Using 0018e to balance system?

AlaskaDick

I'm designing an in-floor radiant systems for my own house and will be adding "staple up" tubing with heat transfer plates in a crawl space. There is considerable difference in the head loss in each of the six or seven zones so I plan to use balancing valves. It struck me that the substantial cost of balancing valves is not because they are able to restrict the flow, but because of their ability to measure the flow. However, the need to measure a zone's flow and balance it to the rest of the system should only be needed when the system is commissioned or modified.

If I understand the capacities of the 0018e to accurately control head pressure and measure flow, couldn't one be used in conjunction with globe valves as an alternative to balancing valves?

I would shut off all but the zone under test and use the globe valve in that one to set the desired flow as measured by the circulator. For zones where the minimum flow rate of the circulator is reached I would add a large zone and set the flow based on the difference between the already known flow of the large zone and flow of the smaller zone. If this will work, the savings on balancing valves will easily pay for the circulator.

Derheatmeister

Great Idea...But,I do not think that these circulating pumps can measure that accurataly.

hot_rod

What about a manifold with flowmeters built on. Those should get you within a 1/2 gpm or so accurately. The valve built into the manifold are balance friendly.

With a manual balance valve, every time you make a change on any valve, you need to go back and re-balance the others. So globe valve balancing would be fairly time intensive.

Unless the pump has a flow meter of some sort built in, I think it calculates GPM by the change in rpm.

If you know the exact GPM each zone manifold needs, add a PIC pressure independent control valve at the manifold. The PIC is a dynamic balance valve, once sized it keeps the manifold flow at that setting.
Then adjust every loop with the manifold flowmeter. The PIC keeps the manifold at the required gpm, always, works great with delta P circs. That should get you as close as you realistically can get. Above and beyond what most installers do to balance systems.

Some info on how PI pressure independent valves work.

AlaskaDick

Thanks for the responses.

Hot Rod - A manifold with built-in flow meters would certainly work, but I've locked myself into using a couple of 8-port valveless manifolds along with zone valves at the manifold. I've bought them and figured out how to fit them into a fairly compact space next to the new boiler. I haven't yet bought balancing valves and I'm hoping I don't have to. The overall system will be similar to the schematic in your third screen shot. If I can use globe valves for balancing they will be in place of the balancing valves shown.

I'm still on a steep learning curve, but my understanding is that if I can accurately regulate the pressure to a zone and can accurately measure the GPM flow, I should be able to set a desired flow by varying the head loss. It could be with a balancing valve, globe valve, or any other restriction that can be finely controlled. Once set, the flow rate through the zone should stay the same until something in that zone changes or the circulator head changes. (I'm intentionally ignoring temperature changes as that should affect all zones.) If each of the zones is set independently but at the same head, the individual zones should always flow at the set rate if the circulator is able to maintain the pressure differential between the delivery and return manifolds as the zone valves open and close and there also shouldn't be a need to go through multiple iterations to set flow through the zones.

For this to work, I had to make a couple of assumptions.

- The head of the constant pressure circulator can be set through the Bluetooth ap at a specific value and will not vary significantly for changes in head loss as zone valves open and close.

- The circulator through the Bluetooth ap can accurately display the flow. (It may just be marketing hype, but on the videos showing the Bluetooth ap for the 0018E both head and GPM are given to the one hundredth of a foot/gallon. I suspect that an accuracy of only 1/10 of that would still be adequate for zone balancing.)

-Even if the GPM read out is only proportionally accurate when pumping into different head losses rather than absolutely accurate it should be adequate for balancing purposes.

I think what I understand about the circulator is that it senses pumping resistance/power consumption and uses that along with the pump speed to develop numbers for GPM and flow via some form of electronic wizardry.

By the way, I really appreciate the time and effort you and the other industry trainers spend on this web site, Idronics, and Youtube videos. I've probably spent a couple of hundreds hours soaking up knowledge from them and Siegenthaler's book.

hot_rod

What is the range of gpm you are working with? A standard flat disc globe valve is a tad bit better than a ball valve, mainly the wheeled handle allows for better control. A better globe design has a tapered plug, better authority. But you still need an accurate way to read what you have.

