New Home, Hydronic Heating Questions

Ironman

RedNeckRacin said:

@Gordy Should be 4 zones, garage, basement, first floor, second floor, So that should be two temperature zones (slabs vs subfloor). I should have only tile and carpet for the different floor coverings. Slabs will not be covered.

I thought about the ceilings, but the idea of warm floors really appeals to me. Also, I was planning on insulating between the floors anyways to help with noise reduction. I know its more efficient to heat the ceiling but I think the attachment to the floors is more permanent if that makes any sense. I was considering adding extra tubing for the bathrooms and kitchen possibly.



Any thoughts on a storage tank? Positives or negatives?

Adding more tubing in baths is a good practice. Also, if you can vary your spacing so that your get more near the outside walls of any room, that can allow for rugs or carpet in the middle of the room. This method can also be used to compensate for varying loads from room to room and sometimes eliminate the need for different water temp zones. Obviously, it's more difficult to do with staple up than in slab.

As far as indirect tanks go, MOST of the time, the stainless steel ones are preferred. It depends on the condition of your water. There are some places where the glass lined steel tanks hold up better. Talke to a water treatment expert in your area.

Gordy

With a proper design, and control strategy your floors should be neutral to the feel under bare feet.

Warm floors come from an era in radiant floor heating when envelopes had higher loads due to poor r value.

Higher tube density helps drive down water temps to increase mod/con efficiency. It also allows for varying room loads to be same water temps as ironman stated.

Use good quality "extruded omega style plates". Not the beer can loose fitting cheap ones. Conduction is king.

keyote

the floors are not really going to be warm to the touch, maybe on the very coldest days the tile slabs might be a bit, you dont want wood floor surface temp over 84 thats less than body temp, you might actually get a more radiant feel from ceilings that can take hotter water.walls are another option particularly in areas like stairwells where floors and ceilings are tough to find the area to overcome the convection and load
storage tank as in indirect hot water tank is perfect for a modcon and radiant. some have a second heat exchanger or additional taps , or can simply be piped to accommodate solar, this is nice because DHW is actually going to be a bigger energy use than your heating so to get it from the sun is a plus. theres a cost benifit and complexity curve but doing your own work probably makes it well worth while over a modest period of time. theres also the independence angle.

RedNeckRacin

I don't think that Western PA has the climate for much solar benefit except in the summer time. Thats good to hear about the storage tank being a good idea. I have never installed one of these systems so I'm trying to absorb any information that can make things easier to plan out. I really dont mind paying for something as long as its cost is beneficial to the project. I.E. better pumps that are more efficient or longer lasting. From what I have been seeing, my floors will be able to do the majority of the heating, I think that I'm going to put tubing in the walls as well for some additional heat. The bathrooms in particular and the stairwell, and possibly the office since it has an exterior door.

Canucker

@RedNeckRacin Don't forget shoulder seasons where you don't need the full input from your boiler. Solar would work well in that instance, even in PA. Whether it's worth the added expense is up to you.

