Noise from a Flojet pump connected to a hot water dispenser and refrigerator line

[Locke]

TNot sure which location to post his thread.
I recently replaced a pump which transfers drinking water from 5 gallon bottles to my refrigerator and hot water dispenser. The line between the two is 1/2 rigid copper with 1/4" plastic from the new Flojet pump to the copper 1/2" line then it reduces back down to the 1/4" copper at either the refrigerator or hot water dispenser connections. My old pump just hummed when it came on and off, very no intrusive. Now the lines are very loud when the water is feeding through the pipes. It is by demand only when there is a need for water from the dispenser or the water line to the frig. I thought it might be loose pipes, so they have all been secured with foam at all strap locations. Could it be the copper coil behind the frig that is vibrating? It's similar to water hammer but only when the pump is running. Any suggestions would be helpful.
Tech Info about the pump: 115 VAC 6' (1.8m) cord w/ plug 3.0x5.5x7.5 (76x140x190) 1/4" x 20' (6.1m) 40 psi (2.8 bar) 1.0 GPM (3.8 LPM) at open flow NSF and Standard 18

[Bob NH]

I think you have a positive displacement diaphragm pump that operates in a high-speed pulsating mode. The pulsations are part of the systems, as is the noise that goes with it.

If you want a quiet pump and need only low flow at low pressure then you can probably use a peristaltic pump.

[vaplumber]

I agree with Bob. If I remember correctly the flojet 1.0 gallon pump is a diaphram pump much like the Shurflo units that we used to install in motorhomes. They use either a 2 chamber or 3 chamber diaphram with a wobble plate attached to the motor. This wobble plate pumps the diaphram in a back and forth motion. The demand switch, or pressure switch, whatever you want to call it, is attached to the very end of the pump head. They are loud when new, but just give this thing a few years of wear and have a listen! They are a decent pump for the size, and if you have a place to locate the pump where you dont have to hear it, it should live a decent life!

[Locke]

Thanks for the info. Just wanted to be sure not to have to worry about the pipes. Your descriptions are correct about the type. It is a great demand only pump for the water bottles (no need to re-prime either). The only time there is noise is when it is running for the ice maker or for the water dispensers. I'm getting used to it. The pump is in the basement, so the noise isn't too disturbing.