Pond Boss
Posted By: R&R Hot Water Heating System - 11/18/13 05:46 PM
Looking for any and all the info and or DIY experience on in the floor heating systems. Building a pole barn as we speak. It will be about 2000 sq. ft. Future log cabin will be about 1400 sq. ft. with a half a loft and a full walk out basement. and an attached two car garage. the plan is to install the heat in all areas. Thanks in advance.
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 06:25 PM
I've done several radiant floor setups. How elaborate depends on budget. I'll do a quick outline:

1997 Shop 1 36x48 with 14' sidewalls. Slab on grade with 6" curb. I always prefer to keep the wood up high and dry. Radiant floor heat one single zone 7 loops approx. 250' each. Poly vapor barrier first then 1" blue styro sheets. Also styro up the outer face of the grade beam. 1/2" rebar 24" OC and floated up into the slab with stones. Tube tied to rebar with wire ties

2003 shop 2 40x40 with 13' sidewalls. Frost wall/footing for this one slab "floated" within. 1" styro nailed to outside of frost wall. Floor set down 12" below top of wall with grade being near top of wall at rear and "daylighted" doors out the front. Vapor barrier, 1.5" styro, 1/2" rebar 24" OC and floated up with stones. Tube tied to rebar with wire ties.


I ran a 6" Insul-Seal PVC pipe underground between the buildings. Through this I plumbed phone wire, stat wire, hot and cold running water, compressed air, and heating supply and return water. Boiler in shop #1 runs both buildings on a priority relay. Priority relay just means that the buildings take turns so that in super cold weather they don't fall behind.


2007-2009 House Nearly 6,000 sq ft 2 story full basement with walkout and semi divorced mechanical room. ICF exterior foundation walls. Being a basement the supporting material is the small stone to code aprox 8" thick I believe. Poly vapor barrier, 2" foam insulation, 1/2" rebar 24" OC floated up on stones. Additionally radiant floor heat on all levels in home. This was done with 1-1/2" lightweight gypcrete poured over tubes that were stapled down to sub floor. Heat is ground source Geo thermal water to water unit. We basically make either hot or cold water and store in buffer tank. Hot water circulates in the floors plus either hot or cold water can circulate through a fan coil unit for conventional forced air operation. Heat backed up with a Takagi Tankless water heater that provides all domestic hot water and the backup heat through a water to water exchanger. Supplemental heat (main) is a wood fireplace by RSF. This is an outstanding unit. The Canadians really know how to build a quality piece.

OK that is the background on my stuff.


I also did a small 24x24 garage for the Mother-in law similar tube and bar setup and used a Rheem tankless water heater. This was a "donation" and done relatively inexpensively.
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 06:55 PM
OK so general guidelines that I follow:

Insulation: Thicker is better. Less chance of breaking when the guys walk on it and keeps the heat in the slab where it belongs. If doing again I might consider having a 2" closed cell layer sprayed in place as the ideal setup.

Tubing: 1/2" tube (prefer Pex-al-pex for formability) and 12" OC. Be sure it is "barrier" tube. I like to run the perimeter runs 6" OC as well as near doors or other cold areas and you can let the distance widen a bit in the center. I prefer to keep the runs at 250' or so and make it up as I go along. Good pex has length markings on it so you can read and know what you have left on the roll. Keep the lengths as near to equal as possible for best flow balance. Once laid out I thread the ends of the tubing through 3/4" PVC EMT elbows and screw clamps to a plank that will be encased in crete. This way you have a PVC "sleeve" to protect the tubes from being "cleaned off" accidentally plus you match the manifold spacing.


Manifolds: You can use simple copper sweat manifolds or you can use fancy ones with balancing valves. The shops and basement have simple copper, the house has nice cabinets. I would suggest mini ball valves on each end of all loops in case you have to shut one down for any reason.

Controls: I will never do another in floor system without a temp slab sensor. Tekmar makes the best that I have found. While you want to maintain a nice air temp, the slab temp is more important. Without it you will get a lot of "flywheel" effect where the slab cools down then the system runs and runs and runs only to flywheel right past the set temp.