keyote

Look into evacuated tube solar they actually work quite well in the north east even during the winter Im in NYC, but during the summer you could burn no gas at all.
I too thought radiant ceiling a bit far fetched till i looked into it, I can say on the floor of the house i did i learned the plates are absolutely essential if youre wood floor,do not try to skimp or make your own. The 12" oc spacing is like the 300' loops an absolute maximum not a rule of thumb. the closer you make the loops and shorter the entire loops the cooler the water you can run and the more efficient it will be.Its very difficult to nail hardwood over radiant tubing, its not hard in the field with 12-8 spacing thats easy. Its along the perimeters where the tubes often run parallel to the flooring and you may have 3-4 tubes clustered together because yo are sending one loop to the nearest room another to the room farther on and both have return lines back to the manifold.You should map it all out to the 1/4" figuring the angle of the nails in profile now i managed it and didnt put a nail through the 6 loops through two apts on that floor but as i said after looking into ceilings I will do the next three floors with ceilings except the tile areas and some starwells ill do walls. I think it will actually be easier and cheaper and more maintenance friendly and have greater range.Heres a link gordy turned me on to these sunfoam are the cheapest yet best will work great on ceilings
http://www.sunboardpanel.com/ressources/fichiers/f61c2ef1263d.pdf
Yes you want to use ecm pumps, i used the vt2218 because you want a DT of 10-15 in radiant what i found was that it did work despite warning it would fight the boiler modulation and trigger lock outs, however it did seesaw the boiler modulation without actually locking out, so i have switched it to constant speed mode where it is p[umping that top floor zone and the old cellar baseboard zone which i ganged for now on the upstairs tsat. it pumps them fine on speed one or two at 10 watts or 19 watts respectively, however once i have the other three manifolds installed on their own zone valves i will swap it out for a vr delta p pump that will sense how many and which zones are open and increase or decrease speed accordingly. fortunately the boiler seems capable of maintaining the delta T i want with out a delta T pump.
Another issue regarding pump efficiency is how many pumps, you probably figured out you can use a zone valve to control each manifold and only one pump that will come on whenever any valve opens.But many systems are designed around primary secondary piping arrangments where one pump and pipe loop maintains flow through the boiler and another loop comes off that with a second pump to the system. there are reason its sometimes needed, however i didnt want to have to run two pumps if i could run one and i can tell you the KHN can indeed be piped direct with one pump if done correctly and operate fine even at low flows and temps and one manifold only calling for heat.

keyote

The problem with solar for heating is thats an entirely different tank, you will have an indirect tank for DHW, its essentially a stainless tank with taps that put boiler water through an external [triangle tube] or internal [loch] heat exchanger. the boiler water never directly contacts your potable DHW, now with some indirect DHW tanks you have extra ports to another heat exchanger or the same heat exchanger that solar or heat pumps etc can connect with , you can also configure your pipe outside the indirect to effect the same goal if you tank doesnt have extra ports or an extra HX. But to use the solar for heating the house you [pretty much need another tank dedicated to house heating solar energy and a mixing system. since hot water actually is the larger load and the load required year long and a summer load it makes more sense to put the extra cost and effort into the easier simpler DHW load

SWEI

keyote said:

Look into evacuated tube solar they actually work quite well in the north east even during the winter

So do flat plate collectors, and they're a lot less trouble. Flat plates significantly outperform ET's in mild weather and will even outperform them in cold weather as long as you have a decent emitter system. ET's can deliver 200°F water in 10°F ambient with enough sun, but not very much of it (look at the aperture area when you're comparing collectors, not the size of the collector itself.) They turn into a major liability when the tank hits high limit in hot weather.

keyote

Thanks Swei good infor tech seems to have evolved since i last looked when ETs first came out. Cant a drain out be used for overheat?

SWEI

Drainback is by far the best and most reliable way to deal with overheating in my experience, though not all drainback designs are created equal. Vents or vacuum breakers mounted outdoors eventually fail, sometimes without warning. Closed-loop (lightly pressurized) drainback is nearly maintenance free when properly designed, installed, and commissioned.

hot_rod

It is possible to do a one tank solution. Here is my shop/ office system. This is a 500 gallon LP tank I "adjusted".

Two pipe tank plumbing. Solar drainback, wood boiler input, LP boiler input.

DHW via a flat plate HX, radiant mixed down, cast iron radiators.

It is also the expansion tank for the 600 gallons of system fluid.

Demineralized water, Rhomar hydronic conditioner.

Commercial storage tanks often have large side taps like this also.

RedNeckRacin

WOW @Hotrod That's quite the setup. I don't think I will be fabricating my own pressure vessels just for my general peace of mind. I do think I am leaning towards an indirect hot water tank for my DHW as well as a buffer tank for the radiant. I have been pretty busy with work as of late so I haven't been able to devote much time to my system design and layout. I'm also waiting for a callback from a guy who does a manual J calculation just o verify that my numbers are correct.

