Ontario Electrical Usage for Waterfurnace Premier Seems Way Too High

And as I am going to call in the furnace technician, I would like to explore the option of changing the circulation pumps from the 26-116's to 26-99's for less electrical load. Also have them change the wiring to those pumps from the current setup (which seems to be both pumps on for Stage 1 and Stage 2, (contrary to what the Waterfurnace Installation Manual shows which is 1 pump for Stage 1, 2 pumps running for Stage 2).

Earlier (2-3 weeks ago) I measured flows and came up with between 11-12 gpm which people here thought low. And that would have been with the 2 99-116's running, though earlier this week while the pumps were still working, I listened in with a stethoscope and thought that possibly only one pump was running (based on perceived volume of the noises heard between the two pumps. So is there risk by changing the pumps as I am contemplating, and changing their setup so one pump runs in 1st stage instead of currnetly 2 pumps, that I make things less efficient?

 

Mr Xtech:

I believe the problem occurred coincidentally before I fuddled around with taking measurements inside the unit, which I did on the morning of December 28. Electrical usage in the house that night starting after midnight or so skyrocketed to between 5 to 9 kW/hour. Normally electrical draw with Stage 1 heat on continuously is 3.5 kW/hr (includes normal house load with nothing turned on at ~0.3 kW/hr). Nights previous when Stage 2 kicked in for short periods (similar to patternn in the Ecobee screen capture), power use would increase between to between 4 and 5 kW/hour .

 

I looked at your Owners Manual Table for flow based on loop inlet vs outlet and they were low a few weeks back.

Hopefully the technician will have some idea as to whether going with smaller pumps, 26-99s would be wise.

I have the 3 speed 26-99s which allows me to put them in slow speed for cooling season.

If you let the Technician know you might have a fuse issue, he could save time not having to start from knowing nothing about what has happened.

I would get the unit up and running now and change the pumps when its warmer outside.

 

I'm talking about the lock out of your compressor on Low Pressure and Low Temperature in the loop.

That was new and is an indication your pumps were not running. It's also possible One pump has been running only, and with the increased need for heat, the Unit finally exceeded the tow lockout trip setpoints due to one pump only. No pumps due to a blown fuse would definitely give you the lock outs.

 

11.9 gpm does not cause a low pressure lockout. Plus now that the loop has rested for a couple days, the unit would start up again if your theory is correct, which I question.

Andrew,
Now, your heat extraction is a bit low and your COP is also a bit low from the numbers you gave us in December, I interpreted that as a measuring error due to the fact that you also had 11 gpm in first and 11.9 gpm in second, however you had the same pumping power behind it.

One thing you could do is directly run a wire from your breaker box to the one of the pumps and wire them directly, then you know if one or two is running at 11.9 gpm.

It will also get you heat back on temporarily until a tech arrives. The 26-116 has only 10% more ft/hd, but uses almost 70% more energy than a 26-99, you will not see a significant change in your flow, which is the whole point why I question the purpose of 26-116 pumps in geo application.
Definitely, if you can get the 3 speed pumps, use those, since you might be able to further reduce your pumping power. Seems like you might have to get a new pump anyway.
The should also be wired for 1st and second stage operation. You might loose 20 watts of compressor efficiency due to lower flow, but you gain 350 watts in pumping efficiency.

 

Would my 12-13 year old waterfurnace system (I assume using 2001 technology since the manual date is January 2001) be smart enough to use a 3-speed pump? i.e. take advantage of the various speeds which presumably would also use variable levels of power? Or would a single speed version be sufficient, and I assume a bit less expensive? Cost of the pumps is not the driving factor here as I'd expect the price difference would not be too much, just if my system simply sends an on-off signal to the pump(s), then I don'tsee what the 3-speed offers me.

 

You set the speed on the pumps manually, you have 3 stages. You might be able to dial them down further, but that depends on the pressure drop of your entire system. Price is pretty much the same. they would still turn off/on, just at the preset speed. There is really no downside.

 

Test the fuse in the case with the multi-meter.