Here is an example of 3 readings from my shop test wall.

The Quicksetter at just over 6 gpm, the BTU meter 5.4, and the Alpha readout 6.1. It does indicate "estimated" flow on the GO ap. So I'm not sure what the definition of "accuracy" is. I've found various pump readouts to be off by 30% or more. The pumps with the vortex flow devices seem more accurate than the calculated method.

Uponor had those flow readers that you clamped a meter around, like an Amprobe. I recall those being un-reliable also.

Thanks for the shout out on the Idronics

AlaskaDick

Hot Rod, per your attachments, you found the biggest flaw in my plan. Flat faced globe valves are a poor choice for regulation and it appears that the proportional valves are somewhat specialized (which equals higher cost). I took a valve apart and it looks like one could modify a flat valve with a new stem and plug or even just machine a replacement for the flat washer with one of the correct shape for regulation. However, I don't think I want to do prototyping on a heating system in a location with a -20 design temperature. The restriction to flow inherent to globe valves could also be an issue.

Your photos of your test wall are interesting. That's a lot of variation. I'm assuming they were all for the same conditions on the same circuit?

As for GPM I'm still working through room heat loss calculations and specific boundaries for each zone. The original owner built my house in four phases in the early 1960s with the first two being from surplus WWII buildings moved from a local military base. (When I tore into some of the walls to remodel I found only 2" of fiberglass insulation . . . in Anchorage, Alaska.) He added a garage, then converted that to living space and built a larger garage. It was cold, drafty, and under-insulated.

After a couple of waves of remodeling and energy improvements about 2/3 of the house is above R40 in the ceiling, about R13 in the walls with sprayed in foam, and the crawl space walls are insulated inside and out with extruded polystyrene foam. The shop and garage have about R30 in the flat roof's ceiling and about R35 in the walls with fiberglass and 4" of exterior expanded polystyrene foam. The shop floor is slab on grade, no insulation, and the garage has radiant heat in the floor with 2" of extruded polystyrene foam under the floor. With all of these variations in construction the room-by-room heat loss calculations are taking some time.

Square footage for the proposed zones will vary between 334 for living room and 300 for the kitchen. These two will probably be combined. Bedrooms are about 224, 156, and 101 SF. A unheated 47 SF entry which currently gets its heat from adjacent rooms will probably either have a section of radiant wall or a panel radiator. The shop has a unit heater but almost all of its heat comes from waste heat from the utility room. I am also working on adding a booster coil to temper the HRV delivery air from the dedicated ducts. On sub-zero days it can get into the 50s. The last two zones, and possibly two bathrooms will use TRVs.

I just noticed the topic in the most recently published Idronics (#34) is "The Evolution of Hydronic Balancing." Time for more reading.

Dave H_2

@AlaskaDick . What you are describing on doing would definitely work as you describe with the 0018e and balancing the system as long as you are using a balancing valve that is not going to change flow and other zones are opening and closing.
That has always been one of the things that drove me nuts on jobsites was trying to "balance" radiant manifolds. As you adjusted the flow in one loop, it changed the flow in others especially when there were fixed speed circs being used.
With circs like the 0018e, it allows you to fine tune the system based upon operation. My suggestion is get kinda close, you'll sleep better!

Mad Dog_2

Sage advice from the Sharpest men in the Business...Mad Dog 

AlaskaDick

Dave H_2 and Hot Rod, thanks again for the comments.

I wrote a detailed comment and then lost it. Trying again.

At first, the flat plug on the generally available globe valves looked like a deal breaker. However, I took one apart and it looks like the valve can be easily modified to get proportional opening by replacing the washer with one of an appropriate plastic that has the proper profile or adding a dome of the proper profile on top of the washer. (I have a lathe, milling machine, etc., in my home shop). Another issue may be the high head loss inherent with a globe valve. I'll have to check the numbers when I know what my flow rates need to be.

Your experience with the accuracy of the numbers displayed on the circulator in your test wall is interesting and concerning. Thanks for sharing those photos. The manufacturer's videos suggest that flow and head measurements from the circulator should be more accurate.

