Well pump and heat pump

[Dirtmover]

I just stumbled across this forum and it looks as though some of you may have the expertise to answer a few questions.

I have a water sourced heat pump that is fed from the same well as my house water.

The setup is 1hp well pump -> PRESSURE REGULATOR -> pressure switch/gauge -> pressure tank then off to the furnace and house supply. The well is 200ft. Pretty typical setup apart from the regulator.

The regulated pressure is set to a few psi above the cut off setting of the pressure switch. The installer indicated that the regulator is required to prevent the well pump from cycling when the heat pump is on. When the water is flowing the pressure never reaches the cutoff pressure due to the regulation.

Is this a valid configuration? To me it would seem logical that at best I am consuming more energy than necessary just to create back pressure at the pump and at worst may be damaging the pump and or plumbing on the well side of the regulator.

If this is a bad configuration what should I do to remedy it?

I realise that the ideal would be seperate wells or pumps for the house water and furnace but neither of these is possible with my current configuration.

This setup has been running for 7 years now but I have noticed over the last year that the steady state pressure reading while ONLY the heat pump is on is gradually reducing. A year ago it was settling at about 47psi it is now settling at about 43psi but it also seems to fluctuate a bit with time.

Do well pumps loose the ability to pump as they wear?
Do I have a leak before the regulator? There is no air ingress so I don't think so.
Would I expect the pressure to change as the water depth in the well changes? And if so just how much would I expect the water level to vary by?

Advice or suggestions?

 

[Bob NH]

You apparently have something that works becuse it has worked for seven years.

Pumps can lose capacity or pressure capability as they wear. If the water level in the well falls, then you will see less pressure at the surface.

Where are you putting the water after it goes through the evaporator of the heat pump?

It is virtually certain that supplying a heat pump and a household with a single pump, and dumping the heat pump water to waste, is using more pumping energy than would be used by a system that uses a two-pump system. If you are satisfied with the power consumption, then you should leave it alone. If you are not satisfied with the power consumption then someone could look at it and suggest alternatives. The question then becomes, do you save enough with the improvements to pay the capital cost of the changes that would be required.

 

[Sponsor]

 

[Bob NH]

I have a water sourced heat pump that is fed from the same well as my house water.

The setup is 1hp well pump -> PRESSURE REGULATOR -> pressure switch/gauge -> pressure tank then off to the furnace and house supply. The well is 200ft. Pretty typical setup apart from the regulator.

The regulated pressure is set to a few psi above the cut off setting of the pressure switch. The installer indicated that the regulator is required to prevent the well pump from cycling when the heat pump is on. When the water is flowing the pressure never reaches the cutoff pressure due to the regulation.

My earlier response was that "You apparently have something that works becuse it has worked for seven years." That was based solely on your reported experience. I hadn't done any analysis of the setup.

If I understand your description correctly, there must also be some kind of valve that allows water to flow through the evaporator of the heat pump system. When that valve is closed, the regulator allows enough pressure to turn off the pressure switch. When that valve is open, the system draws enough water that the pressure drop through the regulator is enough to prevent the pressure from rising to the shutoff pressure of the switch.

There is probably a throttling valve in the heat pump evaporator circuit to adjust the flow so that it doesn't pull the tank pressure down too far. If you open that valve more (or if it becomes worn) it will pass more water and the pressure in the tank will be reduced. It is also possible that the gauge is beginning to drift from calibration.

On the other hand, if the valve has not been adjusted and you are getting lower pressure because the pump is less effective, then you will be getting less flow through the evaporator and will be making that system less efficient.

You should have some specification on how much water should be going through the evaporator. You should be able to adjust the the evaporator throttling valve, or the regulated pressure, or both, to get the desired flow and tank pressure.

 

[Gary Slusser]

With the info provided, other than what I suggested above as possible problems with this system, I have no other ideas of what might be wrong, if anything.

So Dirtmover, what gpm is the 1 hp pump?
What depth is the pump set at in the 200' well?
What is the static water level in the well?
What is the recovery rate gpm of the well?
Does the pump cycle on/off at all when just the heat is running?
What flow control or max gpm is the heat pump?
How many bathrooms?
How many people in the house?
How many bedrooms?
Where does the water go after the heat pump?