 

When your pumps are returned to the scheme in your schematic, will start one pump in Stage 1 and the 2nd Pump in Stage 2.
You would have to set the Hi Med Low Speed for the season you are in such as cooling season vs heating season. The pumps use a manual selector switch on the outside of the termination cover.

Here is a New 26-99 on ebay, 220 vac 3 speed:

http://www.ebay.com/itm/Grundfos-23...820218?hash=item41badb7aba:g:wAEAAMXQVERS1slH

Here is a list of 26-99F 's. Make sure they are 220vac and match your current method of hookup in the flow center/ loop, setup which should be by flange.

The average price is $250 each.

 

Not sure I follow you here. Why would a 3 ton system need different flow in cooling versus heating? And why would a customer have to change the setting seasonally?

 

Doc,
On my Trane 4 Ton I can turn down the flow to Low Speed in the summer and cool the house since it's relatively cool in the summer. The Unit does the job intended with no lockouts and saves me money on pump power. The loop temperature doesn't get too hot as it would in the South where Cooling places the larger demand on a Geothermal Unit. I realize the hotter the loop gets the faster the heat would flow into the earth, but this is based on the type of soil and factors that I don't have available in my owners manual, except the hotter the loop water the less efficient the Heat Pump will be when cooling.

In the Winter my Unit struggles to keep the house warm, so I turn up the flow to maximum in order to draw us much energy out of the increased volume flow rate of water as possible. The differential loop temperature across the unit becomes less and return water isn't as cold as it would have been if I used the lower flow.

The tables that come with the Unit show that as flow increases, the efficiency of the Unit increases. Also the waters ability to pick up heat from the earth due to more mixing of the laminar layer of the PE Pipe. The loop water temperature remains higher in the Heating mode which also increases Unit efficiency per the Tables in the manual.

As you know Heating during the Winter up North is what the Geothermal Unit should be sized for since that's when the demand on the Geothermal Unit is greatest.

 

Hi. I'd like to say thanks to all who have provided me with advice and I'd also like to wish you a Happy New Year

 

Andrew,
Happy New Year to You and Yours.

 

Apparently there will continue to be in 2017 a vast number of features, characteristics, thermodynamic properties and laws of physics applicable to geo HVAC systems known by Mr Wrecks Tech but not known by the several veteran installing contractors who frequent this site.

The trouble with Rex is that he has evidently stayed at Holiday Inn Express hotels just often enough to be dangerous. That's somewhat like knowing "a little bit" about brain surgery and then picking up a scalpel. Some examples from the above post alone:

1) "the hotter the loop water the less efficient the Heat Pump will be when cooling" Maybe, but maybe not. It is easy and unfortunately quite common for improperly designed, installed, and commissioned systems to consume excess energy in pumping power that is NOT recovered in compressor energy savings. Understanding the relationship between pumping power, compressor power, and overall system efficiency is crucial to a successful system.

2) "Heating during the Winter up North is what the Geothermal Unit should be sized for" Wrong, for at least 3 reasons:

a) Total life cycle cost of ownership is nearly always lower in heating-dominant climates when system is sized for some use of auxiliary heat
b) Oversized cooling systems sacrifice both efficiency and comfort
c) Mechanical and energy conservation codes prohibit heat pumps from being oversized in cooling mode.

d) What's Up with All the Random CaPiTalIzAtIon?

3) "Also the waters ability to pick up heat from the earth due to more mixing of the laminar layer of the PE Pipe"...The PE pipe (actually HPDE ) doesn't have "layers". The fluid flowing within it is subject to lower heat transfer to / from the wall of the pipe when fluid velocity is reduced...laminar vs turbulent flow.

Those who believe that little or no heat transfer occurs absent turbulent flow are hereby invited to slowly immerse a hand into a sink or tub of 120*F water and then report whether any heat transfer occurred from the water to their hand.

4) Rex does a heckuva lot of remote diagnostic hypothesizing unencumbered by facts, unequipped with years of service technician experience, and uninformed by specific data (pressures, temperatures, currents, flows, voltages, etc) required for accurate, competent and reliable troubleshooting.

