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Topic Review (Newest First)
02-27-2011 05:42 PM
35terraplane
radiant floor heat

Quote:
Originally Posted by trees
Bob, I use the term "loop" because the line /water leaves the manifold and makes its way through the coils and back to the manifold. A "zone" one or more "loops" off a common manifold and controlled by a thermostat. In my shop, there are two zones: one has 4 loops and one has 3 loops. The 4 looper covers 1400 sq ft and the 3 looper covers 1000 sq ft.

Before signing the contract for the system, I spent several evenings on the net where there is a ton of info on various systems. One thing that was common was copper is definitely the best tube for circulating the water: flexible, sturdy, and the best heat transfer rating PEC is the 2nd choice and the only reason I used it was the terrible price of copper tubing. Using copper would have almost doubled the cost of the system.

The pressure testing of the loops was a local code item, but I would have insisted on it anyway because finding a leak would be a bear and then the repair is not something I would want to do or have done.

Trees
Trees I used loop because I didn't have a clue on what else you call it.
After writing my post, I called the guy that built my house and shop, I got to thinking about a pin hole or something. He told me they did a pressure test, I guess I was sleeping in that day.

Bob


She was only a whiskey maker,

But he loved her still.
02-27-2011 04:30 PM
trees Bob, I use the term "loop" because the line /water leaves the manifold and makes its way through the coils and back to the manifold. A "zone" one or more "loops" off a common manifold and controlled by a thermostat. In my shop, there are two zones: one has 4 loops and one has 3 loops. The 4 looper covers 1400 sq ft and the 3 looper covers 1000 sq ft.

Before signing the contract for the system, I spent several evenings on the net where there is a ton of info on various systems. One thing that was common was copper is definitely the best tube for circulating the water: flexible, sturdy, and the best heat transfer rating PEC is the 2nd choice and the only reason I used it was the terrible price of copper tubing. Using copper would have almost doubled the cost of the system.

The pressure testing of the loops was a local code item, but I would have insisted on it anyway because finding a leak would be a bear and then the repair is not something I would want to do or have done.

Trees
02-26-2011 02:33 PM
66GMC When I built my garage, I was pretty hyped about in-floor heating.
Yes a warm floor would be a godsend if you spend a lot of time lying or kneeling on it.
The downside is that recovery times from opening a door would be considerable, and might even require a forced-air unit to re-heat the air.

After studying all of that, and weighing the costs and risks involved ... I was persuaded by a few friends to simply install a radiant-tube heater, along with a couple of industrial-type ceiling fans.


The radiant heat warms ME more than the air, but it also warms things like windshields and car bodies ... which in turn help to warm the air. My garage is well-built with 6" walls, vapor barrier, and R20 insulation.

The ceiling fans help to circulate the air under the vehicles and to warm the floor to a relitively comfortable temp. They also keep the windows clear.

In summer, the air movement over the cool engineered concrete slab helps to keep the garage at a fairly consistent and comfortable 20C (70F) temperature even during the hottest of days we get here.

It was relatively cheap to purchase and easy to install, and very economical to run as well. I heat my garage continuously as I have pets that live out there, but friends run theirs only when they plan to use their garage. It only takes about 1/2 hour before it gets comfortable enough to be out there.
02-26-2011 02:32 PM
LATECH
Quote:
Originally Posted by Old Fool
That is just plain bs , Expansion and contraction? how much do they think that concrete slab grows and shrinks? PEX tubing has a 100% minimum expansion rate. How do you think it survives having the end expanded to insert a fitting , such as the Wirsbo PEX system uses? PEX tubing is not affected by concrete, it is designed to be used in concrete. Your source must be referring to someone who used some other type of tubing. Can't fix a leak? Yes it is a bit difficult to fix the leak, you need to chip the concrete away from the tubing to put a repair coupling in it, but unless you drill a hole in it there won't be a leak. A continious loop of PEX poured into concrete is virtually impervious to damage
ALLRIGHTY THEN. Now that we have cleared that up.Sure am glad i didnt use that guy for my house.
I was questioning the info I got .I personally dont like pex anyway, too newfangled.
I do understand what you are saying about the expansion and contraction of the tubing and the concrete.
Like I said , what I have heard were horror stories, as far as I am concerned the jury is still out. Call me stupid if you like, I just dont jump on every NEW thing as the BEST thing.
I see alot of posts that guys put up saying it is the way to go,must be something I am missing. I am kinda hardheaded
02-26-2011 12:33 PM
35terraplane
radiant floor heat