Although I've done water treatment on a few, I don't know much about using well water for a heat pump but I believe the flow is usually controlled by a static flow control; usually a button type. There may be a minimum pressure requirement with that. The pressure isn't controlled except by the pressure switch to operate the pump.

If this one is flow controlled (and I think all have to be) then, as stated, the PRV is supposed to limit pump starts but... if the heating system flow control can't accept the total output gpm of the pump at the pressure setting of this PRV or less like now, the pump will still cycle.

Raucina and BobNH, unless there are two wells, one for the heating and another for the house, I do not beleive there is any way to use two pumps in one well unless the well was a large enough diameter to accept 4" pumps and the drop pipe and cables for both; allowing the drop pipe and cable past one of them. And then should the heat be a closed loop dumping its water back in the well or not? If not, the recovery rate of the well would have to be quite high, especially with say a 2.5 bath or larger house.

Larger diameter wells usually cost considerably more than smaller diameter wells, and then two pumps, pressure tanks and switches cables and drop pipe with accessories would be a much more expensive system, so how would you justify that huge additional expense when one regular 4-6" well with one pump is the norm and works just fine?

 

[Speedbump]

I'm wondering what the valve he has; is. It sounds like the Well Driller installed a CSV. Would that be a stretch? I think not. Lots of Well Drillers are using them. Like Gary said, it's real difficult to use two pumps with one well. So that leaves what many of have been saying for months now. The CSV is the answer to this type of system. Among others.

Dirt Mover, can you describe this pressure restricting valve to us? Maybe find a brand name or model number? I would appreciate it if you could.

"Edit" I forgot, you asked if this is a valid configuration. Absolutely. With only one well and pump you have no choice. If you let that pump cycle instead of running continuously, your motor would probably have been toast a long time ago.

bob...

 

[Dirtmover]

Wow, much more info than I expected!

To clarify a bit more detail on the setup:

- well pump
- Watts 25AUB regulator set to about 55psi
- pump pressure switch set to 30/50
- guage
- pressure tank
- split to house supply and furnace

Then on the heat pump side we have
- a second regulator to restrict the flow into the furnace
- the main supply valve on the discharge side

The water is discharged into the ground. Not sure exactly where? There may be another well, gravel bed, really not sure but it's certainly not visible.

When the furnace is on the well pump runs continuously due to water demand. When running water in the house only, for example when showering, the pump cycles.

Not sure about the flow through the furnace. It has been set based on discharge temperature and is high enough that the discharge water is at a temperature of about 3 deg C. Any slower and it will freeze.

I think my questions have been answered as to the validity of the setup.
I will re-check regulator settings, guage, and furnace discharge temperature and if all are ok assume it's probably pump wear or water level.

 

[Gary Slusser]

I can't see how the switch/pump can stay on when it is set at less than the PRV valve and then the water flow is reduced/held until the temp is 3*c.

You didn't answer my other questions but what size water line to the furnace?

 

[Raucina]

If you have a 6" well, and use poly pipe, 2 pumps and 1" pipe fit quite easily when staggered and tied together. I have this setup on a shared well, and I suppose a third pump would fit also, although you would have to fabricate a well seal for all the hardware coming up to surface. Sounds like your regulators are serving you nicely, and for several years.... so maybe the pump is just seeing some wear - get good liquild filled pressure gauges and watch its performance over time.

 

[Dirtmover]

If you have a 6" well, and use poly pipe, 2 pumps and 1" pipe fit quite easily when staggered and tied together. I have this setup on a shared well, and I suppose a third pump would fit also, although you would have to fabricate a well seal for all the hardware coming up to surface. Sounds like your regulators are serving you nicely, and for several years.... so maybe the pump is just seeing some wear - get good liquild filled pressure gauges and watch its performance over time.

A second pump would have been my ideal choice but we are living with the previous owners installation decisions. The peace of mind of always having a backup source of water available in the event of the house water pump failing would have been worth the additional up front cost. To retrofit at this stage does not make economic sense.

Alas, at 18 years the furnace is probably reaching the end of it's life and I'm not sure if we'll replace it with another heat pump or go with natural gas.

Now, as far as a good liquid filled guage is concerned. I'm guessing you're not talking about the type available for a few bucks at the Home Depot?

 

[Dirtmover]

I'm wondering what the valve he has; is. It sounds like the Well Driller installed a CSV.

