New 1HP well pump: Do I need a Control Box with both RUN and START capacitors ?

Users who are viewing this thread

iamjcl

New Member
Messages
16
Reaction score
0
Points
0
I'm replacing my 2HP submersible pump/motor/control box with a 1HP for a geothermal HVAC system, in order to reduce power consumption (1/2 the HP, but also 1/2 the pressure - I'll have to use a booster pump for irrigation now...)

Anyway, the Grundfos motor / pump-end only has a corresponding 1HP control box with a start capacitor - They (Grundfos) don't make a box that has start and run caps until 1.5 HP. I've been told that start / run boxes are more efficient.

Since the entire point of changing out my pump is to reduce energy use, should I use a Franklin control box with the Grundfos motor (Franklin does make a 1HP 2-capacitor control box, but I don't know if it would be wise to "mix and match" motors and control boxes) or should I just go with the simple start-capacitor-only Grundfos 1HP control box?

My pump motor use averages over 350 hours / month over the last 2 years, so run time is pretty significant.

Thanks for any help with this.
 

Texas Wellman

In the Trades
Messages
1,035
Reaction score
59
Points
48
Location
SE Texas-Coastal
The "big" control box uses slightly less electricity because it engages the start winding with the run winding on a Franklin. I can't speak about the Grundfos, I really don't see too many.

I do know from experience that you can use a Franklin box on a Grundfos pump. I would put in a 1-HP Franklin "big box" (they make one that will fit either 1 or 1.5 HP). It should work. The amps difference is only slight so I'm not sure if you're really gaining anything. Might be best to measure before/after wattage to see the difference.

Best of luck.
 

iamjcl

New Member
Messages
16
Reaction score
0
Points
0
Thanks for the info - with the cost of the motor/pump, I just want to use the best box period - the difference in cost between boxes is minimal. I also don't want to possibly shorten the motor's life or anything - Maybe it would be best to just use the basic Grundfos "1HP" box, I just don't know what the power useage difference would be.
 

DonL

Jack of all trades Master of one
Messages
5,205
Reaction score
72
Points
48
Location
Houston, TX
Thanks for the info - with the cost of the motor/pump, I just want to use the best box period - the difference in cost between boxes is minimal. I also don't want to possibly shorten the motor's life or anything - Maybe it would be best to just use the basic Grundfos "1HP" box, I just don't know what the power useage difference would be.

You may want to check the pump manufactures website to get an idea about pump performance.
A lot of variables come into play with pumping systems.

In my experience better efficiency is not as important as reliability.


Good luck on your project.


Have a Happy and Safe Holiday.
 

Ballvalve

General Engineering Contractor
Messages
3,581
Reaction score
45
Points
48
Location
northfork, california
You really want a run capacitor box. Or better yet, a three phase motor which runs like a 1940 singer sewing machine next to a single phase rig. The run cap brings you a bit closer to the smooth sine waves of 3 phase. Thus reliability increases, with a bit of efficiency. Once you have a shop with 3 phase, you get sick looking at a 120 volt split phase piece of junk.

Still, I would try and get that HP down on the pump WAY lower, at the bare minimum for the sys. - even if you have to trickle feed off water to a large tank and use another submersible in there.

I just bought a 2500 gallon tank for 500$ -prices are down now.

If you run your cost numbers with even a 1 HP pump running that many hours, you will find that your investment in "geothermal", and its component lifespan and complexity, will never pay back over burning natural gas or pallets in a wood stove.

I think valveman has a geothermal, and uses a 1/3 hp pump. But unless you live next to a volcano, or hot spring, I would have never installed it.
 
Last edited:

iamjcl

New Member
Messages
16
Reaction score
0
Points
0
I would like to get the Run cap box - but is it fine to use a Franklin Run-cap 1hp box with a Grundfos 1hp motor ? That's what I'm not clear on. Grundfos doesn't make a 2 capacitor box for 1hp - only 1.5 and up.
 

Texas Wellman

In the Trades
Messages
1,035
Reaction score
59
Points
48
Location
SE Texas-Coastal
I have used the Franklin box with the Grundfos so I can say for a fact that it will work. Does the manufacturer agree with me? Maybe not. But it works.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks