Upgrade well pump and system?

Just remodeled and put in a second open loop heat pump. New heat pump is two stage with total water usage of 7 gal/min. We also have an open loop heat pump in the original house that we will probably replace with a similar open loop that will probably require at least 7 gpm. Current rock well is 30 years old, 4 inch steel casing, 248 ft deep, with 20 year old 1/2 hp submersible pump. Current feed line is 160 psi 1 inch. Water level is 29 feet below ground level and current pump sets 69 feet down with 1 inch drop pipe. Current bladder tank is Well-X-trol 302 (35 gal.?) We think we're only getting about 8 or 9 gpm with current system.

We put in a new 1 1/4 160 psi plastic feed line and 10 ga 3 wire w/g under new addition foundation that leads out to where we could put in a new well or run the wire over to the existing well if that is an option. Current well/pump is 12-2 w/g wire.

We'd like to upgrade to a new well/pump system that would give us between 20 and 25 gal/min to accommodate both heat pumps and regular water demand. I guess we have four options.

1. Use current well and replace the current pump with a bigger hp pump if it will supply us with the water flow we need. Use everything currently in place, tank etc.

2. Use current well and replace pump with Franklin 1 HP 20 gpm submersible pump and 60 psi constant pressure mechanical valve with 1 1/4 drop pipe. Some well people say the mechanical pressure valve is bad on the pump and that pump manufacture does not guarantee pump, ie. warranty is void. We wonder if it's good for the pump to try to pump all that water against the valve during low volume demand which seems to me would create a lot of back pressure.

3. Use current well with 10/3 w/g wire and Franklin Electric SubDrive constant pressure system to produce up to 25 gpm. How susceptible are these systems to lightning damage? We have friends with this system that have had to replace the control system twice due to lightning or electrical surge.

4. Drill a new well with a whole new system. What would you recommend?

We would very much appreciate detailed input and recommendations for our well and water system. Thank You!

Mickeysz said:

Current rock well is 30 years old, 4 inch steel casing, 248 ft deep, with 20 year old 1/2 hp submersible pump. Current feed line is 160 psi 1 inch. Water level is 29 feet below ground level and current pump sets 69 feet down with 1 inch drop pipe.

Click to expand...

1. Why are you using a deep drilled well for a heat pump?

Study's have shown that you are less likely to draw containments into the aquifer if you use a separate shallow well for the heat pump.

2. You need a low/pressure or "low lift" pump since you don't need full house pressure for the heat pump.

3. You are starting to get to the scale where closed loop would be better.
Note: some states place limits on the amount of water you can use open loop.

I know from personal experience that back pressure from a mechanical valve is actually good for the pump. It is varying the speed that is hard on a submersible or any pump. Instead of getting into a long conversation about that, I will just give you a link with lots of information.

http://www.cyclestopvalves.com/comparisons.html

There are lots of good reasons to use a separate well for the heat pump. Aside from the contaminants issue, you want to keep the Horse Power as low as possible. You could use about a 15 GPM, ½ HP submersible to supply both units. Maybe even a 1/3 HP pump. Open pipe from pump to zone valves on the heat pump. Thermostat triggers a relay that starts pump and opens correct one or more of four zone valves. Pressure will be a little higher when only one zone is working but, depending on the pump will be about 40 PSI max. Make sure not to cross connect from the relays on the two different heat pumps.


However, if your current well will produce about 20 GPM, you could feasiblely run everything from the existing well. If you need max 14 GPM for the two heat pumps, I would add another 5 GPM for each house, then you are on the money with about a 25 GPM pump. Use a pump with a good drop in horse power like a 25S15-9 Grundfos, or similar Hydroflo, which is a 25 GPM, 1 ½ HP pump. These pumps will naturally only pull about a 3/4 HP load when restricted with a control valve to produce a low flow rate. The more water you use the more power required. Then a regular bladder tank and pressure switch working with the valve, will make it work for the heat pumps, houses, or all at the same time. You will be using at least twice as much power this way as compared to the ½ or 1/3 HP. They too would reduce power consumption as the flow decreased, and one heat pump zone would only be using 1/5 or 1/6 of a horse power.

It depends on how much keeping the horse power down cost, compared to how much a new well and equipment cost. I would say if you can't save enough energy to pay for the extra well in about 5 years, you might want to just use the existing well.

Valveman, you were/are a great help. I went to the link you sighted and spent about 3 hours reading all the information. I also appreciate you spending time with me on the phone. I have a few more questions however.

How much different will the pressure and gpm be between the use of the CSV160 valve with 1 inch or 1.25 fittings. Plus how much difference will there be in using a 1 or 1.25 inch drop pipe? I still will be using the existing 1 inch feed into the house as we can't easily change that. I also understand that the minimum flow rate of a CSV160 valve with 1.25 fittings is 2 or slightly more gpm as opposed to the one with 1 inch fittings which gives a minimum flow rate of 1 gpm.

Plus you recommended the 60 psi valve rather than a 50 psi valve. Currently our pressure switch is set between about 40 and 55+. I'm concerned a little about what 70 psi will do to faucets and other plumbing items if the new settings are 50 and 70. Or is that not a big difference? I guess the questions is wouldn't a 50 psi valve with pressure switch settings of 40 and 60 be good enough?

Bottom line - I'd like to have a 1 gpm minimum flow rate for irrigation and top end gpm of close to 25 for two heat pumps and other house hold demands at other times. You recommended a 1 HP pump so how can I accomplish this with the well we already have or am I asking for too much?

Again, I really appreciate your help and am convince that a constant pressure mechanical system using a cycle stop valve rather than a VFD system is the way to go especially after understanding how each system works. I think I told you we have friends who are on their third VFD system in 4 years at the tune of $1100 a crack each time the VFD control panel got zapped.

If you'd rather, I can call you again. I would gladly do that if that's easier for you. Our well guy is planning to come out in about a week.

Again, thanks. I've learned a lot.

The only time you will even see any difference between the 1" and 1 1/4" valve is when you are using all 25 GPM. Then you would only see a 3 PSI difference. The 1" is better for you because it will work down to as little as 1 GPM.

I think a 1 HP 25 GPM pump would give you all you need, and should be fairly efficient when running small flow rates.

A 50 PSI valve would be plenty, and that is all you will really get with a 1 HP pump when you are using all 25 GPM anyway.

Just to make sure I understand.

With a 50 psi 1" (CSV150) valve with a 1" drop pipe and feed into the house and 1 HP pump we can get the low end of 1 gpm. With the same, what is your best guess what our top end gpm might be? Could we use a 1 1/4" drop pipe with the 50 psi 1" valve and get any more top end gpm?

I really appreciate your help. Thanks again.

The 1" CSV will have a 3 PSI loss. 1" sch 80 PVC has a loss of 20 PSI for every 100'. 1" sch 40 only has 13 PSI loss. 1 1/4" sch 80 has 5 PSI loss per 100' and sch 40 has 3.5 PSI loss.

I think you only have about 100' total but, you can't really afford the loss from 100' of 1" sch 80 and I don't like hanging pumps on sch 40. So I would use the 1 1/4" sch 80 down in the well, and you could switch to sch 40 underground. You just have to use reducers from 1 1/4" to 1" and back to install the 1" CSV. Use as little 1" pipe as you can anywhere.