How close to the pump do I reduce from 1 1/4" to 1"?

[Buczar]

I'm installing a pump in my cistern which will service my sprinkler system. The pump discharges at 1 1/4 inch. I have a bronze reducing bushing (1 1/4 to 1") and brass 1/" nipple. At what point should I make the reduction? Right at the pump or after I lift the water out of the cistern somewhere downstream (say at a point where I connect to the 1" sprinkler lines).

Thanks for any help!

Buczar

 

[Leejosepho]

How many 1" sprinkler lines? If you have several, I would run the 1-1/4 to a manifold feeding them.

 

[Sponsor]

 

[Reach4]

It might make a difference whether you are going to be pumping 50 GPM 1000 ft vs 10 GPM 50 ft.

I don't know where you would draw the line, but I think there are tables that show the pressure drop per foot at a given flow rate.

Check you PMs.

 

[Buczar]

Thanks to both. Some added info:

My longest run is no more than 100'.
My yard is flat. Probably not more than 2' of rise from the manifold point (the pump will be lifting 6ft to get out of the tank). The front may drop 3' at most.
It would appear the installed valve manifold is already at 1" so not sure I could go back up (but if I should . . .).
We should be pumping 15 to 20 GPM if I'm reading the charts right.

Is there any harm in reducing right at the pump discharge point? Should I reduce after check valve or CSV? Does it even matter significantly?

Thanks

 

[Valveman]

You should have no problem reducing right at the pump if you want.

 

[Craigpump]

Don't combine brass fittings with a stainless steel pump

 

[Buczar]

Thanks and thanks.

Ok, no brass and stainless connections I can respect (curious as to why).

And so I use PVC from the pump to the reducer?

This could work. I can run PVC up and out of tank, and will reduce right before check valve. This allows me to make use of the 1 1/4 union that I have so I can pull out the pump if needed.

I think . . .

Buczar

 

[Craigpump]

Dissimilar metals don't get along well.

 

[Buczar]

So Stainless to plastic to bronze might be ok or better to just get all stainless?

 

[Craigpump]

I like stainless, but it can be a bitch to get totally leak free. In a well it doesn't make too much difference if there is a dip, but inside a basement I'd probably use PVC between the stainless and brass

 

[TVL]

Now I'm Confused

Don't combine brass fittings with a stainless steel pump

Before I installed my F&W pump a year back, I did a lot of research and asked a lot of questions regarding dissimilar metals.

1- You are very correct in stating dissimilar metals do not get along well. However, whenever combining two dissimilar metals it is best to have them as close together in the anodic index as possible - the closer they are the better ..................... at least that is what I though I had learned?????

2- Looking at the following anodic index, one will see that brass and stainless (chromium) are next together. Since I was able to only find a brass check valve locally, I had no choice bit to combine a stainless nipple with a brass check valve.

3- Surely, this is acceptable and won't cause problems in the near future. Surely, the two dissimilar metals can co-exist for the life of the pump. Correct?

 

[Craigpump]

We see probably 15-20 low pressure conditions a year where there are dissimilar metals combined, almost every one is at the pump. Sometimes they leak within 5 yrs, sometimes they last 10, depending on water quality.