How long for slab to warm up?

[HiItsMeJimmy]

For you guys with a well insulated larger slab from a cold start how long for slab to get up to temperature?? 12 hours?? 24 hours??

 

[anthony666]

how long is a piece of string ??

depends on so many variables; starting temp, design temp, insulation, mass of slab, tube spacing, ground water, etc etc .. typically a small properly built, well insulated, dry slab might take only a few hours .. whereas a large badly set up system with ground water leaching heat might never come up to design temp

some larger well built systems ive done took 2 or 3 days to slowly warm through the first time

 

[mygarageone]

how long is a piece of string ??

depends on so many variables; starting temp, design temp, insulation, mass of slab, tube spacing, ground water, etc etc .. typically a small properly built, well insulated, dry slab might take only a few hours .. whereas a large badly set up system with ground water leaching heat might never come up to design temp

some larger well built systems ive done took 2 or 3 days to slowly warm through the first time

Like you stated to many unknowns , No way to answer .

 

[5mall5nail5]

how long is a piece of string ??

6 or 7

 

[HiItsMeJimmy]

Building is 40x64x14
R-30 in ceiling with 6 inches of open cell on walls
2" XPS under 6" concrete perimeter insulated as well
8- 1/2" -300ft. runs 12" spacing, 6" around perimeter with adjustable reising manifold.
180000BTU Hardy outdoor wood burner with 45% glycol
3 insulated 12x12 doors
OO9 circulator pump at boiler and 009 circulator at manifold
1GPM through each circuit
3/4 feeds from boiler
Honeywell Mixing valve @113* Return water 83*
Radiant thermostat WITHOUT floor probe.:

 

[mygarageone]

Building is 40x64x14
R-30 in ceiling with 6 inches of open cell on walls
2" XPS under 6" concrete perimeter insulated as well
8- 1/2" -300ft. runs 12" spacing, 6" around perimeter with adjustable reising manifold.
180000BTU Hardy outdoor wood burner with 45% glycol
3 insulated 12x12 doors
OO9 circulator pump at boiler and 009 circulator at manifold
1GPM through each circuit
3/4 feeds from boiler
Honeywell Mixing valve @113* Return water 83*
Radiant thermostat WITHOUT floor probe.:

Well , it again depends on when you fire the system up , if the slab temp is really cold a few days if the slab temp is not so cold a couple of days The water temp makes a difference , and on and on we go.
Either way it will take a 2-3 days . May I ask why this question ?
Also if you have temp gauges on the supply manifold and one on the return manifold , you will know if heat is being released by the temp difference. If that be the case . you are heating the slab.

Is the system actually in operation ? If so how do you know about your supply and return temps ?

 

[HiItsMeJimmy]

Let system run for 12 hours and not much change in temp. Guess I need to fire boiler and let it eat!!

 

[mygarageone]

Let system run for 12 hours and not much change in temp. Guess I need to fire boiler and let it eat!!

DUH , Ya that would be a good idea !

 

[Rockhead261]

Let system run for 12 hours and not much change in temp. Guess I need to fire boiler and let it eat!!

Clarification, please. Was the boiler running for those 12 hours?

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[mygarageone]

Clarification, please. Was the boiler running for those 12 hours?

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His message said , guess I better fire the boiler .

 

[HiItsMeJimmy]

Yes it was running

 

[HiItsMeJimmy]

I have a reifing adjustable manifold. Some supply lines feel warmer then others even though flow through each circuit is identical. Gonna shoot it with them gun and see where I'm at

 

[mygarageone]

I have a reifing adjustable manifold. Some supply lines feel warmer then others even though flow through each circuit is identical. Gonna shoot it with them gun and see where I'm at

Does your system have an air purge ? Even if you initially purged the air , you will have more air as the water heats up , and that could also contribute to a no heat or slow heating system.
The other thing , crank up your supply temp to 120 or 125 until the slab gets up to temp and drop it back down to 115 if you want to.

How about some pic's of your system . maybe there is something piped wrong or who knows.

 

[HiItsMeJimmy]

Have a closed system without outdoor wood burner, didn't think I needed an air purge.

 

[pantera1]

From a previous post, thought you had a Hardy outdoor wood boiler?


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[HiItsMeJimmy]

True I have a hardy outdoor burner

 

[pantera1]

I see that now! Dang new to me Tapatalk app.

 

[HiItsMeJimmy]

The runs that are cold if I shut off return valve on manifold feed pressure does not decrease but stays at 1gpm. The feeds that ate hot if I shut off return valve my feed pressure drops. Any ideas???

 

[mygarageone]

Have a closed system without outdoor wood burner, didn't think I needed an air purge.

Well what else are you missing , post some pic's after all you've done there something amiss. Can't trouble shoot with out pic's

 

[pseudorealityx]

GPM * 500 * [supply temp - return temp] = how many BTU are being fed into the slab.

 

[mygarageone]

I would also suggest you prove one loop at a time , shut every loop off but one, this should help create positive flow but again if you do not have any sort of air purge on the system , you may be air bound and that' will prevent flow . pumps can not most times push water past an air pocket.