Boilers: I started with an older 85% Slant Fin brand wall mounted boiler. Still have it, but I took it out and replaced with a Triangle Tube Prestige Excellence that has built in domestic hot water so we can have a bit of hot water in the shop. The TT has been pretty good, but has had some hard lockout issues randomly. The newer units with the Trimax controls are supposed to address this.

You could do a water heater be it tankless etc, but the combustion efficiency is pretty low on these. They are designed to get the water hot fast and not run the duty cycles that a modern condensing boiler runs.

Geothermal: This is the ultimate in my opinion. Especially with a water source. You could run the "field" under water in a large pond and not have to deal with the big trench. Geo is expensive up front, but the payback time is pretty reasonable.




I'll see about some pics next
Posted By: Bill Duggan Re: Hot Water Heating System - 11/18/13 06:57 PM
Why do you need to heat hot water?
Posted By: esshup Re: Hot Water Heating System - 11/18/13 08:04 PM
Originally Posted By: Bill Duggan
Why do you need to heat hot water?


'cause he wants it hotter? laugh

Bill, I catch myself (most times) making the same mistake. wink
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 08:23 PM
This is in the house, but a good example of how I sleeve the tubes. In the shops I put the supply in back and the returns in front offset for access and just a couple inches apart.






Attached picture IMG_1148resize.jpg
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 08:37 PM
Here are the manifolds in the second shop. Also the conduit that I used to plumb between them.





Attached picture Heat Manifolds.jpg
Attached picture Heat Tube Conduit.jpg
Posted By: R&R Re: Hot Water Heating System - 11/18/13 08:49 PM
Hesperus, Great advice and pic's. I've already purchased 150 sheets of 1" thick high density blue board. 4'x20'. got it for a little less than $14 a sheet. Less than 1/2 of new cost. Was planning to double up for 2" of thickness over a vapor barrier. And maybe a 5" slab as suggested in my pole barn thread. I thought I would go geo thermal in the beginning but I'm just not sure right now. Kinda leaning towards just a high efficiency propane unit. I like the idea of domestic hot water also. Is there a general rule of thumb on how far you can go to a separate out building?
Posted By: R&R Re: Hot Water Heating System - 11/18/13 08:57 PM
Originally Posted By: esshup
Originally Posted By: Bill Duggan
Why do you need to heat hot water?


'cause he wants it hotter? laugh

Bill, I catch myself (most times) making the same mistake. wink


Ok. Cool water Heating system. LOL
Posted By: R&R Re: Hot Water Heating System - 11/18/13 08:58 PM
Hesperus, Are you saying a ball valve on each floor loop would be better?
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 09:15 PM
Originally Posted By: R&R
Hesperus, Great advice and pic's. I've already purchased 150 sheets of 1" thick high density blue board. 4'x20'. got it for a little less than $14 a sheet. Less than 1/2 of new cost. Was planning to double up for 2" of thickness over a vapor barrier. And maybe a 5" slab as suggested in my pole barn thread. I thought I would go geo thermal in the beginning but I'm just not sure right now. Kinda leaning towards just a high efficiency propane unit. I like the idea of domestic hot water also. Is there a general rule of thumb on how far you can go to a separate out building?


I think I would look to glue the sheets together for strength.

Set things up for flexibility. Stub water lines etc through tubes like I did.

Geo is ultimate, but quite spendy.

Ball valve on each end of each loop is best. Also aids in bleeding.


Are you going to do you own boiler install?
Posted By: R&R Re: Hot Water Heating System - 11/18/13 09:23 PM
Glue as is liquid nail kinda thing? I will do as much as possible. I'm an Electrician by trade and have a lot of friends in other trades.. Sometimes I do things I wish I hadn't though.
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 09:24 PM
If you are in heavy soils and prone to radon I have some ideas on a radon mitigation fan setup as well. We did it just for the sake of doing it here.
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 09:25 PM
Originally Posted By: R&R
Glue as is liquid nail kinda thing? I will do as much as possible. I'm an Electrician by trade and have a lot of friends in other trades.. Sometimes I do things I wish I hadn't though.