Until yesterday I'd never heard of a CSV. I have done some reading and I now understand how they are working and no, this is definately NOT what I have.

Bob has given an accurate description of how my setup is working, better than I did:

The system has been engineered and adjusted to operate as described by the owner, without cycling the pump. The regulator is set so that when the furnace is demanding flow, that flow causes enough "droop" in the regulator to keep the pressure below the pressure switch setting. When the flow to the furnace is shut off, the regulator delivers enough pressure to shut off the pressure switch.

The functionality provided by my setup is idential to that provided by the CSV though the method of achieving it is completely different. Given that you can reliably achieve the same results as the CSV with an inexpensive, off the shelf, mainstream regulator why would anyone pay a premium for what is a niche market product? I don't see any real advantage to the CSV.

The prices suggested here http://www.cyclestopvalves.com/prod_prices.html for a "non-weeping", adjustable CSV are about 10 times what I would pay for the regulator I have!

 

[Gary Slusser]

I'm suspicious of this whole thread and have been since I read the first post. As it has gone on, I'm pretty sure it's a spoof to support those against the CSV.

Here's some info on the PRV mentioned.
https://terrylove.com/watts.htm

The lowest price I could find for a 1.25" was $157.00 w/o shipping on the internet.

I wouldn't use one of them on a submersible pump.

It's been suggested to put two pumps in a 6" well. Unless it is a fully cased well and not a cased into the bed rock only rock bore type, I would not put a 4" pump, possibly 30+" long, with a 1 3/8" OD PE drop pipe run past the pump in a 6" hole which leaves less than 3/8" of clearance around the pump, and then expect to not have any problems getting them out when needed years later. Hell iron alone can take up more than 3/4" (3/8"*2). 1" PE pipe is IPS meaning the ID is maintained and the OD is larger, unlike copper tubing where the OD is maintained althugh we call it by its ID; I.E. 3/4" is actually 7/8". And then the 160 psi rated is larger OD than 125 psi but smaller OD than 200 psi rated. Many times it is a bit difficult to get a 4" pump out of a 6" rock well and the deeper the pump, the more apt there will be problems.

Dirtmover wouldn't go with a CSV because of the price, but would spend a lot more money for a second submersible pump, drop pipe and cable etc. to have a spare system in case there was a problem with a single pump system... just doesn't make sense to me. Until I realize how much he sounds like dozer owner dirt movin' Raucina who has two pumps in one 6" well.

 

[Speedbump]

To clarify a bit more detail on the setup:

- well pump
- Watts 25AUB regulator set to about 55psi
- pump pressure switch set to 30/50
- guage
- pressure tank
- split to house supply and furnace

Then on the heat pump side we have
- a second regulator to restrict the flow into the furnace
- the main supply valve on the discharge side

Unless I just don't understand plumbing, I don't see any reason to have a Watts valve set at 55lbs. when the pressure switch is set at 30/50. Can anyone explain to me why this is? The Watts valve would never see the 55 lbs. that is set for since the pressure switch is going to shut the pump off 5 lbs. earlier. So the cycling goes on. The only reason the pump doesn't cycle with the heat pumps running is because the amount of water being used doesn't allow it to. The Watts valve is totally useless for this reason.

I agree with Gary, this whole thing sounds like a big spoof and the writer is making things up as he goes along. What a waste of people's time.

bob...

 

[Dirtmover]

Gary, I have no affiliation with Raucina and really have no desire to get involed in any petty bitch fighting between you guys.

Seven years ago the regulator cost me CAN$35 at the Home Depot. I replaced it because the previous regulator had failed. The well pump was replaced at the same time. The guy that installed the pump told me how to set it up. The same regulator now costs CAN$45 at the Home Depot.

The facts stand:-

- My setup has been running in this config for 7 years
- It ran for 11 years previous to this with the original owner with the same config.
- I have a system that externally looks like it's using a CSV
-...but it uses a $45 off the shelf regulator rather than a $450 CSV

So Gary, can you please explain why you would not use this regulator with a submersible pump?

If I had made the original install decisions I would have isolated the furnace and house water supplies either by installing a second pump for the furnace or using a closed loop system.

It gets cold here over winter and when it is -20C outside the pump can run for up to 15hrs per day. It only makes sense to minimise the pumping requirements,

My opinion is that a CSV "type" of setup for this application, regardless of how it is implemented, is no more than a hack. It does, however, appear to be a legitimated and accepted solution which was the original thrust of my questioning.

