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[willieG]

for starters i would set your delivery water to the floor at about 120 and open your flow to  1 gpm to each loop..i think (only think) your taco 7 (if it is just supplying the loops and you have another pump at the OWB) it should be able to supply between 1/2 and 3/4 gpm to 5 loops of 1/2 pipe 250 feet long

personally i think 1/4 gpm is not near enough
in my opinion i would like to see the flow about 1 gpm or a little higher but that would require a bigger pump than you have i think

if your loops are kept under the 300 foot maximum and your gpm is within the recomended flow charts, your return temps should be able to be kept 10 to 20 degrees below delivery temps. remember a .1 gpm increase = 5 btu per square foot

Willie, been trying to understand the last part in red.  If 1 gpm is good for 10,000 btu/hr , then .1 would be good for 1,000? (with 20 deg. D t)  How do you figure 5 btu/sq.ft. increase?  Each 1000 btu/hr for 1500 sq. ft. as in this case would be .666 btu/sq.ft.?   I'm probably missing something, wouldn't be the first time.  Also, that would be btu available, not necessarily what the floor would emit.

1/4 gpm in 5 loops would be 1-1/4 gpm so a possible 12,500 btu/hr.  from the 1500 sq.ft. slab. (20 deg.Dt) Under slab insulation would be a big plus.

the initial output would not be figured at 10,000 btu/hr as the inlet temp to the floor heat loops would only start at 120 degres and not 180...therefor output is quite a  bit less

at 1/4 gpm in the 1/2 inch pex you would be moving only about 40 fpm it would take almost 6 min for the water to travel the length of a 250 foot loop.. that is why return temps are so low and btu output is low you have to move the water a little faster to get to your desired 20 degree delta

i am running my loop in my basement at the max for 1/2 pex and i think i am very clsoe to 2 gpm with an entering temp of 120...my loop is 250 feet long and my return temp is 110. my loop is 2 inches below the top of the slab and i have 2 inches of foam under the slab.

[slimjim]

Thank you Willie, I sure wish I could do math the way you guys can, How about teaching me how to post pictures?

[willieG]

Slim i havent posted a photo in  a long time on this board. i used to just open my photo in a program such as as "paint" and shrink it to about 30 percent of original size and the site would allow me to post. (most sites like this have a maximum file size to try and keep room available)

or you can post yoru photos to a storage site such as "photobucket" and then paste and copy a link in your message to take the viewer directly to your photo (s)

http://i67.photobucket.com/albums/h308/billie_boy7/silvers%20replacement/012-1.jpg

[slimjim]

I'm going to have to see it done, I'm just hillbilly enough to not understand what you are talking about, Scott can explain as he already tried with me, Sorry.

[willieG]

ok lets see what happens..if my post goes i will send you a pm on how it is done step by step

[slimjim]

That worked Willie, next step is to teach me how to do it!

[idahohay]

Clueless, I hope you are getting some heat out of your slab by now.  I was thinking you have additional radiant heat capabilities in your house but are just concentrating on the basement first?  You have an 007 for your basement slab, a ?? at your boiler? and what other pumps if any and what size?  Is there insulation under your floor slab, or basement walls?  Also, can the installer you mentioned tell you anything more about your installation?  This information can help the pro's advise you, I'm no pro, just trying to learn here.

Willie, I'm math challenged so having been forcing myself to figure some of this stuff out.

The only clues from Clueless were 5 loops at .25 gpm, a supply temp of 110, return temp 60.  Thats a Dt of 60. So  1.25 gpm x 500 x 60Dt= 31,250 btu/hr.  (assuming 5 loops at 1/4 gpm) You said output would not be 10,000btu because water was not 180.  Nobody would send 180 into a slab, but if so, btu output would still be gpm x 500 x Dt=btu/hr.  As the slab temp. approaches the air temp, the Dt would narrow, then at some point, you would only need to supply enough btu to cover the heat loss and maintain the desired room temperature.

Also,I still don't understand the statement "a .1 gpm increase=5 btu per sq. ft."  Is that some sort of rule of thumb? To me it seems like something that could occur  but other factors like how many square feet, spacing of pex in slab, slab insulation, would all influence btu/sq ft. In your own basement, (2 gpm, Dt 10 deg) you would be supplying btu's at the rate of 10,000 btu/hr.  If you increased you gpm to 2.1( and your Dt remained the same) your out put went up to 10,500. If there was a 5 btu/sq.ft increase, your basement is 100 sq.ft.Any thoughts? I know I'm missing something here. Please help, my wife just gives me a blank stare when I bounce this stuff off her.