In regards to the solar, I think I'm going to pass on this option. I would like to try and keep my system as simple and as reliable as possible since I'll be doing the trouble shooting if something goes awry. I appreciate all the feedback from you fellas so far though! I still think that I'm going to try and keep my lines below the subfloor and use the aluminum plates for heat transfer. Some of the rooms that appear to be marginal on the heat transfer vs the required load I'm going to run some tubing in the walls for additional btu's . I really don't want to raise my doors up 3/4" to all for the boards on top of my sub-floor.

RedNeckRacin

So a little update of the progress so far, I just got my electric hooked up in the house and need to wrap up a couple loose ends...pun intended! So I went to price out some boilers at the local HVAC supply shop and they seemed to think my boiler sizes were very undersized for my home size. After some banter, they put me in touch with a guy who does manual J calcs and will do mine for free if I purchase the boiler from them. Deal! I still haven't heard back from him but I'm not in a big rush. I had some vacation time over Christmas that I spent building stairs and fixing some other issues.

hot_rod

Here is a free, simple to use load clc program if you want to try it. double check the manual J that is being done.

Thanks to US Boiler, the Burnham people.







http://www.usboiler.net/heat-loss-calculator.html

RedNeckRacin

@ hatterasguy ,Well I just wanted a double check on my numbers. If I did it professionally or had someone check them I'd be alot more comfortable with them.

Thanks again HotRod, that calculator seems like it has alot of error in it. I came out with ROUGHLY double what I thought my heatloss should be from the coolcalc website.

Jamie Hall

It's unlikely that the calculator has errors in it. However, it is very likely that the assumptions and approximations underlying both the calculators and the inputs have a very large influence on the results.

hot_rod

Thanks again HotRod, that calculator seems like it has alot of error in it. I came out with ROUGHLY double what I thought my heatloss should be from the coolcalc website.

I have checked that load calc result against several other programs and it came out about the same.
SlantFin has a freebie load calc also at their site.

Make sure you enter data correctly it's just a square footage and delta t calculation. The biggest assumption is the infiltration. unless you do a blower door test, that will just be your best guess. Run the load with a couple infiltration options number to see how it changes the load #

keyote

Loop cad allows a free 30 day trial after which it still works except any changes made will not remain and can not be exported,after its closed, however it is still fully functional when opened. It does not only the heat loss but the cool load in the background but more importantly it allows you to design your loops room by room loop by loop manifold by manifold calculating flow btu surface temp swt head rwt and all the rest in the back ground as you draw. its a really intuitive cad based drawing program that can be mastered in an hour once watch their videos and instructions. It allows you to draw with pre composed wall floor roof window specs etc or customize your own.
Frankly I dont see how you can do a radiant system particularly as an amatuer without the aid of something like this its not as if you have any rule of thumb experience to rough it in. you will need all this engineering data to calculate your pump sizes, pipe sizes, loop lengths, zone BTU loads boiler size under different seasons,your expansion tank, buffer tank indirect tank, sizes, and all sorts of other things youre not yet aware of but will need to start piping, you dont yet understand how one overly long loop might make a pump selection problematic but that making the loop next to it take some of the load fixes it instantly to calculate how a dozen or more parameters interact with each other is really hard to do by long division.

RedNeckRacin

@ keynote, I think i am going to use loopcad, i just wanted to make sure my numbers were good to go before starting the clock. The pump calcs do not scare me. I have a civil engineering degree and I have taken fluid dynamics and a few others that relate pretty directly. If I start with crap I'm going to end up with crap though!

@hotrod, have you ever used the coolcalc.com website to check its accuracy?

hot_rod

RedNeckRacin said:

@ keynote, I think i am going to use loopcad, i just wanted to make sure my numbers were good to go before starting the clock. The pump calcs do not scare me. I have a civil engineering degree and I have taken fluid dynamics and a few others that relate pretty directly. If I start with crap I'm going to end up with crap though!