The title "Forum Leader" imperils credibility of geoexchange.org.

 

Oh boy....You got a lot to learn here....I am just replying so no one takes your comments here for granted!

I am a big fan on reducing pumping power, since it significantly can effect system COP or EER, with only minimal higher wattage used by the compressor. But what of what you are expressing above has anything to do with reducing the pumping power in the summer only?

A units capacity does not significantly change due to the water flow. A dual stage 4 ton Trane in second stage at 30F EWT and 1350 cfm has a heating capacity of 35.1 KBTU/h with 9 gpm, and 35.6 KBTU/h with 12 gpm. Do you really think you could tell the difference? So your delta T goes up by 1.5F, and your average water temp in the coil is 0.75F higher. Do you think it makes a difference?

Sure more turbulent flow might help slightly for heat transfer, so does efficiency, but by how much, and at what (pumping) price? Loop temps will not change with higher flow rates. While it is a whole different debate how units should be designed in heating dominated climate, may I remind you on your original comment:

"You would have to set the Hi Med Low Speed for the season you are in such as cooling season vs heating season."

No, nobody has to do that. Nor has any of your reasoning and off topic going anything to do with the question. If you want to reduce your pumping power since you feel that your unit is only running in 1st stage in cooling due to lesser loads, and you want to run it at a higher flow rate in the winter due to second stage running more often, yes you can do that. But I would argue that you have any noticeable benefits from it, you might as well keep it at the lower pumping setting for the winter. So what is your actual flow in the higher or lower pumping setting, and what is your reynolds number for turbulent flow in your loop circuits?

Keep on thing in mind, heat extraction is defined by: delta T x flow x 485

Nothing else.

Heat capacity at a certain EWT is coming from the compressor size and the heat exchanger size.
The only impact the source flow rate has is the impact on the average water temp inside the heat exchanger.

 

Doc:

I am looking at the Grundfos pump curves from their literature. Recall that my pressure drop measured in early-mid December indicated flows between 11 - 12 gpm (subject to possible erroneous reading as you have pointed out). If only 1 of my 26-116 pumps was working that implies head loss of between 28 and 29 feet. If both were working then head loss is 56-58 feet. This is based on the pump curves shown in my Flow Centre manual (attached figure). Something to note, my loop being a lake loop, is the the lake surface is located 5.0 m (16.5 feet) below the basement floor of the cottage (surveyed by me). Does that height differential, and perhaps more (becaase the loop is submerged, and therefore lower still) get added into the head loss calculation because the fluid has to be lifted 16.5 feet or more? (the circulation lines also run along the basement ceiling joists, so does that extra eight also get considered?)

If I were to specify replacing with 26-99's then am I setting myself up for disappointment? I have attached pump curves for the 1 speed and 3 speed versions of the 26-99 pumps. Assuming 28-29 feet of head, then it looks like these pumps would be able to make 7-8 gpm (1 speed version) or 3-4 gpm (3 speed version). Maybe I better stick with the 116's for now and wait until I can confirm head losses through additional readings after we get the geo working again.

 

Andrew,
Back when I was designing my loop, I ran into information that said head due to height doesn't count in a closed system since the water going into the loop flows down hill in the loop and pushes the water flowing up the hill reducing the head loss due to height.

If that's true the head loss will be from the friction of the pipe and pump losses.

My loop flows down into a valley with a total drop of over 100 feet. my 26-99s in slow speed will pump the water with no flow problems with the Geothermal.

If your head loss theory is correct, my pumps wouldn't be able to move the water in my loop due to the huge height differential thus head loss.

My loop is 2000 feet of 1.5 inch ID PE Pipe.

 

You are getting the pressure drop science a bit wrong.

