What size generator?

[Rock_Hudstone]

Looking to run a well pump, oil fired furnace with two circulator pumps and a fridge, these are the essential items.

The well pump is 1/3 hp, 3.5 amp 4.4 max amp, 280 ft deep, Beckett Burner is 1.7 amps, the two circulator pumps are 2.5 amps, fridge is 19.7 cubic feet. Could a 9 HP 3250 watt/3500 surge generator safely power these?

I could easily shut off the furnace and fridge when not needed.

 

[simple_gifts]

Is the well pump 120V

 

[earlyre]

that sounds too small. I think that's about the size my brother-in-law had,and after this summer's Derecho, he could either run the fridge, tv, a few fans, Couple of lamps, OR the well pump. so he got a bigger PTO driven gen.(since they're on the farm anyway) that he can run pretty much the whole house on.

I don't honestly remember what all they were running, but i know it was their stuff -OR- the well not both @ the same time.

my dad has a 5000 W Gen, can run the Sump Pump,Fridge, tv, Few lamps, electric bits on the gas water heater & Furnace,coffee pot,etc and his Well pump, but his is a shallow well jet pump (aquifer only 25ft down)

 

[Rock_Hudstone]

Originally Posted By: simple_gifts
Is the well pump 120V

No, 230V, forgot to mention that.

 

[Teddi]

That's similar to the stuff I run when the power's out. I went with a 7500 watt peak/6700 watt continuous generator. I think you could probably get away with a 5000 watt generator, but I would not go below that.

 

[JHZR2]

Do you really need the luxury of running everything at once?

 

[Donald]

I would go with a 5000W normal 6000W peak. Nothing less with a submersible well pump.

Your current draw for the well pump sounds low. How did you measure that?

Does the well pump have 2 wires + ground or 3 wires + ground. That will tell you where the starting capacitor is. Better to have the capacitor in the basement in a control box (3 wires + G), than part of the pump. A 3 wire + ground draws less power.

Hopefully you have the newer cartridge style boiler circulation pumps than the older/larger red B&G pumps.

Get or borrow a digital peak hold clamp on ammeter and go about measuring everything.

Get a 6 to 10 circuit transfer switch. (Pump will take 2). When the power goes off and you get the generator running, transfer the oil boiler, let it get fully going, heat flowing, then the refrig. Wait on the well pump. You do not need it right away. By the time you need it, the power may be back on, and/or the refrig will be to temp, and the heat will be cycling. Assuming you have a normal blue "captive air" well pump tank, you can run the faucet until there is no water and it does not disturb anything.

Worse than loosing power is loosing power AND blowing your well pump due to low voltage.

 

[Zaedock]

I burn wood, and actually haven't turned the heat on yet (oil, hot water), but I get by with a 4000W which powers my boiler, lights and fridge. Given your load, I wouldn't go below a 5KW.

 

[rjundi]

My neighbor uses a 4000W/5000W peak with a similar load without major issue.

The only time it really matters is if well, boiler, and fridge start at the same time. The well cycles but hitting the other one or two at same time is rarer.

 

[rjundi]

Originally Posted By: JHZR2
Do you really need the luxury of running everything at once?


If you like showering

you need well pump and boiler.

 

[Rock_Hudstone]

Originally Posted By: Donald
I would go with a 5000W normal 6000W peak. Nothing less with a submersible well pump.
Your current draw for the well pump sounds low. How did you measure that?

-Took the info off the control box.

Hopefully you have the newer cartridge style boiler circulation pumps than the older/larger red B&G pumps.
- Nope, one is a red Bell & Gossett pump, the other a different brand but similar size. They are tanks but run forever.

Worse than loosing power is loosing power AND blowing your well pump due to low voltage.

-Yikes, definetly don't want that to happen. Lord only knows what a new well pump and lines would cost these days.

 

[JimPghPA]

Regarding your "the two circulator pumps are 2.5 amps, fridge is 19.7 cubic feet"

1) Is that 2.5 amps each, or 2.5 amps total for both of them?

2) How old is the 19.7 cubic feet fridge? Old refrigerators draw much more start and run current.

 

[JimPghPA]

BTW your assuming your well pump is 120, not 240 regarding your "well pump is 1/3 hp, 3.5 amp 4.4 max amp" probably has a start up surge somewhere between 6.5 to 13 Amps, and if I had to chose a start current just by guessing I would be guessing 11 Amps.

But the real way to figure this out is to get someone with a digital multi-meter that has peak hold and an AC current scale.

 

[Rock_Hudstone]

Originally Posted By: JimPghPA
1) Is that 2.5 amps each, or 2.5 amps total for both of them?

