FP1 Faults & Lockouts

Yes there are flowmeters. I wouldn't change pipe size yet until you know you have maximized GPM in given pipe. While Mark is correct you are not going to get much more than 6 GPM, if the system is designed correctly and lake temperatures don't drop below a minimum, you might be okay. If not then you can ask the contractor to share in the digging.

Have you ever seen a flow center? All the grundfos pumps are vertical in those......

 

Glad to help. I saw your post when it went up but did not notice the pipe size until today.

I have used with mtrentw the Caleffi flow meters and liked them. We did up size them to protect against flow loss, called CV.

I am not sure how the 26/99s are mounted reading your post but the correct mounting configurations are in the I/O manuals and I am sure they are on their web site. The issue is not about where the water goes as much as how the motor is pointed. They should be able to handle the system.

I know how to size pumps and therefor think the push/pull systems and flow centers became industry practice because of an inability to do the math or read a pump curve. The circulators are not really pumps. They are designed to move water within a closed system not suck water out of a pond.

I tend to agree with your submersible idea. I would start with what you have first. If you are re-piping you might run the pumps in parallel rather than push pull.

Let me know if you need more.

Mark

 

If you are just looking at 1" pipe, 280 ft total, with 16 elbows, you are looking at 27.8 ft of PD at 8 gpm, and 16.9 ft at 6 gpm, which should be your minimum flow. 1" line should be fine for the 6-8 gpm but you have some other flow restrictions. Now you have to add the 10 ft of water pressure, unless you return the water underneath the pond water's surface. Are you doing this or is the water just being discharged onto the surface? Other than that a single 26-99 should be able to handle 8 gpm at 28 ft/hd, so again, something else is obstructing.
Part of your problem is that at 3 gpm total flow and EWT around 40F you exiting water had to be way below freezing, so I bet your coil keeps freezing, not immediately, but gradually, ice forms on the pipe walls, reducing your lumen when you measure the flow.

 

docjenser - So is what you're saying that as long as I can find a way to maintain the 6 GPM that I'm getting with this temporary setup I should be fine? We got down to freezing last night and the house was cozy warm at 5.75 GPM. I've measured the pond at -20C and still got 40F in the pond. I'm confident that the pond is very consistent with underwater temperatures.

I just have to find a way to get those two Grundfos pumps to get to 6 GPM or wire a submersible in to the pond. I don't know how to go about checking for other obstructions. Is there some way to "snake out" 1" water pipe to try and clear unseen obstructions, like they would for a plumbing line or am I barking up the wrong tree?

 

Lets say your heat extraction is around 16 KBTU/H with a 2.5 ton heatpump, and you are having 3 gpm flow as you stated before, and you are taking in 40F water, your delta T is 10.67 degrees F, meaning you discharge below 30F water. No wonder your heatpump shuts off. Either your safeties kick in or your coil is frozen.
But you are barking up the wrong tree. You are trying to put enough pumping power behind it to push more water through the pipes. I would design my loopfield to have more flow with lesser pumping power. Buy 4x600ft coils, spread them out a bit on a frame with PVC pipe, sink them, connect them and you have a closed loop. Now with your 1" header line, assuming you have no other restrictions (do you have a motorized valve in the circuit, or does the signal from the HP turn on the (2) 26-99s?) you should have 7 gpm flow with (1) 26-99 and 10 gpm with 2 pumps. And the water still comes in at 39F.

 

Hey Doc.

Long time. Go Bills.

Not being a real engineer, Honda was my hero and some times defacto mentor, I thought about fouling and other types of dirt, slow freezing did not enter my mind. Very possible.

Mark

 

Hi Doc,

I hope you don't mind me shortening your nickname, here, lol. Anyway, so you feel that I'd be better off going with a closed loop configuration? I don't think my pond is big enough for that, actually. At least that's what the installer told me when the system was being "designed" for my site.

In my system the HP controls the 2 Grundfos pumps to turn off and on.

 

which will beg the next question: How big is your pond?

 

"I don't think my pond is big enough for that, actually."

Soooo if it's not big enough for closed loop............

 

Doc, the pond is approximately 100' x 60' and is about 10 feet at it's deepest, at least that's the deepest I've measured in the past, although it gradually gets shallower as it gets to shore on one side as we've landscaped it to be a "natural wetlands" area for wildlife. The pond flows year-round. The water enters from the East end of the pond, collects into the main pond (100'x60') then flows down a 2' wide waterfall to a shallower pond 6' below. The most ice I've ever had on the ponds is about a 4' to 6' perimeter on the coldest days in January or February at approx. -5F.

On the cold days it's like an airstrip, here, with dozens of ducks because everybody else's ponds have long since frozen over.

AMI - So, are you suggesting I try your suggestion you posted earlier in this thread? Forgive me, I'm a little slow on the uptake these days.

 

My thinking is 6 ducks per ton.

