Water pump..

Is it connected with flexibles? I have found that a ceramic plant tray under the pump say 8" x 12" x 1" with carpet underneath works rather well. The tray is so heavy, that it cannot vibrate easily and damps the noise. The tray also collects any stray drips from the pump, as the manufacturers reckon that some leakage is probable sometimes.

Regards Capitol

Chop out the floorboards and stick in a paving slab instead?

Might be an idea..

That's something to consider. Seems having something heavy and insulated from the floorboards is the key. The pump is connected via flexible pipes. From the sellers website description: "FEATURES ; Quiet operation and smooth system performance" LOL

Just done the same myself with the Salamander 3.3bar. Yes, its noisy. Well, noisier than I had hoped. It has been running for a few weeks and we don't notice it much now, but guests in the bedroom next to the airing cupboard certainly do! I have mounted it on the foam feet that are supplied, then onto a paving slab, then 3 layers of carpet underlay on the floorboards. It is also boxed in. I reckon most of the sound travels through the water in the pipes, although I can reduce some resonance by moving the pump slightly. Still at least the bath fills in 3 minutes now instead of 15!

Bob.

Just done the same myself with the Salamander 3.3bar. Yes, its noisy. Well, noisier than I had hoped. It has been running for a few weeks and we don't notice it much now, but guests in the bedroom next to the airing cupboard certainly do! I have mounted it on the foam feet that are supplied, then onto a paving slab, then 3 layers of carpet underlay on the floorboards. It is also boxed in. I reckon most of the sound travels through the water in the pipes, although I can reduce some resonance by moving the pump slightly. Still at least the bath fills in 3 minutes now instead of 15!

Bob.

What you need is MASS. A great big roll of lead under it....

Yep. Lots of MASS is waht you want

Using something heavy to mount the pump on is a good idea for all the reasons already mentioned. But it won't be very quiet if there's still another way for the vibration to get transmitted.

You do mention that you're using flexible pipes. It may be too late to change anything, but flexible pipes work better at reducing noise transmission if they run in a gentle curving path and aren't pulled tight. Ideally you want to be able to move them a little once they are installed. That way, they won't do such a good job of transmitting the vibration straight into the pipework, which will do an excellent job of conveying that vibration all over your house.

I'd be inclined to use a few feet of plastic water pipe to connect between the flexible coupling and the copper that's used in the rest of the house.