I haven't come up with zone flow numbers for my house yet, I'm still working on getting good heat loss numbers and determining what part of the floor isn't suitable for running the PEX (cabinets, closets, etc.). It is a bit of a challenge to develop the room heat losses as the three sections of the house have different levels of insulation and types of floor. It includes a well insulated crawl space for the main house, shop with uninsulated slab on grade, and garage with 2" of foam under the concrete floor and radiant heat. Ceiling insulation in different areas is R40 or R25 and walls are R13 and R35. Various improvements I've done over the past 22 years have brought the house to a 5-star energy rating. I'm working on the room by room heat loss calculations, but it is taking some time to make sure I'm putting in all the correct data.

The square footage gives an idea of the differences between the needed flow rates. The largest under floor radiant zones will be 334 SF living room and and 300 SF kitchen, which I may combine into a single zone. Bedrooms and an office are 224 SF, 156 SF, and 101 SF. The garage that already has radiant heat is 576 SF. The shop is 418 SF. It has a unit heater which rarely comes on and it is mostly heated by waste heat from the utility room. An entry way that currently gets its heat from adjacent rooms is 47 SF and frequently cold. I can't get under the floor so plan on using either a section of radiant wall or a panel radiator and TRV. I am also working on a booster coil for the air delivery from the HRV - it air gets down to the 50s in the coldest weather. It will be controlled by a TRV with the sensor in the duct. A 63 SF laundry room is surrounded by conditioned space and won't be heated as it has always stayed warm without added heat. I'm in Anchorage, Alaska and I'm using a design temperature of -21.

Derheatmeister

Dave H_2 said:

@AlaskaDick . What you are describing on doing would definitely work as you describe with the 0018e and balancing the system as long as you are using a balancing valve that is not going to change flow and other zones are opening and closing.
That has always been one of the things that drove me nuts on jobsites was trying to "balance" radiant manifolds. As you adjusted the flow in one loop, it changed the flow in others especially when there were fixed speed circs being used.
With circs like the 0018e, it allows you to fine tune the system based upon operation. My suggestion is get kinda close, you'll sleep better!

Hello Dave H ...Can you elaborate on how accurite the flow displayed on the 0018e is vs. measuring it with a good Flowmeter.
Personally i have seen large discrepancies.

Dave H_2

@Derheatmeister, original circs with a flow reading used to have a +/- of about 30%. I had an early one many years ago in my house when I was working for a pex company and it heated it for 4 years on 0.0 gpm!
Today, the numbers are closer, the math is better. Again it is still a calculation based upon several factors since none of the circs have built-in flow meters. From my guys they tell me it is about +/- 10%

hot_rod

In Idronics 8 we show an example of final balance at the manifold. When you start looking at small loop lengths the flow rates are so small I doubt you will read flows under 2 gpm with any real accuracy. Certainly not a flow of .202 gpm Doubtful with the circulator readout.

The flow meters on the manifolds will not read low flow accurately, even . 5 gpm.
If you can find a manifold that actually has balancing valves, tapered plug type valve, you could dial in really close. Caleffi no longer offers the true balance valve manifold, no one really took the time to dial them in anyways.

Be realistic on how accurately you will be able to dial in flows.

AlaskaDick

I sent an email to Taco's tech support asking what level of accuracy I should expect. The response was that these are calculated values based on power used by the pump. Accurate to 5-10%.

A circulator with this amount of inaccuracy may still be usable for balancing if the readings are consistent and proportional across the range. For balancing, the relative flows should be what is important, not the absolute flows.

Thanks for all of the responses. This has been an interesting exercise. Knowing the strengths and shortcomings of the numbers displayed by the circulator is helpful.

AlaskaDick

Another thought, would measurement of the fluid return temperatures have a value in balancing? Particularly when a manifold is used for several circuits in the same zone?

hot_rod

This issue is a good read for understanding how heat transfer works
The return temperature will change based on  the load at any given time

AlaskaDick

Hotrod, I read the Idronics 23. Thanks.

Another balancing question - I am looking at up to seven zones using zone valves with a single constant delta P system circulator. I will also have about three very small zones where I think TRVs are a better choice. Is there any reason to use balancing valves on the zones controlled by a TRV?