BTW, I don't own a dozer but here have been times I wish I did.

 

[Speedbump]

The functionality provided by my setup is idential to that provided by the CSV though the method of achieving it is completely different. Given that you can reliably achieve the same results as the CSV with an inexpensive, off the shelf, mainstream regulator why would anyone pay a premium for what is a niche market product? I don't see any real advantage to the CSV.

Your setup is in no way setup like a CSV setup would be. Your pressure settings won't let the valve do anything. Your valve doesn't have the ability to let the tank fill slowly like the CSV and your pricing is way out of whack. Go try to sell this story to Readers Digest, I'm not buying it.

bob...

 

[Dirtmover]

The Watts valve would never see the 55 lbs. that is set for since the pressure switch is going to shut the pump off 5 lbs. earlier.

If you mean the house side of the regulator never reaches 55psi, then correct, it doesn't. It's not supposed to.

As I pointed out, Bob NH explained how it works quite eloquently a few posts back. I really didn't think it was that complicated!

 

[Bob NH]

Alas, at 18 years the furnace is probably reaching the end of it's life and I'm not sure if we'll replace it with another heat pump or go with natural gas.

I would not be in a hurry to replace the heat pump with gas.

I just did a calculation comparing natural gas and electricity where I live. Your prices are different but the factors are the same.

A good open loop ground source heat pump system has a coefficient of performance of at least 3.5. To deliver 1,000,000 BTUs to the house requires:

(1,000,000 BTUs)/(3.5 COP x 3413 BTU per kWH) = 83.7 kWH

Gas furnaces operate around 90% efficiency unless you are using the condensing boiler type; so to deliver 1,000,000 BTUs to the house you must burn:

(1,000,000 BTUs)/(0.90 efficiency) = 1,111,000 BTUs of gas.

I checked a web site that gives a price for gas delivered to the home in New Hampshire by pipeline at about $14 per million BTUs.

I pay about $0.12 per kWH for electricity.

So to get 1,000,000 BTUs of heat I would pay:

$0.12 x 83.7 kWH = $10.04 for electricity to run a GSHP, or

$14.00 x 1.111 MMBTU = $15.55 for natural gas to burn in my furnace.

I have no idea how the costs of gas and electricity compare where you are, so you would have to plug in your own numbers.

If I had a water supply such as you have, I would look at how to get maximum performance from the pumping system, compressor, and heat exchangers. I could easily beat the cost of gas or fuel oil here in New England.

 

[Valveman]

We use a Watts regulator to make our CSV1W valve. Watts is what the W stands for. By setting a standard regulator for 55 PSI and having a 30/50 pressure switch, you are using the "reduced pressure falloff" to set the minimum flow through the regulator. With that valve you have 5 PSI of "reduced pressure falloff" at about 8 GPM. That means that with the valve set at 55 PSI you have a minimum flow of 8 GPM at 50 PSI when the pump shuts off. That is why your heat pump, which uses more than 8 GPM does not cause the pump to cycle, and when you use water in the house you are using less than 8 GPM and the pump cycles on and off. The trick of the CSV is getting the flow down to 1 GPM reliably without causing the pump to cycle. Eliminating the cycling while the heat pump is running is a good thing and is why the first pump lasted 11 years. With a real CSV keeping the pump from cycling for all other uses as well, the pump would probably have lasted 15 or 20 years instead of just 11. Those standard regulators are the fully closing type which can easily dead head and burn up the pump/motor. If you try to set these valves to use very low flow without cycling, you need to set the reg at 51 PSI with a 30/50 pressure switch. Now the setting of the regulator is very close to the off setting of the pressure switch. Just the slightest turn of the screw too low on the reg or too high on the pressure switch and the reg closes completely before the switch shuts off the pump, and dead head occurs burning up the pump. Even a slight temperature change can make these kinds of differences in the spring adjustments causing the pump to dead head.