2) How old is the 19.7 cubic feet fridge? Old refrigerators draw much more start and run current.

2.5 amps each on the circulator pumps, fridge is about 20 years old, GE side by side.

Well pump is 230 volts.

 

[Donald]

The refrig probably has a defrost cycle that runs at points in time and uses more electricity. So if you do actually measure things, take that into account (although I am not sure how to get it to come on to measure it).

HF sells a digital peak hold clamp-on ammeter for not a whole lot. Given that you will be spending some $$, get one ($25) and do things right rather than guessing.

 

[Cujet]

I generally recommend generators by HP. Not by rated watts.

A 9HP generator will generally start and run a 1.5 electric pump motor, without difficulty. A submerged pump can be a little different, as submerged pumps really do work hard, and they are on the end of a long wire run (more power is often necessary) .

My TN property has a small, low pressure 200 foot submerged pump and the HF 3500W generator will "just barely" start and run it. AND, it won't run anything else at the same time.

My 11HP Subaru powered genset will run it without trouble. Along with other consumers at the same time.

 

[Donald]

Originally Posted By: Cujet
I generally recommend generators by HP. Not by rated watts.

A 9HP generator will generally start and run a 1.5 electric pump motor, without difficulty. A submerged pump can be a little different, as submerged pumps really do work hard, and they are on the end of a long wire run (more power is often necessary) .

My TN property has a small, low pressure 200 foot submerged pump and the HF 3500W generator will "just barely" start and run it. AND, it won't run anything else at the same time.

My 11HP Subaru powered genset will run it without trouble. Along with other consumers at the same time.



Two comments:
1) More OPE is being sold by displacement rather than HP these days.
2) The depth of the pump makes no difference. Its how far down the water is. If the pump is down a mile and your water starts at 100' down, you are only effectively pumping it 100'.

 

[Cujet]

Originally Posted By: Donald

Two comments:
1) More OPE is being sold by displacement rather than HP these days.
2) The depth of the pump makes no difference. Its how far down the water is. If the pump is down a mile and your water starts at 100' down, you are only effectively pumping it 100'.


HP and displacement are very nearly interchangeable at 3600RPM.

330cc's makes 11HP with an overhead valve engine.
270cc's makes 9HP with an overhead valve engine.

Side valve engines produce only slightly less HP per displacement at 3600RPM.

And, I agree with your depth of pump statement. However, you may also want to consider the fact that many submerged pumps use the volume of the well as a reservoir. So, the water level may be 35 feet when full, but 240 feet when drawn down after heavy use.

Some wells flow very little (my TN well flows about a gallon per minute after fracking) I can easily deplete it if I leave a hose running.

 

[JimPghPA]

Originally Posted By: Rock_Hudstone
Originally Posted By: JimPghPA
1) Is that 2.5 amps each, or 2.5 amps total for both of them?

2) How old is the 19.7 cubic feet fridge? Old refrigerators draw much more start and run current.

2.5 amps each on the circulator pumps, fridge is about 20 years old, GE side by side.

Well pump is 230 volts.


The 20 year old fridge is a BIG concern. It could easily have a HUGE start up current draw. Something like a fraction of a second of as much as 18 Amps will not trip a 15 amp breaker, but it is one heck of a lot of current to ask from a generator.

And while the start current could be lower you really do not know any of these stat currents until you measure them. But I would be very concerned about the start current of a 20 year old fridge.

 

[Donald]

Originally Posted By: JimPghPA
Originally Posted By: Rock_Hudstone
Originally Posted By: JimPghPA
1) Is that 2.5 amps each, or 2.5 amps total for both of them?

2) How old is the 19.7 cubic feet fridge? Old refrigerators draw much more start and run current.

2.5 amps each on the circulator pumps, fridge is about 20 years old, GE side by side.

Well pump is 230 volts.


The 20 year old fridge is a BIG concern. It could easily have a HUGE start up current draw. Something like a fraction of a second of as much as 18 Amps will not trip a 15 amp breaker, but it is one heck of a lot of current to ask from a generator.

And while the start current could be lower you really do not know any of these stat currents until you measure them. But I would be very concerned about the start current of a 20 year old fridge.


Make a short extension cord where the hot and neutral wires are a few inches apart (ground if needed). Clamp the ammeter over the hot or neutral (not both). Use the extension cord with your refrig to measure draw.

This meter has peak hold. The cheaper HF one does not.

http://www.harborfreight.com/clamp-on-digital-multimeter-95683.html

Military generators have a peak of 300% while the ones at HD have 20% peak. Huge difference.

If you do not have a nearby HF, I can mail the item to you, as I will be there Sunday.