@hotrod, have you ever used the coolcalc.com website to check its accuracy?

I have not used the coolcalc, does it calculate a load just from aerial images? That is what it looks like from the demo? It must use street views also?

I have used those aerial, pictometry programs, EagleView.com for solar thermal simulations and designs. Pretty wild stuff.

I think all the load calc programs or long forms are based on Manual J. Different software developers put their spin on the way you gather or enter data.

The load calcus specific to hydronics or radiant tend to run lower than a typical forced air load calc program.

For a tight load number you would want the blower door results, and a program that allowed you to "build" custom wall, floor and ceiling assemblies. You would identify your framing, insulation, interior and exterior wall coverings, window quality, etc.

RedNeckRacin

@Hotrod the coolcalc website actually uses the framing and floor, ceiling assemblies and lets you put in your door and window types as well as the insulation values. That is why I assumed it was a pretty good number. Even adding storm doors to my exterior doors dramatically cut down my infiltration numbers. I realize that there has to be assumptions because its a model not real world, so I was just wondering how close it was. I mean honestly if its off by a thousand btu, I'm really not concerned.

hot_rod

Give Harvey Ramer a call and see if he will help with a load and design calc, it could be money well spent. It would be correct and appropriate for you project, and include his experience.

I think you are closing in on it, but designing via www leaves some questions and confusion.

RedNeckRacin

OK so I have started vetting contractors and have met with two so far. Is it a bad idea to try and avoid putting any HVAC equipment in the attic? One contractor said that it would be no big deal to pipe air conditioned air up from the basement, the other really was opposed to it. I would have assumed that a company could easily figure out the pressure differential and plumb accordingly for it? House is 24x40 and 8 foot ceilings.

hot_rod

There is a trend towards insulating the rafters, then the attic becomes conditioned space. That makes it easy to install HVAC in the attic space.

But there are plenty HVAC systems in attics, in the heat and cold

RedNeckRacin

Well that's the thing, I wasn't going to insulate the attic ceiling. I have all of my soffit vented and 100% of the ridgeline is vented. I was actually thinking about installing a thermostat controlled exhaust fan to help keep the temps down in it.

Any good reasons to use the aluminium plates vs the hangers for installing the pex?

hot_rod

RedNeckRacin said:

Well that's the thing, I wasn't going to insulate the attic ceiling. I have all of my soffit vented and 100% of the ridgeline is vented. I was actually thinking about installing a thermostat controlled exhaust fan to help keep the temps down in it.

Any good reasons to use the aluminium plates vs the hangers for installing the pex?

There are various opinions on insulating attic spaces. Around here they have been spray foaming rafter spaces in some homes for about 25 years now., so it has a track record. The space is not ventilated when sealed at the rafters. They also spray right against metal roofs also, my shop is insulated that way.

Transfer plates are the best transfer mechanism. On low load installations systems like Ultra-Fin are another option.

Bare, suspended tube, not a great option in my opinion.

RedNeckRacin

any suggestions on which plates to look closer at?

hot_rod

Radiant Engineering has perfected the best plate with a tight tube fit, and data to back up their performance claims. www.radiantengineering.com

RedNeckRacin

Thanks! I'll let you guys know what the HVAC guys come up with system wise.

Jean-David Beyer

My grandparents had their house heated with steam, and there was a radiator in the garage that they had always turned off. If it were my house, I guess I would have heated it to about 40F. Just enough to melt off the snow and ice from the car overnight.

In my present house, I have no deliberate heat in the garage, but that is where my Weil-McLain Ultra 3 80K BTU/hr boiler and 30 gallon indirect is located. The garage is insulated from the house, but not from the outside. Design day is 14F. Usually, the snow is gone from the car and there is water on the floor. I guess the heat leaked from the boiler and indirect is enough. It is not enough to melt the snow from the garage roof (a good sign).