Quote:
Originally Posted by trees
A qualified in floor heat guy will pressurize the loops for about 48 hours before the pour and leave it on until ready to hook up the system to the manifolds. Having pictures of the loops before the pour helps to ease you mind when core drilling for anchor bolts later.

Trees
They never put any pressure on mine, but it was two big loops, one for each zone.
My house is the same I have five zones and they are each one loop no splices or breaks in tube from start to finish, And they run pretty close, when I say loop I might be using the wrong term, as the tube went back and forth across the room or zone, not a big circle.
It's just like wiring a car less breaks in a wire less trouble.
So one end was hooked up to the out manifold, the other to the return, there were no breaks in between.

Bob
02-26-2011 12:06 PM
trees A qualified in floor heat guy will pressurize the loops for about 48 hours before the pour and leave it on until ready to hook up the system to the manifolds. Having pictures of the loops before the pour helps to ease you mind when core drilling for anchor bolts later.

Trees
02-26-2011 07:44 AM
timothale
pex radiant.

All splices- joints must be out of the concrete. continuous run under the concrete. as far as expansion contraction, I have seen concrete roads buckle in the hot sun . That should not be a problem inside a building out of direct sun. if you build over expansive clay soils you can have floor cracking. In a lot of areas the local building department already has area soil maps. I hit clay down at 4 ft. My engineer spec'd 3 ft sq footings with 12 in sq posts with 6 pieces of 1/2 rebar uprights with 3/8 hula hoops 6 in apart for the steel column supports. There has been no movement in the 20 post locations. The footings must be deep enough for the soil type or a grade post-beam system. 18 inch holes about 6 ft deep with rebar L'ed into the floor, and foundation walls about a foot thick floor around the edges and use lots of rebar in the floor slab. Plenty of crushed rock then poly vapor barrier, sand and foam insulation. Grade the area around the building to keep rain and snow melt water away. In my main 12 X 12 doorway I also brought out 1/2 rebar 18 inches apart to tie into the driveway slab The backhoe weighs about 10 tons. . In 9 years there has been no movement or cracking in the main doorway. . In the back door the slab has lifted about 1/2 inch, I didn't put in the rebar ties out like the front and the ground base level is 18 inches higher, not as good of drainage. I had about 100 yards of base gravel hauled for under the floor, I should have raised it more, but didn't like having to do a 3 ft in 40 ft ramp in front.
02-26-2011 06:52 AM
1ownerT Pressurize the PEX while pouring, any leak will be evident and easy to find as it will bubble up through the wet concrete, giving a chance to repair before the concrete sets.
02-26-2011 05:16 AM
Old Fool
Quote:
Originally Posted by latech
I have heard some horror stories from some of the HVAC guys here in Northeast Pa about the concrete not being so friendly to the pex tubing.
It doent like the expansion / contraction thing as well as the chemicals from the concrete while curing.If it springs a leak for whatever reason ,you cant fix it.
Honestly If it were me, I would put in radiant baseboard around the perimiter of the shop, use an outdoor boiler and an oil fired one for backup with a heat exchanger. There are outdoor woodstoves that can be multifueled, but I have checked into that for my remod, and they arent as efficient as putting in a dedicated unit.
With radiant it feels warm all the time and it is very even heat. Fanforced only feels warm when it is running, it stirs up a buttload of dust and its impossible to put the "unit" outdoors to contain the burner away from the air in the shop(VOC , solvents thinners etc. explosion...you get it)
I like the outdoor woodburner my neighbor has, itkeeps his house at 80 degrees inside all winter long.
I have an oil fired burner and my house is small and tight, I have used 275 gallons of oil so far this winter.
If oil keeps going up, I will be getting an outdoor stove and putting in a heat exchange for the hydronic (radiant baseboard) system in my house. If the fire goes down at night the oil fired boiler will pickup the slack.
Linn A
Quote:
Originally Posted by latech
I have heard some horror stories from some of the HVAC guys here in Northeast Pa about the concrete not being so friendly to the pex tubing.
It doent like the expansion / contraction thing as well as the chemicals from the concrete while curing.If it springs a leak for whatever reason ,you cant fix it.
That is just plain bs , Expansion and contraction? how much do they think that concrete slab grows and shrinks? PEX tubing has a 100% minimum expansion rate. How do you think it survives having the end expanded to insert a fitting , such as the Wirsbo PEX system uses? PEX tubing is not affected by concrete, it is designed to be used in concrete. Your source must be referring to someone who used some other type of tubing. Can't fix a leak? Yes it is a bit difficult to fix the leak, you need to chip the concrete away from the tubing to put a repair coupling in it, but unless you drill a hole in it there won't be a leak. A continious loop of PEX poured into concrete is virtually impervious to damage
02-25-2011 05:00 PM
35terraplane
radiant floor heat.