1) vertical difference in a closed system even each other out, otherwise a 400ft borehole would be difficult to pump. Thus only the pipe resistance matters
2) you measured 9 PSI at your heatpump indicating about 12.1 gpm at around 33F EWT. That means your flow rate is 12.1 in the system.
3) given the 26-116 pump curve, and assuming that only 1 pump is running (otherwise your loop field pressure drop would be really badly screwed up) you have about 27ft/hd at around 12 gpm
3) The same system would have a pressure drop of 24.7 ft/hd at 11.5 gpm, which is right where a 26-99 would be. In other words replacing a 26-116 by a 26-99 would only cost you 0.5 gpm but cost you 65% lesser pumping energy. Did I say before that using 26-116 makes no sense in geo systems....???
4) (2) 26-99 in series at medium speed would get 13.6 gpm at 34.7 ft/hd, and would consume around 300 watts. But you could always bump them higher.

 

Update:

Furnace technicians were out to the place on Thursday:

1. Fuses were fine
2. Geothermal was working (after they reset the fault code)
3. Both circulator pumps were working, drawing 1.34A each (their rated amps are 1.75A each)
4. Flow in system with both pumps running was 12 GPM.
   
   • Based on pump performance curves in the flow center manual, both pumps running with 12 GPM flow = 56 feet head loss in piping! (if amperage = 75% of rated amps on units, does that make a difference to this head loss value?)
5. EWT = 33.8F, LWT = 27.4F
6. Stuck around for a couple of hours monitoring, noted loop temps dropping 0.3F/hour
   
7. Believes there may be a mixture of methanol and ethanol in the loop

The furnace contractor called me yesterday and we spoke about what is causing this. He's not certain but thinks the loop temps are declining over time with continuous use and that eventually gets down to the 15F trigger temperature on the unit (I note from my Ecobee tracking that furnace can be running continuously without stopping when it is colder out, Stage 1 mainly but as temps drop, frequent calls to Stage 2, then back down to Stage 1). Only way to be certain would be to continuously log temperatures.

He also thinks that if the system (which we inherited with the cottage) has a mix of ethanol-methanol in the loop that this could affect its efficiency and lead to crystallizing of the mixture. He says that they have two common tests they can use to check loop fluids. Hydrometer, and his hydrometer reading based on ethanol gave 28%. And something else, a burn test of some sort (?), which I understood suggested methanol in the loop to some unknown concentration. He indicated that 99% of systems up here use ethanol instead of methanol.

I am not sure I buy into the mix of two alcohols being a bad thing, certainly not causing the freeze point to change significantly. I would think that if there was a mix, then the freeze point would be a weighted average of the individual freeze points for the mixture, and not some higher temperature. But contractor seems to think having potentially ethanol and methanol in the loop is a bad thing. Is it?

Other possibility, which seems more likely to me, is the lake loops are undersized, and over time are not capable of keeping up with the transfer of heat, thus temperatures in the loop get colder and colder over time leading to the lockout.

His suggestions are:

1. Monitor temperatures of the system - some form of datalogger is best over spot temperatures
2. If this happens again (and as a pessimist, I see no reason why it won't happen again soon if it has already done so once already early-ish in the heating system) is to remove all the coolant, and replace with ethanol/water mix at known concentration
3. In summer, float the loops and check them over, looking for kinks in the piping, confirming their length, etc.

I don't know what to do at this point. Wife is making comments about just giving up and installing propane furnace and tank.

 

The number match better now. You have 37,248 heat extraction from the water, so your unit is healthy. Take it as good news.

Knowing now that both pumps are running, they obviously work against a lot of back pressure, otherwise they would have more amp drawn, and more flow.

By definition, unless it is too short or not deep, your loop cannot drop to 15F leaving temp in the loop if surrounded by water. If ice starts to form on the outside of the loop, then your temp will drop quickly. So the problem is not the antifreeze in the loop, but that the loop in a lake might not be deep enough to take advantage of loop stratification, but exposed to water barely above the freeze point. Now you float 25F water through the pipes, the water on the outside drops below freeze point and ice will form. Then you have very impaired heat exchanged, loops will get cold quickly, and more ice will form. A vicious cycle. That's why geo in lakes or rivers does not work well, or does not work at all.
Do you have any info about your loop? Length, pipe diameter, number circuits?

To get to the bottom of this, you need to accurately monitor your loop temperature.