Jean-David Beyer

I have radiant heat on the ground floor (radiant slab at grade). My house is fairly well insulated, a little leaky, good windows (Marvin).

As far as warm floors go, I seldom get them very warm. When it gets below 10F outside, they get kind-of warm, but most of the time they do not. That is because when it is 50F or more outside, the water temperature delivered to the slab is only 80F. If the outside temperature goes all the way down to 0F, the water temperature delivered to the floor is 130F. On design day, it is 116F. In my opinion, I do not really need warm floors. I want them as cold as possible consistent with heating the house enough. With a mod-con, you want the lowest possible return water temperatures and one way to get that is to supply the lowest possible supply water temperatures.

RedNeckRacin

So i found an HVAC guy, he agrees with my numbers. So I had a question about lubing the aluminium panels and what to secure them up with? He thinks I'm nuts for using them, but I found a great deal on Amazon for the omega shaped panels. I'm thinking garage door lube which dries and leaves a graphite residue or a silicone spray maybe? For securement to the sub-floor, I was thinking 1/2" staples every 6" or so?

hot_rod

If they are the thin gauge type, a pneumatic stapler tends to deform them then you lose floor contact. A screw gun with self tappers works well.

With thin gauge some silicone would help with tube contact, but it is a messy job.

RedNeckRacin

I was thinking a hand stapler, they are the thin gauge.

Well, the shape of the panels do literally snap onto the tubing so they are shaped well. I was thinking more along the lines of lubrication so they can move with thermal expansion.

hot_rod

Two of the problematic concerns with thin gauge flashing type transfer plates.

They tend to "oil can" when they heat and cool. They make that ticking or pop sound that an old style oil can would.

Limiting temperature swings with constant circulation or properly adjusted ODR will help some.

The other is grip, or lack of. It is pretty tough to allow the tube to move without some sort of noise. It will be a creaking sound like when you rub the tube against itself. That is why silicone adhesive was used to try and limit that movement.

The noise issue got so bad that one radiant company started suggesting that you staple only one side of the plate to the floor, let the other side float. A swing and a miss on that concept also.

Then bare suspended tube was presented to the industry as a solution to the plate system noise. Another path in the wrong direction for all but the lowest load requirements.

That is why most of the installers here that have been down these roads are suggesting the heavier gauge, tight grip type transfer plates.

I'd go to a Ultra-fin product before I used thin plates again, there is no easy fix once they start talking to you.

RedNeckRacin

Well for $2.53 a plate for the thin ones versus a local company that wanted almost $9 a plate for the HD ones, I think I'll deal with a little noise and the increase in efficiency?

Harvey Ramer

There has been a lot of radiant installed with the thin plates or staple up, that was later ripped down and reinstalled with heavy gauge plates. That is not a fun job. I would urge you, as would every other professional on here, to use the heavy gauge plates.

A radiant system is a premium heating system. You can't get premium performance out of it "on the cheaps".

Gordy

There is a reason they cost that much.

Paul48

http://www.ultra-fin.com/
There is a lot of good information on that site re: noise. It depends a lot on tubing choice. Have a look.

hot_rod

RedNeckRacin said:

Well for $2.53 a plate for the thin ones versus a local company that wanted almost $9 a plate for the HD ones, I think I'll deal with a little noise and the increase in efficiency?

If it were just a little noise there would not be extruded plates on the market and in all the major radiant manufacturers catalogs No one would spend money on aluminum if it didn't have any value.

Hard to predict how much noise or what your families tolerance is for noise in the middle of the night, but...

Where the thin plates still have some value is sandwiched between layers of subfloor. That way the plate cannot distort, and the tube is locked in at both ends so expansion and lateral tube movement is eliminate. Not unlike pex cast in concrete, in that respect.