Now this pump is extremely quiet but it cuts off. I guess I just cant win. No I have never had a loss of prime. The old pump worked fine it was just loud.

All pumps are quiet when new except the plastic ones. They sound like they need bearings out of the box.

bob...

I have some customers on the west coast who use the back pressure of a Cycle Stop Valve to quiet down their standard jet pump installations.

I am not sure you can just cut the wires to an MQ and use a standard pressure switch. You would have to completely do away with the electronic pressure switch and controller that is made into the MQ, and I am not sure that is possible. Also the MQ has a pressure tank the size of a baseball built into the back of the pump. You would need to install a larger tank if you do away with the electronics and use a standard pressure switch. I agree you would be better off, as most of the problems I hear about the MQ is related to the electronic controller.

I think you need a larger tank anyway. With the baseball size tank in the MQ, I have heard of many systems with small leaks in the house, that cause the MQ to cycle on and off rapidly to the point of causing high electric bills, and ultimately destroying the pump itself.

I have my old pressure tank that I am using now with this pump. I will cut out the electronics to the pump so to say. Then I will have just the wires going to the motor installed on a square d pressure switch. Thats a good project for the weekend.