Under floor randiant heat questions
Is 12 inch spacing runs with metal plates spaced 24 inch apart enough to heat a home efficently for this type of installation?
Heres a photo of what I am trying to explain
Sorry about the size, I do not have anyway of reducing it.
Thanks for your time
Garry
Replies
I would say no way. I have 9" centers and plates spaced abou 3" from each other and it works very well, but its on top of the subfloor, not underneath.
You really need to have a heat loss calc done and design the system from there.
NRT Rob is the resident expert.
May work as auxilairy floor warming but you'll need a whole lot of insulation and very good windows and draft sealing to heat a house on that little heat. Maybe if you run the loops at 140 degrees but that might make it challenging on your water heater if the outflow from the floor was up at 120.
Only if you use it as supplemental heat and you have a big wood stove or forced air system to do the heavy lifting. In my humble opinion.
m
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"You cannot work hard enough to make up for a sloppy estimate."
It looks like the project is pretty far along, I would try to provide close to 100% plate coverage by reapplying the plates and adding additional plates. It looks like the tubing is less than 12" OC but if it is you need more plate coverage
The project has been completed according to the contractor. The system is very noisy (I am told by another source it is because of the Metal Plates) and the sunroom will not reach room tempature. It will get to 65 degrees and never quit calling for heat at 30 degree tempatures.
The floor in the master bedroom bath which has tile is always cold, This is just the opposite of the reason we went with this tyoe of heat.
The contractor says that he installed the system according to his warehouse's heat loss specs.
http://www.superwoodworks.com
Edited 12/19/2007 7:58 am ET by Garry
I would say that the contractors supplier is using the incorrect data. I have installed systems from southern Mi to Florida and they all heat the homes very well. There are a notebook full of calc that need to be done. Sub-floor thickness, floor thickness and material, window openings, insulation (walls, ceilings and floors). The problem is that the system is not being maximised, you do not have enough fin coverage on the pipe. Then you need to look at the length of the runs of the 1/2" pex, they should not exceed 300' from the manifold. Then there is the flow/temp calculation. You must have a temp gauge on the system, and hopefully one on the supply and a seperate one on the return. If you do not have these temp guages you need to get them installed. Real simple, the supply should be up to the calc temp that your contractor has and the return should read accordingly. Good Luck, if you house is not warm in the UP now.. .Brrrrrrrr
Just a couple of more items. What type of boiler are you using, how many zones, what model of pump? These are things that you need to know.
garry.... i saw the pic.... what i didn't see is how the system is insulated
it doesn't look THAT marginal... but without a good idea of how it got insulated ( it did get insualted , right ? ) it's hard to tell
looks like plenty of tubing....
if the next layer down were say ... foil faced polyiso.... then it should be working
what's the finished install look like before the ceiling got installed ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Also he said that it was noisy.I wonder if he had too long of paths, rather than have it broken up into several parallel loops..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
It is R19 insulation under the tubing. The building contractor and the heating contractor must have decided what the basement cieling should have for the R factor. There is no cieling in the basement at this time. Only the FG R19.
http://www.superwoodworks.com
Here's another shot at the boiler area. We have 3 zones on the main floor, 1 zone for the basement and 1 zone for the 2nd floor, so 5 all together.
The boiler Brand is Prestige made by TriangleTube.http://www.superwoodworks.com
Ok, I see the pressure guage, but where is the temp guage? Without the temp guage the system cannot be checked (and I have found that it is best to have one in the supply and the return). I noticed on another post that you said that you have R-19 under the tubing in the basement ceiling. Why? Are they trying to isolate the basement? After the tubing is installed there should be a reflective/insul barrier. I use Astrofoil. Staples up and gives you min R-7 plus it keeps the heat going up. FG (IMHO) is not the proper insulation under RH. By the way I tried to get an email link from your web site and it did not work. Is the ph # listed for the shop smith a good evening #? I would give you a call tonight after 9 if it is. Pass through your town on the way to Seney to Hunt each year.
There are digital tempature readings on the boiler as is is heating up but not any manual guages except for pressure. Originally the contractor said that he was going to put in a bubble foil type material but then he said with the plates and the insulation I did not need it.
I sent you an email with my phone number and email address.
Garryhttp://www.superwoodworks.com
He was right the first time.. Bubble foil is better IMO. I would use it with the R-19.
An air sealing ceiling in the basement might help.You do need some return side temp guages. RudyardGarett
Edited 12/19/2007 12:59 pm ET by Grott
Very unlikely to be enough tubing or enough plates. If your contractor "installed in accordance with his supply house specs", then his supply house should help him out with fixing the system. Whether they do or not, it is his job to make this system work, end of story. You didn't pay him to hang pex, you paid him to put in a radiant heating system, which is not heating.You should have, typically, no more than 4-6" between plates linear on the tubing. Two runs per bay. R19 fiberglass is adequate insulation if the basement is heated or well sealed, though I would increase it to R30 if it's a cold leaky basement.Those are lightweight plates. To avoid noise with them, he should have expansion loops in the tubing at the joist penetration ends, and you should be using variable and proper water temps in the tubing, and over a cold basement that plus the insulation quality are important details. However, they even may not be appropriate for your heat load, perhaps. Proper calcs could determine it. Using heavy gauge extruded plates would increase output, would probably eliminate noise with little other change to the system... and would increase cost quite a bit too.Finally, I am not sure that the boiler piping is up to snuff. That's a great boiler and it's a really nice looking pipe job, but generally I expect to see mod/con boilers piped primary/secondary, and I'm not seeing that here. (can you trace a piping path, through a pump, that does not go anywhere from the boiler except back to the boiler?) However I am not all that familiar with this particular boiler, and that might be accepted practice for it in particular for some reason (internal bypass, not as sensitive to flow as others, etc).-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
I do want to add, if the boiler is properly sized and its reset curve is properly set, it shouldn't ever stop running when it's cold. That's a modulating boiler, and as such, it should run consistently, modulating its output to the load.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Thanks,
I printed out your post and will show the contractor when he comes back.
