New Radiant Heat install initial startup

styxplo

I have a 60 X 40 pole barn with 12' high ceilings with open rafters. I have steel panels to eventually put up as a ceiling and plan on blowing in insulation in the future along with vinyl face roll pole barn insulation on the walls. I used loop cad to help figure out the design. I used 70 degrees as my design temp, but only intend to keep it at 45-50 degrees. I have 11 circuits of 1/2" pex each roughly 280' in length spaced at 9". I used 2" foam insulation under the entire barn floor with 1" around the perimeter as a thermal break. There is a mix of 60% distilled water and 40% antifreeze. The concrete is 6" thick and unfortunately the pex is zip tied to wire mesh at the bottom of the pour. I did this at the advice of the concrete guy years ago not knowing it would have been better closer to the top of the concrete. I purchased a ready made panel with a primary/secondary loop and a boiler pump and system pump. I have a 120,000 BTU mod/con boiler with a 10:1 turn down. The boiler output temp is set to 140 and that is what the thermometer is reading on the hot side of the panel. The water temp going back to the boiler is about 84 degrees. The flow going through the boiler is 2.7 GPM. The water temp on the hot side of the manifold is about 109 degrees and the return is 80 degrees. All of the manifold flow meters (11 of them) say 0.7 GPM. The thermostat is embedded in the concrete and set to 77 degrees which is keeping the barn right around 52 degrees. LoopCad says my required water temp is 128 degrees and my required surface temp is 85 degrees to keep the barn at 70. A couple questions. 1: how long should I expect the concrete to take to initially heat up. I imagine there is a point where it just keeps it at a temp rather then initially bringing it up to temp. 2: The boiler doesn't have any indicator to say how hard it is actually working when its on. (is it at 100 % fire or 10%) As of now it is able to keep the output water at 140 degrees. 3: I turned both pumps up to high speed thinking this will increase my heat output. I keep thinking about it and I'm not sure what affect or how to figure out which speed setting is best/most efficient. 4: The outside temperature has roughly been in the 20's-30's (Youngstown, Ohio) since I fired it up. The boiler seems to be on a lot more then its off in an hour and we are no where near the cold winter temperatures we are going to have most of the winter. I'm trying to determine how efficient its going to be and how much energy its actually using without knowing how hard the boiler is firing 5: Is there anything that stands out that doesn't seem correct? Sorry for the long winded message, but I tried to cover everything....Thanks Mark

DZoro

It will take quite some time to settle in. 140 is too hot, go down to at least 120*. If your load calc said 128* at design load then that would be your maximum water temp on the coldest day of the year. Slab heating is slow and steady, don't rush the results.
D

GroundUp

Your noted flow and temp drop say 75,600 BTU across the boiler but 111,650 through the floor- the latter would be running wide open at 93% efficiency. This sounds much like a Menards install with a Hydro Smart "boiler", and about par for the course. It should have taken about 18-24 hours to thoroughly heat up the slab from cold, but if your return temp is 80 the slab is already warm. Ideally, the boiler would run 24/7 at whatever firing rate is necessary to maintain slab temp so it's probably not a big deal that it runs a lot if it's being modulated- which is not evidenced by your noted temps. Are you sure those are regular temps now that the slab is up to temp? Your 1" thermal break isn't doing you a huge favor, it should have been 2"+ but is obviously much better than nothing. Which antifreeze did you use? If more Menards product, the Cryotek -100 is only a 55% concentration out of the bucket so at a 60/40 dilution you'd be down around a 20% concentration now.

