new well dissimilar size pitless/pump discharge

I have a 1 1/4" discharge on my submersible well pump and I am stuck with a welded 1" pitless adapter at the well head. Should I install the transition fitting at the pump and use 1" pipe or at the pitless and use 1 1/4" pipe? Does it make any difference? Or is this combination inadvisable?

Submersible pump manufacturers typically put one size of fitting on the discharge for all pumps of a class. A 1 1/4" fitting is common for many 4" pumps of moderate capacity.

What you need for a pipe depends on the flow from the pump and length of pipe. If the well is not more than 300 ft to the pump, and the pump is delivering less than about 10 GPM at shutoff pressure of the tank you can get by with 1" pipe.

Most submersibles have large pressure margin at low flows so it will not make any difference in pressure delivered. It will reduce the flow a little.

The 1 1/4" pipe is a little stronger for hanging the weight if that is an issue.

Thanks, maybe a brass 1 1/4" to 1" bell reducer fitting with an added nipple into the pitless? Less things to come loose at the bottom, and the flow has to turn 90 degrees at the pitless anyway. I can't seem to find a 1'' barb to 1 1/4" npt transition fitting (or vice versa). The pump is sized for 10 gpm and will hang at 100'. The static level is at or near the top of the casing most of the time, and the well produces 8 gpm.

The "bell reducer fitting" sounds like a reducing coupling, which would require a nipple to fit into the pump.

You will have a hard time finding a 1 1/4 thread to 1" barb fitting and if you do it will be expensive.

The simplest solution is to put a brass 1 1/4" x 1" bushing in the pump head and then install a 1" brass barbed fitting (male thread) for the black polyethylene pipe. Then you will have fewer fittings to mess with where you are trying to turn the corner at the top of the well where space will be at a premium.

OK. The torque reaction down there doesn't loosen fittings like that? (is it the opposite direction so it tightens when it starts up?)

Torque acts the same on the bushing, which is what you want, as with the hose fitting. Make it tight with good teflon tape [NOT from harbor freight which is really recycled grocery bags] and you will be fine.

Fractional horsepower submersible motors start in a direction that would loosen fittings, so get them tight.

bob...

Use 1" PE from the pump up, you'll never see any difference. If you think about it, you aren't running 1" or 1.25" any farther than your pressure tank tee, past that it will be reduced to 1" or 3/4". We've used 1" on 1.5 hp pumps down 500'.

I suggest you go to any pump or plumbing supply house and ask for a SS 1" insert/barbed x 1.25" MPT regular length fitting. I'd use the SS 1 x 1.25 male instead of brass but a 1.25" x 1" reducing bushing and a brass 1" x 1" works, you just have two threaded fittings instead of one to install.

PE rolled pipe comes in black or blue.

You buy it by the psi rating and in rolls from 100' to 500' and at some places 1000' rolles. In your case a 100' roll of 160 psi is great and you get any ID in any of the ratings; 75-200 psi.

1.25" is not stronger than 1" unless it is rated @ 125, 100 or 75 psi. 200 psi is overkill for only 100' deep and your size pump.