If you step on a single 1" it will break easily unless supported completely. Using some sort of PL to stick it together should aid the strength just make sure it's compatible.
Posted By: R&R Re: Hot Water Heating System - 11/18/13 09:28 PM
Understood. I figured I would stagger the joints also. They are cut with a ship lapped edge.
Posted By: Hesperus Re: Hot Water Heating System - 11/18/13 09:41 PM
Here is the modern version of the boiler that I have:

http://www.triangletube.com/TriangleTubeProduct.aspx?CatID=1&PID=19

It's done very well for me, but the controls on mine are older and simpler low voltage stuff. The new ones are microprocessor. I have yet to have to replace anything in mine, BUT it has locked out a couple times for odd reasons. The way that TT explained the last one was that the unit is sensitive to induced currents in some of the circuits. They are particular about how the igniter wires etc are routed and that they don't come in contact with metal etc. The new microprocessor should take care of that.
Posted By: fish n chips Re: Hot Water Heating System - 11/18/13 10:31 PM
Originally Posted By: R&R
I like the idea of domestic hot water also.


I have a set-up that has done really well for me. However, I use wood for my fuel and I don't know for sure if it would work on domestic hot water and geothermal. It's just a tube inside a tube for heat transfer, and the water naturally circulates around and back into water heater. If you are interested let me know and I will get some pics.
Posted By: esshup Re: Hot Water Heating System - 11/18/13 10:33 PM
Could you elaborate more on the Geo system? A friend is in the process of designing a pole barn that will have it in the whole floor, and possibly in the apartment area in the 2nd floor. I don't know if they are going with the drilled in to the earth (closed loop) or open loop from a well and have the overflow go to the pond. There is a 1 ac pond that is 300' away from the building site.
Posted By: R&R Re: Hot Water Heating System - 11/19/13 12:37 PM
fnc, originally that was my plan. But the older I get the less I like depending on wood. Thanks.
Posted By: fish n chips Re: Hot Water Heating System - 11/19/13 02:38 PM
I wasn't referring to you using firewood for heat. I agree, you sure don't want to mess with it in later years. I was saying that I transfer my wood heat to the domestic hot water heater. Perhaps you can do the same by means of geothermal, propane, or whatever you choose, with the same type of configuration I have at the hot water heater.
Posted By: R&R Re: Hot Water Heating System - 11/19/13 05:39 PM
Gotcha...... By all means. Any info,pic's, etc.... would be great. Thanks.
Posted By: Hesperus Re: Hot Water Heating System - 11/19/13 06:42 PM
Originally Posted By: R&R
Hesperus, I thought I would go geo thermal in the beginning but I'm just not sure right now. Kinda leaning towards just a high efficiency propane unit. I like the idea of domestic hot water also. Is there a general rule of thumb on how far you can go to a separate out building?


Geo is not for everyone no doubt about it. Our Geo has a "desuperheater" that circulates warm water through the water heater. The theory behind it is sound, but in practice it needs a bit of alteration in my opinion. Basically, I consider it ineffective if your water heater actually works. You are circulating warm to hot water through a tank that is already hot. What we did here was install a Marathon (all poly) water heater as a buffer tank and left the elements off. The desuperheater warms the water in this tank as needed. This warm water goes to the Takagi tankless that kicks it up to 119°f for delivery.

How much domestic hot water do you need? The TT with built in only has a 14 gallon tank so it's not a whole house deal. If you want to make full family DHW from the boiler you would the solo unit and an indirect fired water heater unit. The boiler will make the hot water and a relay control will direct where it goes. You'd essentially either circulate hot water through the unit, or the floor system. These are very efficient and very quick recovery as well. If you go indirect I have a 30 gallon Bock unit here brand new in the crate. A 30 gallon indirect will deliver on par with a 50 gallon conventional.

As far as distance, I'd say a few hundred feet. If you insulate proper it's not too bad to move hot water.
Posted By: R&R Re: Hot Water Heating System - 11/19/13 07:56 PM
Thanks Hesperus, I'll let you know when I'm finalized on a few other issues as to which direction I'm headed.