styxplo

I gradually increased the boiler temp to 140 from 120 to get the temperature in the barn to steady out at around 50-52 degrees. It has been on now for about 6 days. Set below 140 it couldn’t maintain the 50 degrees. I came up with the same 76500 and 111650 which I don’t understand. How can the btu through the floor be more then the boiler is producing? It is in fact a hydrosmart setup. I wasn’t sure I was allowed to call that out. Im curious how these numbers gave you enough clues to figure out my set up? And the “ boiler” in quotes with the par for course has me a little worried!!! Also from my numbers you stated it’s probably not modulating and is WFO. I’m worried that this is my case and I’m going to have some expensive gas bill ( I just got the gas line run and this is the first appliance running on it) I lowered the set point to 130 on the boiler earlier today but the outside temperature was in the low 50’s today so it was off most of the day. But yes I believe those numbers were the regular temps with the slab up to temp. Right now I’m at 129 and 81 on the boiler and 100 and 80 on the manifold. I guess the big picture is am I good or is there something else/ more I need to do. Is this going to be an energy hog?? The antifreeze is cryo-trek -100 and on the back of the bucket stated that a 50/50 ratio gives me burst protection down to -20? Im thinking I am actually closer to a 50/50. I used 15 gallons of cryo-tek and about 16-1/2 gallons of water. I really appreciate the help and this is a learning experience. I am goin to be putting together a system for my house in the very near future and I am goin to start a new thread. Thanks again Mark

DZoro

What thermostat are you using? I would recommend a slab sensing stat. Does that boiler have ODR control capability?
Don't know what your weather is like there but, warm days and cold nights this time of year can really mess with radiant floor systems. Best to keep the slab at a constant temperature at the current outdoor design water temp required at any given day/time/temperature.
D

Zman

Is all the exterior insulation installed?

styxplo

It is a Aube TH114-AF-024T. It is using a slab sensor. The boiler does not have outdoor reset. My goal is to keep the barn around 50 or so. Right now the thermostat is set to 75 and it’s 56 in the barn. Im slowly lowering the thermostat to try to get to the 50 degree temperature. I’m trying to find a somewhat happy medium between comfort and energy usage. Just trying to take the chill out of the barn and keep things from freezing. Thanks Mark

styxplo

Its not Insulated yet. I’m building a house and I have my wife’s and mines belongings in the barn which makes it impossible to put the ceiling panels up. The reason I’m even attempting to heat it this season is because I need a place to stain all the house stuff , to cut the vinyl siding and all the other stuff that needs to be warm. The house is way behind schedule because of all the rain we had this year!!! I kind of have the cart in front of the horse..... I know it’s going to make a huge difference once it’s insulated. It does have house wrap on the walls and bubble insulation under the roof panels.

DZoro

No insulation, don't hope for anything efficient. Heat setting will directly affect your wallet setting. Until the building is insulated the boiler will probably struggle the entire time.
D

styxplo

I understand it’s a huge volume to heat..especially with no insulation. I just wanna make sure I squeeze everything out of it I can, as far as settings and pump speeds, that I can efficiently as I can. I think I’m on the right track??

DZoro

Your best efficiency is keeping your water temp low. Keep it at 120*, that should keep you above freezing. Will keep the boiler operating at the most efficient level possible.
D

styxplo

Ok. Thanks again

GroundUp

I've seen enough of these systems to know one when described. I said "boiler" because what you have is nothing more than a Takagi tankless water heater with a HydroSmart sticker on it and a price markup. The flowmeter that comes with them is always quite inaccurate, and the thermometer isn't always right either so I think we'd be a lot safer agreeing with the flowmeters on the manifolds seeing as they are showing 120k at 93%. You're going to use a lot of fuel heating an uninsulated building, there's no way around that. As others have stated, a lower water temp will gain you a little bit but you've got it close to as good as it's going to get right now. I've been known to custom build and ship quite a few of the Menards type heating panels that actually fit the space at a much more attractive price while using name brand parts, should you have interest in such a thing when the house is ready.

styxplo

ok....that makes sense now with the 2 different BTU's I came up with also. I knew something was giving bad feed back just wasn't sure what. Now that I've researched and learned a bit more ( I purchased the hydrosmart setup a year ago) I added up the materials they used to build the panel and realized that they are marked up an extreme amount. I am interested in a purchasing a panel in the near future for the house. How would I go about contacting you for some info?