This was the first way that people tried to make a constant pressure valve and it worked fairly well. The principle is identical to the CSV except for the possibility of the valve closing fully and dead heading the pump. It was a smart pump man that figured that out and it has been used for decades. Next they discovered that if they drill a small hole through the valve body, they could actually set the reg at or below the setting of the pressure switch and the hole made the minimum flow accurate and sort of dependable. This is the way other companies such as Flomatic, Aqua Genie, Smart Tee, and others have been doing it for years. Now the problem is the velocity of water through the small hole causes minerals to build up and will stop up the same as the holes in your shower head do. When the hole is plugged with minerals, the pump is destroyed from a lack of flow. The only difference in these valves and the Cycle Stop Valve is that we use a half moon shaped notch on the valve seat instead of a drilled hole. When the valve closes it makes a 1 GPM hole. When the valve opens it splits the hole in two halves and dislodges any debris or build up that is present. This eliminates the possibility of the hole plugging up and allows us to set the valve below the off setting of the pressure switch. This guarantees a minimum flow of only 1 GPM. which keeps the pump from cycling as long as you are using at least 1 GPM.

So yes guys this valve works just as Dirtmover says. The problem is that you can't adjust the "reduced pressure falloff" to much less than 8 GPM or the valve settings and the pressure switch settings are so close together that deadheading is a real possibility.

Explain the notch of the CSV to the pump man who has been using the "reduced pressure falloff" or drilling holes in regulators to set the minimum flow, and he will say "that is so simple I should have thought of it myself". Well the more simple a useful device is, the more important a patent. The US patent system was designed to show EVERYONE exactly how to make and use beneficial products. For showing everyone how to make them, the patent holder gets a few years of protection and can charge a little higher price. BTW your valve should have an internal screen. The Screen is probably clogging up with debris or minerals as I described which is causing the lower pressure you are seeing. If you remove the screen and make a simple notch in the right place, you have made a CSV. The idea is so simple that after the patent is no longer protected, everyone can begin making their own. Until then my patent lawyers would love for someone to start making their own version of the CSV. Your Watts regulator has proven that the theory is sound, the CSV just makes it dependable and safe to go to a much lower flow rate.

 

[Valveman]

When the patents run out you won't have to make your own CSV. There are several companies laying in wait to start making cheap copies of the CSV. That alone should tell you how good the CSV works.

I tried pins in the hole, screens for the hole, different angle and shaped holes, and lots of other ways. The only thing that really worked was making the hole bigger which defeats the purpose of the small minimum flow needed.

Then with valves larger than 1 1/4", the notch has a couple of completely different jobs to accomplish. The notch keeps the valve from ever completely closing, which eliminates "hunting". "Hunting" is a quick pressure surge in fully closing valves that will not stop. Also because the notch keeps the valve from closing completely it eliminates water hammer. The notch also allows us to speed up the action of the valve tremendously. Fully closing valves, even with a hole drilled out or a tube around them, cause water hammer on opening and closing. This makes it necessary to use speed controls to slow down the opening and closing speed. Now the valve cannot react as fast as changes are happening in the field causing pressure surges, water hammer, and short cycles the pump. The non closing design of the CSV allows us to make valves as large as 16" to control a 10,000 GPM pump and still operate as fast as any changes in the field. Fully closing valves cannot do that!!! The only place where a standard regulator valve can come close to the operation of the CSV is with 1 1/4" or smaller valves, because they are so small that water hammer and reaction speeds are not as critical. With these smaller valves, stopping up the bypass hole is the critical issue which has been solved with the simple notch in the CSV.

 

[Gary Slusser]

Raucina et al, the bottom line is as I've been saying... no PRV will work automatically consistently without maintenance on any type of water in any well everywhere, near as well as the CSV. Nor in most cases if any will, will the PRV prevent pump cycling and extend the life of pumps.

 

[Gary Slusser]

My opinion is that a CSV "type" of setup for this application, regardless of how it is implemented, is no more than a hack. It does, however, appear to be a legitimated and accepted solution which was the original thrust of my questioning.

The original thrust/hack was decades ago and was to prevent the pump from cycling on/off until it kills the motor/pump while adding substantially to the electric bill. The CSV does that better than any other solution; or hack as you call it. I think you should note that the CSV is a patented hack.

Personally, I like the simplicity and low cost of the CSV best when compared to the expensive variable speed or frequency pumps and their controllers that ex-urban transplanted type suburbanites desire today.

I think your PRV may be blocked up or isn't preventing cyclying as well you think it has been. When you fix the problem, let us know what was found.

BTW, Raucina has the dozer.