Quote:
Originally Posted by ogre
i do like teraplane's system. if you need air use the window units and then go with radiant floors.
my shop was retrofitted from an old barn

teraplane: nice freaking shop
Thank you, Since it was built I have had to add to it. In the picture behind my boat, and bathroom, I have added a 12' X 16' kick out for some more room, no heat in floor there but don't need it as it is not a work space.
Also wanted to make sure my shop had more sq. feet than the house, just to needle the wife a little.

Bob
02-25-2011 10:48 AM
ogre i do like teraplane's system. if you need air use the window units and then go with radiant floors.
my shop was retrofitted from an old barn

teraplane: nice freaking shop
02-25-2011 09:16 AM
trees 37, adding another on the opposite wall would make you doubly good.

Trees
02-25-2011 08:38 AM
37ford4dr to bring the heat down from my 14' cieling area where the electric heater hot air finally winds up i use a slow turning cieling fan that is switched with my lights and an 8" round duct that goes from cieling height to floor with a fan motor in it that is on a timer and every 15min of every hour it circulates the hot air back down to the ground level. this creates a 1* difference in temperature from the cieling area to the ground area. i even use the fan in the round duct when i dont have the heat on and it moves the warm air from the solar radiation back down.. my son actually declared that 8" round duct with the fan in it as one of my best ideas.
02-24-2011 08:13 PM
trees Copper coils are the best but were out of my budget. Did quite a bit of research on the web and decided that PEC is second best choice. The "experts" claim it has better flexibility for the expansion/contraction of the concrete than the copper, but the copper does have the best heat conductivity. You are going to have zones, whether you want them or not because you want to return the water to the boiler/heat exchanger with some heat still in it. The TEMP Delta does not need to be too wide, or it takes too many BTUs to get it reheated for circulation. In the larger section of my shop, I have three closed loops feeding from one manifold and the smaller section has the same. One thermostat in each section controls the pumps and these thermostats are located about the center of an interior wall. The pumps are 24 volt DC TACOs that have been used in industries for a long time and have a good track record.

Convection heat rises and it is very warm next to the ceiling when it is used. This is really wasted heat unless you want to install a system to return it into the ducts. Radiant heat does have some raising but tends to warm objects. The warm floor means warm feet and very comfortable on a creeper so the thermostat can stay low and still be comfortable. My office/bathroom is located 11 ft up and is not heated. It is about 7-8* cooler than the floor level. We have a small electric heater if we are going to be in the office any length of time and because the office is also insulated inside the insulated shop, it warms up quite rapidly. Of course, you don't linger on the throne if you had not planned your daily constitutional. This spring, we will install a Mitsubishi ductless heat pump in it that will cover our needs

Trees
02-24-2011 05:32 PM
LATECH Also , instead of using zone valves , I used the TACO 007 series pumps with the integral check valve. They work great for zoning, and it is cheaper as you dont need the valve and a pump. just a pump.Pretty easy to wire up too.
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