Basically I have a buddy who has his own HVAC company but doesn't deal with boilers so much. When I questioned him on Geo-thermal he said( After questioning me on a lot of things) That based on the size of my house and barn and my age etc..... That he didn't think it was worth the up front cost. So I'm still on the fence. Right now I just want to rough in my barn slab.
Posted By: Hesperus Re: Hot Water Heating System - 11/19/13 08:09 PM
For point of reference, our house which pushes 6,000 sq ft and has a lot of glass has a total annual HVAC cost of about 8,000kwh electricity plus 7-8 face cord in the fireplace. That's a bit under $900 in electricity (no breaks for the rates with our utility) plus $400 in wood if I were to buy it. We keep the temp around 72° in the main living area in winter.

The shops are kept at 62°f more or less and will use about 1200 gallons of LP gas I would guess in a season.

The pic of the house is from 2008 before we were moved in:



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Posted By: Hesperus Re: Hot Water Heating System - 11/19/13 08:24 PM
OK so lets get back to the radiant floor:

So what I have learned from operation is that I use a set temp (air) that is reasonable. In the case of the shops it is 62°f. What Tekmar brings to the table is slab sensing. This allows me to set a max slab temp of say 72°f and a minimum of 64°f. This keeps the floor from getting too cold between cycles or too warm if it gets really cold outside.

In the house I have the rooms all zoned individually. Thermostats are located remotely and have slab and in most cases remote air temp sensors mudded into the drywall. The kitchen is slab only and holds a minimum of 71°f. Master bath swings the floor minimum up to 74°f at 9pm for shower time. The dogs use the sun porch and their floor is set at 62° minimum.

If you set the minimum slab temp at a nice level and set room air temp below what the floor min normally maintains it at the stat will hold the minimum slab temp.

The pic below is my office. As point of reference, the dormers are over 7' wide inside. It shows that the tubing can run whichever direction. If you follow you will see that one loop runs up to the far dormer does a bit of the main floor then returns. The next loop does the middle floor and the third loop does the opposing dormer. It also shows a conduits stubbed out into the floor I placed the remote slab sensor in this conduit and caulked the end shut. It also shows the first layer of sprayed closed cell foam. The entire living space is sealed. There is no vented attic in the house.





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Posted By: R&R Re: Hot Water Heating System - 11/19/13 11:11 PM
VERY NICE!!!!!

I'm not sure . Are you on Geo-Thermal?
Posted By: R&R Re: Hot Water Heating System - 11/22/13 03:03 PM
Got a meeting set up with a guy at a local supply house we deal with. Any good question's , tips etc...... anyone can think of to bring to the table???? Thanks.
Posted By: Hesperus Re: Hot Water Heating System - 11/22/13 03:50 PM
Some details of the cabin plans would help.

Plan for a forced air system for circulation.

Constant fan circulation is best with a fresh air intake for the ducting (or better yet a power exchanger) and if you like things to be super quiet plan a section of flex in each run to cut out the blower noise. I also hate pinging ducts so address this when building.
Posted By: fish n chips Re: Hot Water Heating System - 11/27/13 12:40 AM
Originally Posted By: R&R
Gotcha...... By all means. Any info,pic's, etc.... would be great. Thanks.


Sorry it took so long to respond:

Heat source is an outdoor wood boiler. Water comes in and flows over the pipe of domestic hot water(DHW) by means of a jacket that surrounds the pipe. The water from the boiler never mixes with the DHW. The DHW tank is piped from the drain on the bottom back to the top, and the water being heated makes it circulate back into the tank and heats the whole tank, coldest water leaving tank at bottom to begin the process all over again.

Electric source is turned off while it's being used, turned back on during the summer. Mixing valve is needed so the water that is used at the faucet doesn't scald anyone. Needed because you don't have an electric switch that controls the heater(it is unplugged), and yes it gets that hot.

Hope this makes sense. Let me know if you have questions...

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