48x39x14 shop build

[ovrszd]

Yeah Greg, I started a thread. I'm on my phone and not smart enough to link you. Maybe search for threads started by me.

Yep, weather has crotch kicked us a couple times. Have the walls up. Hope to set trusses next week. Who the He** builds a house in the Winter anyway.......

 

[farm boy00]

Ive had a little exposure to in-floor radiant heat, as my friend the beeman has it in the floor of his new section of his building, about 50'x100' wood shop, and 20'x100' lobby/commons area/lunch room. Powered by wood fired boiler/heater. My dad helped design and install the original system about 15 years ago, I helped maintain it and modified a few things when I worked for him about 5 years ago, but its been a reliable system that he's quite happy with. But this is a commercial situation, business use, heating about 10k feet, all with wood fired boiler, supplemented by a wood stove in the older section.

Ive been trying to absorb what you all have shared, and hope I can use the info someday.

Richard, how's the house project coming? Do you have a thread on it alone? I havent noticed one, but read your posts in other threads that mention it... I'm sure winter weather is slowing down progress.

Here is the house build thread.

New House Build

 

[ovrszd]

Here is the house build thread.

New House Build

Thank you very much for helping with that.

 

[bigtiller]

Yeah Greg, I started a thread. I'm on my phone and not smart enough to link you. Maybe search for threads started by me.

Yep, weather has crotch kicked us a couple times. Have the walls up. Hope to set trusses next week. Who the He** builds a house in the Winter anyway.......

My foundation and basement walls were poured December 23, 1997. The good thing about building in the winter is not having bugs invade the house before it gets enclosed.

 

[ovrszd]

My foundation and basement walls were poured December 23, 1997. The good thing about building in the winter is not having bugs invade the house before it gets enclosed.

Yep. No bug worries here.

 

[dstig1]

I wonder if systems using boilers operating in the 160-170 range using hard water would have even more problems?

Ah boilers. This is the source of religious wars in radiant heating circles: boilers vs tankless. Anyone who is a pro in the HVAC field and installs or designs radiant heat systems will tell you that only an idiot would use a tankless heater for this as they are not designed for it as they are supposed to take cold water and heat it hot, not warm return water and heat it a bit more. And it will void your warranty. Plus - all those tiny internal passages that they have to get the water to heat up so fast will create too much flow restriction. And all the people that are using tankless will tell them "but mine works just fine" ...And then the screaming starts...

Thing is, my unit has 2 parts to one of the sections in the manual. One is labeled DHW use and the other is labeled Heating Applications. So the manufacturer seems to think they will work. They have different warranty terms for the 2 applications, as the heating usage will make it run far more than a DHW unit would. but it is still warrantied for heating applications.

Then the "tiny passages". Well if you recall my super long post above, I had my DHW heater fail as the heat exchanger had hard water scale build up in it. After I had confirmed with the manufacturer that they did not want it back, I asked about cutting it open and he said go crazy. The first thing you see is that the HX is basically a 1/2" copper tube that is snaked back and forth through tightly packed copper fins. I cut lengthwise through a couple of the tubes to see what it looked like inside. Lo and behold it is a clear copper pipe with one twist - they wind a very thin wire inside it like a wide open spring which you can see the marks inside the tubes in the photo below. You can also see the whitish hard water scale on the right side inside those 2 tubes that are sliced through lengthwise. That was enough to kill this HX. But what you do not see is any "tiny passages". Now my theory on the spiral wire is that it is a fluid dynamics engineering trick to eliminate the laminar flow boundary layer and make it turbulent for better heat transfer, and that probably raises the back pressure of the system over a pure clear pipe, but again - no tiny passages.

The holy war rages on, unabated... I have had to learn waaaay too much about radiant heat and tankless heaters the past few years. :banghead:

 

[RayfromTX]

Off topic add to a previous comment above. Radiant heat will provide a less dusty environment than forced air if the air handler or ductwork is located in a vented attic or crawlspace. This is because most of the leakage tends to be on the more complicated and lengthy supply side and therefore when leakage occurs it takes air from in the living space and allows it to escape to the outdoors. The air that replaces that lost indoor air will carry dust, pollen, humidity and temperature loss with it. This affect on indoor air quality is the best argument about unvented attics or in this case radiant heat.

 

[ovrszd]

Dave,

Another excellent post!!!

Are you convinced then that hard water is why you had problems? Certainly appears that way.

Would a corrosion inhibitor injected into the system be worthwhile?

I am using a Rinnai tankless heater. My installer said to be sure and register the warranty as DHW useage.

In my current home I use a tank type electric water heater. Twice I've had electrode failures over the past 20 years. I contribute both to water quality. The build up on the electrode prevents it from transferring heat into the water efficiently. Thus the electrode overheats and fails.

This discussion makes me wish I had installed a softener in my shop....

Thanks again Dave for excellent input. Please add any other comments you want.

 

[truckdiagnostics]

These are all tankless

Shop radiant - 120F
House radiant 130F
House DHW - 140F

I started the house radiant at 120F but was having low flow issues (maybe also related to the hard water) so i ended up bumping it up 10 deg as pretty much the only lever i had left to pull on. It worked.

The above temps are high, when a radiate floor system is designed and working correctly you do not need temps this high! My son and myself looked at your pex layout for your shop and house. If for both that is the final lay out before pouring you do not have enough tubing in your floor. this is why you are having to run a higher water temp. The pex should be 8 to 12 on the outside walls 12-18 on the rest and loop back and forth.

Also, boilers do not like gycol(anti freeze) I would not run gycol in/through any boiler. Yes over time in your type of boiler hard water would be an issue. As for hard water, I do not have a boiler but the water in our system is as hard as it gets, been there for 18 years, we are just now having issues in the house garage's flow control.

As an example we have 28 x 32 attached garage, over head door opens maybe 4 times a day. At 32 outside temp I can heat that garage with a 40 gal electric water heater, to 60 degrees. Over thanksgiving, we can get it to 68 without opening the door. I know we just did it. When the 40 gal unit can't keep up I supplement with a geo unit. The water temp going to the floor is 85. The recovery is poor but for that application we do not need it.

Our shop which is 30 x 60 one zone, water temp going into that floor is 100. We heat this with a geo unit, then have water to air exhanger for office. Then chill the water in that for cooling in the summer.

So your question is great how do i fix it. One if there is gycol in the system remove it. if you do not want to do that put water to water exchanger in. thinking out load I wonder if I buffer tank would help your situation? Basically use a hot water heater, and make the tankless tanked., that and a water to water exchanger you could leave the gycol in. You are stuck with having to run those high temps.

 

[truckdiagnostics]

Ovrszd,
The manifold in your shop..... not good. You need a manifold that has flow indicator on the inlet and control valves on the outlet. When your system first started up with that manifold there is no way they could have gotten the air out. It will come out over time, due to the air separator, but how long! We maintain you still have air in your tubing in the floor. With that type of manifold the tubing would have to be exactly the same length and same number of bends to get even flow and that is not possible. Make them replace it and bleed it right, now. If you do not when you go to replace anything getting the air out....

For your house ask to see the tubing layout. Then check to make sure it is laid out that way. You do not need a lot of zones if the tubing is laid out correctly, and it is radiant. Also, I would ask to see the plumbing layout, if they do not have either, consider finding another contractor. When a radiate floor system is designed typically the supplier of the components will do it. Your shop looks like someone that typically does plumbing did it. We believe those are potable water manifolds, not radiate heat manifolds.