The biggest problem we are all having is , guessing how you installed your system ,
With out some sort of picture . we have no real idea what you have there .

 

[anthony666]

didn't think I needed an air purge.

as the system ages the oxygen dissolved in the water will be released .. you need a way for that air to be expelled from the system or you just wasted a lot of money/time/effort for nothing

fix it stat before one us comes over and slaps the tar out of you

 

[tdkkart]

Since nobody has seem to answer your question, my system raises my room temp about 1 degree/hr of run time. 1/2" tubing on 12" centers, fed at approx. 100degrees and dropping approx 20* from input to output. Heating 30x40x12. I fired it up last week, initial warmup brought it up 10* and ran 9hrs to do it.

 

[rclassic]

Last night I filled the system, bled the lines and plugged it in, the temp on the heater is set at 120 the pump is on low speed moving 1.6 gpm,the return temp was 46F and floor was 50F. I left it run for 1hr. just to check and be sure everything was OK.
When I turned it off the return was 63F and floor was 54F.I am going to wait until I have a day off to start it for the winter,I'd like to watch it for several hours.
Should I leave the pump at 1.6 gpm or bump it to med. (2.4gpm)? The heater sounds like its just idling @1.6 and a bit more of a roar @2.4 and the temp. setting 120F? Just leave it alone until the floor heats-up?

 

[mygarageone]

Since nobody has seem to answer your question, my system raises my room temp about 1 degree/hr of run time. 1/2" tubing on 12" centers, fed at approx. 100degrees and dropping approx 20* from input to output. Heating 30x40x12. I fired it up last week, initial warmup brought it up 10* and ran 9hrs to do it.

We gave him all kinds of answers and have ask repeatedly for his system pic's and we get nothing. .

Can't fix anything when you have no idea what your dealing with !

 

[HiItsMeJimmy]

Played with system after work last night. The manifold has adjusters for each zone. I had adjuster turned clockwise to increase flow. Shot feed with temp gun and temp was 80s. Temp gauge on main feed is 120. For some reason when I had adjuster turned clockwise it shut flow off. Opened adjuster all the way counterclockwise and let system RUn for 8 hours. I had floor temp of 72. Garage was very warm. Tried to find manual for my reising. (Spelling?) Manifold . Looks like they are discontinued. Might be a reason why!

 

[anthony666]

fyi; those guns don't work properly on any kind of reflective surface .. ie, pex, copper etc

 

[mygarageone]

Played with system after work last night. The manifold has adjusters for each zone. I had adjuster turned clockwise to increase flow. Shot feed with temp gun and temp was 80s. Temp gauge on main feed is 120. For some reason when I had adjuster turned clockwise it shut flow off. Opened adjuster all the way counterclockwise and let system RUn for 8 hours. I had floor temp of 72. Garage was very warm. Tried to find manual for my reising. (Spelling?) Manifold . Looks like they are discontinued. Might be a reason why!

Just because it was discontinued does not make them bad , they may have only quit making that model .

I do not think they are the problem. It stems from what you did or didn't do or don't understand.
You installed a system with no purger and said you didn't think you needed one , that makes me wonder what else have you not installed that you should have .
Who knows where you have the circ pump located ? that could make all the difference in the world.

I have installed many , many floor systems and it's never taken me more than a few hours to have the system up and heating the slab.
My own garage was fired up in the middle of Jan with no freeze protection and I had absolutely no issues at all. It now has Glycol

 

[HiItsMeJimmy]

Why would I.need a purger when using an outdoor wood burner. I assume since boiler has vent it would be pushed out system and bleed through wood boiler. I have an 009 at boiler and 009 after mixing valve right before manifold inlet. Went off wood boilers instructions for hooking a radiant floor up. Seems to be working good now that I'm getting flow through all circuits. Should slab temp be 5* greater then desired room temp?

 

[pantera1]

My floor also runs 5 F warmer than air temp. A buddy with an on demand boiler also runs 5 F warmer at the floor.

You don't need the air expansion tank if your return is going back out to the stove. The stove is vented already. Now, if you were running the floor water thru a heat exchanger, one would need an expansion tank.

Doesn't seem to be many of us using an outdoor woodstove to heat the floor. Most peoples reference point is the boilers that get hung on the wall. There seems to be a lot more plumbing involved.

Sounds like you've got it all sorted.

 

[Jackfre]

Why would I.need a purger when using an outdoor wood burner. I assume since boiler has vent it would be pushed out system and bleed through wood boiler. I have an 009 at boiler and 009 after mixing valve right before manifold inlet. Went off wood boilers instructions for hooking a radiant floor up. Seems to be working good now that I'm getting flow through all circuits. Should slab temp be 5* greater then desired room temp?

Air can lock up a system like you would not believe. It is one of those things that can recur to darken your mood. Perhaps you don't need a purge set-up, but life is so much better with one. It just makes the system easier to start up and service. I second the motion to purge one loop at a time with the others closed off.

 

[koditten]

fyi; those guns don't work properly on any kind of reflective surface .. ie, pex, copper etc

I agree, different surfaces create different temp readings. I solved this by placing a piece of blue painters tape on every location that I wanted to read the temp.

Gave much more believable readings.