If the pond does not freeze then I think it is big enough to handle the heating load for the house. There could be issues with frying fish depending on the cooling load of the house, but probably not an issue.

I have a system here in Ohio with 15 tons worth of loop, (300' of 3/4" per ton) at an average depth of 6' with the deepest part of the pond being 12 to 14 feet. I have measured EWTs at above 40*F with 12" of ice on the pond.

 

I don't know where the perception comes from that ponds need to larger than loopfields. In my climate closed loop slinky loopfield in soil is 100' x 10'/ton, meaning 60' x 100' supports 6 ton. Why would a pond with water stratification, much better moisture content (conductivity!, it is a pond of water for sakes!) support less heat exchange???? An in your case there is even flowing water! I have pulled 10 tons of heat out of smaller ponds, with the EWT not dropping below 36F!

So is your 1" lines plugged up by duck pup?

 

Sorry wasnt trying to be cryptic. If there is not enough pond for opem loop there wouldnt be enough for closeda loop. Btu requirement is the same regardless of loop system.

 

Simply because ponds are colder than the ground in winter and warmer than the ground in summer.

 

Sorry, but this is incorrect. In the winter, the bottom of a pond deeper than 6 ft-8 ft always stays 39F (unless it is really tiny, more like a swimming pool), and being thermally connected to the ground below with the entire footprint of the pond (e.g. highly conductive water). This is much better than pipe. Horizontal ground loops usually are designed to drop down to 30F at the end of the heating season, pond loop EWTs we monitor never drop below 35-38F, even in our climate. This has to do with the unique physical properties of water whereas it has its lowest density at 39 F, not at freezing point. So at the bottom of the pond it will never drop below 39F, unless it is way to tiny for the load.
You are correct that the ponds run higher EWTs in the summer, but cooling is only 10% of the annual energy consumption up here in Western New York versus 90% for heating. That is why we really like pond loops up here, because on the bottom, they stay warm.

 

I understand what you are arguing, but EWT's are not the temperatures we were discussing. Water has convection, yes that is why it works so well.

The ground will still be warmer than the bottom of that pond in winter. Unless we're talking shallow ground. You won't get the warmer EWT's though - that I agree with.

But you also won't get those warmer EWT's when you have a colder, smaller, pond. That was my original point.

In this case, we seem to have good spring flowthrough all year round, so he's lucky.

As an aside, the only way we see the densest water at the bottom of a shallow pond in winter is if it freezes over.

 

May be I missed it, but what else were we discussing? What else matters? If the loop is sized correctly, the EWT will be within 1-2 degrees of the surrounding water on the bottom of the pond.

The ponds we monitor here in Buffalo, New York, run consistently around 35-38F EWT, indicating around 39F at the bottom. Ponds loops are simply surrounded by 39F, highly conductive water, and if sized correctly, the water within will get within 1-2 F of the surrounding water after going through the pipe. All the horizontal ground loops run around 30-32F at the end of the winter.

100' by 60' is a pretty good size pond, the volume is the same as a 100' x 60' loopfield, the conductivity is higher, it is better thermally connected to surrounding soil and thus draws the heat better from it. Your original point was that you generalized and said "Simply because ponds are colder than the ground in winter and warmer than the ground in summer." which is simply not correct. No offense, but how many ponds have you monitored? And how many horizontal loops? And may be you could direct me to the data, study, literature or other pieces of evidence which supports your statements.

Now you are really loosing me. Any water body will always have the densest, heaviest water on the bottom, irrelevant if it is frozen over or not.
It is simply a matter of gravity, and you cannot beat those physics.
Water is unique in its property that it has its highest density not at freeze point but 7F above freeze point. One of the reasons it is crucial for life is that it never goes from liquid to solid stage beyond 4-5 feet thick in larger bodies of water, even the ice on the north pole never gets thicker. 4-5 ft deep it is already above freezing, so it protects and supports life all year around. That means that the bottom of a large body of water is always 39F, wether it is the ocean, a lake... or on the bottom of a 10ft deep 100'x60' pond in heat dominated climate.

 

I for one would really like to see some photos of the near-heat pump piping.

 

Zac,

Here are 5 pics from the mechanical "room" where the HP sits.



The pics where you see the two Grundfos pumps are the back of the HP. What the installer did was bring the inlet pipe through the garage, located just on the other side of the wall from the mechanical area, at the base of the side wall and then through the mechanical area behind the HP, up, over and around the HP to the front of the unit, then back up, over and around the HP, behind the unit, up, make a 90 degree right turn, through a drop over the laundry room, across the side wall/ceiling of the garage, down the wall and out to the pond. Whew, I think I got that right! lol!

Anyway, I hope this sheds a bit of light on the mechanical area.

Thanks.

PS - Sorry about the orientation of some of the photos if they are off. This is just how the forum attachment app posted them.

Thanks again.

 

Just to clarify, the first 3 pics on the above post should be oriented 1 quarter turn to the right, the others are correct.

Thanks