Garryhttp://www.superwoodworks.com
I dont think anyone mentioned the size of the pex.I hope that it is atleast 1/2 and not 5/16. I have the same situation as you. 1/2 pex, one loop per bay, 16' on center joists, and alot more plates. My insulation is 1" foil board held down 2". I then back filled with FG. None of my loops are longer than 300'. I have heard talk of this way of doing it not to be the best but I have had no problems.
Yes the tubing is 1/2 inch and I agree, not enough plates and most say not enough tubing for my area.http://www.superwoodworks.com
they don't make plates for 5/16" pex.if they did though, smaller pipe works just fine. 3/8" underfit is much easier to run than 1/2" and results in almost no output drop, but you do need to run shorter loops.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Noise is from expansion and contraction in most systems. I have quite a bit of "ticking" when my system starts up for the first time in the morning if the water temp is high.Once the whole system is warm it is nice and quiet. It is most noticeable when I have had a wood fire going and the system cools down to 65 or so then kicks on in the early morning with water temps in the 120 range the sudden temp change makes the tubing expand quickly. I'm working on the reset curve to ease the change. Some noise is going to be there in staple up systems but it should be minimal, like the pinging of base board heat. Garett
This is a poping noise. Our last house had hot water paremeter heat so I know the type of sound you are thinking of. This noise will wake us up at night it is so loud. When the tubing is heating up or cooling off it sound like the floor is about to be pushed apart. I am told that the anealed aluminum plates do not have this problem.http://www.superwoodworks.com
Gary,
What centers is the framing on? 16" 19.2" 24" I think you are a little light on plates and may be in need of more runs based on heat loss for certain areas.
I'm from the EUP so I know it's been cold up there. Do you have insulation under the pex and plates yet to force the heat up into the floor?
What type of boiler and controls are you running? How well insulated and sealed is the house?
Sorry for the boat load of questions, NRTRob is the resident expert, you my want to ping him via email or instant messenger if he has them on his profile.
Garett
The joist are on 16 inch centers and the insulation under the tubing is R19 FG.
The house is very well insulated but has a buch of windows which was supposed to be accounted for.
Heres a couple of photos of the outside of the house to give you an idea as far as windows and doors. The photos are older shots before much landscaping but you will get the idea.
I have posted a couple of photos up higher in this post if you want to check out the boiler and pumps.
Were in the EUP are you from?
http://www.superwoodworks.com
You've gotten some good replies from others here. I'm no expert on this, but I'd be surprised if that's enough aluminum. Not saying it aint -- just that it would surprise me. (But I've been surprised before on this stuff.)
Some thoughts based on my limited experience:
Do your runs exceed max. recommended length? What are your input/output temps? If you don't have guages, you could try using an infrared sensor on the in/out pipes at the boiler. Or even a thermometer against the pipe covered with insulation. Check with the mfgr. on what the delta should be. If the temp doesn't drop enough, not enough heat is being delivered -- it's just circulating in the system likely because there isn't enough radiating surface. If it drops too much, half the run is cold water and you're not delivering enough heat to the floors to allow them to heat the space -- runs too long.
The popping is a bit puzzling. Is it coming from the plates as they expand? If so, and if you can still get to them, you might try loosening the fasteners a bit to allow them to move without so much noise. These systems can also make noise if you get cavitation at the pumps or overheating at the boiler. Look at the pressure guage to detect this. It should be steady. If it's jumping around, you got problems with the flow.
If any of this info is bogus, one of the heating pros will likely holler.
Mike Hennessy
Pittsburgh, PA
Mike, I gave him Marks number at Energy Reduction. The popping is probably due to the fact that there are not and expansion loops at the ends of the bays, out of the plate and a tight turn to go thru the joist.
I suspect the lack of a radiant barrier is causing a large heat loss. The radiant energy passes straight through FG and travels towards the coldest thing available.
It might also be prudent to put some foil lined shades in that sunroom for those cold days.
This is absolutely bull. What is this, a new marketing angle for these radiant barrier guys?Radiant energy does not go 'RIGHT THROUGH' anything. it goes until it hits an object, like wood, or fiberglass, and stops... after that, it must conduct through the object to re-radiate out of the other side. Perhaps some can go straight through glass or something, but not solid opaque objects.fiberglass has its problems, sure, but radiant energy does NOT go right through it any better than it goes "right through" wood. Please keep the radiant barrier MFG's marketing lies out of here.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Sorry for the unfortunate choice of words. Would your first choice for floor insulation over an unconditioned space be FG?
My first choice? Spray foam. Rigid, if you're using a method that actually requires an airspace between subfloor and insulation, sealed with spray.Failing that, I would choose R30 fiberglass (or maybe R19 in mild climates) over a radiant barrier any day of the week. Preferably encapsulated batts if you're over truly unconditioned space.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com