[Crow]

Clueless, I hope you are getting some heat out of your slab by now.  I was thinking you have additional radiant heat capabilities in your house but are just concentrating on the basement first?  You have an 007 for your basement slab, a ?? at your boiler? and what other pumps if any and what size?  Is there insulation under your floor slab, or basement walls?  Also, can the installer you mentioned tell you anything more about your installation?  This information can help the pro's advise you, I'm no pro, just trying to learn here.

Willie, I'm math challenged so having been forcing myself to figure some of this stuff out.

The only clues from Clueless were 5 loops at .25 gpm, a supply temp of 110, return temp 60.  Thats a Dt of 60. So  1.25 gpm x 500 x 60Dt= 31,250 btu/hr.  (assuming 5 loops at 1/4 gpm) You said output would not be 10,000btu because water was not 180.  Nobody would send 180 into a slab, but if so, btu output would still be gpm x 500 x Dt=btu/hr.  As the slab temp. approaches the air temp, the Dt would narrow, then at some point, you would only need to supply enough btu to cover the heat loss and maintain the desired room temperature.

Also,I still don't understand the statement "a .1 gpm increase=5 btu per sq. ft."  Is that some sort of rule of thumb? To me it seems like something that could occur  but other factors like how many square feet, spacing of pex in slab, slab insulation, would all influence btu/sq ft. In your own basement, (2 gpm, Dt 10 deg) you would be supplying btu's at the rate of 10,000 btu/hr.  If you increased you gpm to 2.1( and your Dt remained the same) your out put went up to 10,500. If there was a 5 btu/sq.ft increase, your basement is 100 sq.ft.Any thoughts? I know I'm missing something here. Please help, my wife just gives me a blank stare when I bounce this stuff off her.

Haha, my wife does the same but this math stuff I am sure I have the same look

[Sprinter]

For high mass slabs when used for heating, a 10 degree DT is recommended for even floor temp. Depending how it's piped and what the Cv value is for the mixing valve, the 007 is probably shy even at DT20. If the 007 is right on the mani and a low loss MV , Its 10' head@ 1 GPM @ 120* and 3.5' @ .5gpm. It's ok if its idled or you don't expect a quick recovery time.  You can see what it does by closing 3 loops and testing DT from there. Sounds like some fine tuning. I run as low as 90*, but insul and soil conditions play a very big role. And as high as 140 if the flat men didn't do a good job on the mesh chairs. I'd rather see increased flow before higher temp if possible.

[willieG]

here is a shot of my single floor loop and its circulating system

pump is pushing water down..top left is return from floor..bottom left is feed into floor..top right is hot OWB water in and bottom right is return to OWB

after checking on the little pump i find it is running between 1.5 and less than 2 gpm

[slimjim]

Willie, what's the zone valve about?

[idahohay]

Also wondering about the zone valve.  If it closes, does the rest of your system get increased flow? And would the water still continue to circulate in your floor loop?

Thats a cool use of a Watts M-series Isotherm kit. Apparently the new setups are the same in stainless.
( just searched and the Isotherm is the same, the manifolds are in stainless)

[willieG]

lets see if i can explain...the zone valve is controlled by the  wall thermostat...when the room is satisfied the circulator circulates through the zone...this ensures a pretty much even temp through out the floor as the water is always moving so there are no "cold" spots. the pump is punshing down so the water is coming from the top left  pipe (out from floor) and ging back in the bottom left (into floor)  when the room calls for heat the zone valve opens and now water that is being pulled from teh floor loop is pushed down and at the same time  some new water is added from the  OWB line, this water is mixed with some of the cooler floor water by it being pushed (and/or sucked) up the "cold: inlet in the mixing valve. what ever comes out of the floorloop MUST go back in and floor water that was replaced with hot water from the OWB feedl ine now goes out the zone valve and back to the OWB

i hope this kind of makes sense..i may not be real good at  describing it but it works

as for increased flow..i guess so...i have a manifold in the house that is fed from my taco 11 and it services this floor loop, the water to air exchanger in teh furnace and a small rad in my fire place and the home made tube and shell for the doemstic...the domestic (3/4 copper) and the fireplace water to air (1/2 pex) are both circulating 24/7 so is uspect when the floor loop kicks in those things sufffer the loss while the floor loop is running..i have never seen any downfall from this

[Clueless]

Yeah the slab is good and warm, took a while. Inlet at 110 -120, outlet at 70 (ambiant room temp). I'll be shutting it down soon, and this summer gonna tackle the mixing valve. I will also get in touch with the people who did the install, should be some documents or prints.

Now for the summer, should i drain it? Leave it full? Any tips on summer mode would be of great help. Thanks again for your input...i also have some treatment for the water, whats the ratio?

Cheers!

[slimjim]

Sample water sent to corporate for testing and don't drain it