Is it enough?

[scrapart]

Ok so I'm one that uses what I have and what I have is a 15gal keg with ss fittings inlet out let
and a fitting to screw in a 120 heating element and a hot water controller and a taco pump with 50ft of 1/2 in pex and about 500sqft to heat .

I have noticed that I need to figure out a way to shut off the pump for when the liquid cools of so it can heat back up and I don't want to have to stand over the system to unplug the pump .

What can I do to improve my system with out spending an **** load ?

 

[930dreamer]

What are you trying to build?

 

[scrapart]

This is my infloor heat on the cheap.

 

[jimp]

What is the wattage on the heating element?

The biggest 120v elements I have seen are around 2000 watts.

Just a little bigger than one of those cheap resistance heater you find a Walmart. Don't think it's going to do the job, unless you live in Florida.

If you do make something out of these items, don't blow yourself up. Put a TP relief valve on the tank.

 

[StaggeringGoat]

the biggest 120v elements i have seen are around 2000 watts.

Just a little bigger than one of those cheap resistance heater you find a walmart. Don't think it's going to do the job, unless you live in florida.

x2

if you do make something out of these items, don't blow yourself up. Put a tp relief valve on the tank.

x3!!!

 

[Sureshot]

You would leave the pump run all the time and shut off the element on a thermostat. Infloor heat uses the thermal mass of the floor to moderate the room temperature fluctuations and you try to keep the entire slab at the same temp.

 

[scrapart]

What is the wattage on the heating element?

The biggest 120v elements I have seen are around 2000 watts.

Just a little bigger than one of those cheap resistance heater you find a Walmart. Don't think it's going to do the job, unless you live in Florida.

If you do make something out of these items, don't blow yourself up. Put a TP relief valve on the tank.

You hit it on the nose 120v 2000 watts. Nope don't and wont live in FL or any place that don't get snow I'm in the upper peninsula by Marquette MI.

So it sounds like I need to jump up to a 208/240V and around 5500 watts? What would be a good heater for 50ft of 1/2in pex with 500sqft to heat one line in and one line out ? Do they need to have pressure in the system in order for it to work?

Well its been put together for about a wk and I have been running it while out in the garage. I can run it for about 1/2hr to 45mins and then the coolant cools down to the point of I have to shut off the pump and let it heat back up.

 

[Sureshot]

You hit it on the nose 120v 2000 watts. Nope don't and wont live in FL or any place that don't get snow I'm in the upper peninsula by Marquette MI.

So it sounds like I need to jump up to a 208/240V and around 5500 watts? What would be a good heater for 50ft of 1/2in pex with 500sqft to heat one line in and one line out ? Do they need to have pressure in the system in order for it to work?

Well its been put together for about a wk and I have been running it while out in the garage. I can run it for about 1/2hr to 45mins and then the coolant cools down to the point of I have to shut off the pump and let it heat back up.

You will never get this to work on a short term basis like running it while in the garage. Leave the pump run and monitor the temp in and out of the unit and the slab temperature. You can't warm the cement by filling it with a small volume of warm water. The heating element has only the capacity to raise the temp at a certain rate. It takes the better part of 24 hrs for a system to "stabilize" with changes to the floor temp. Your undersized system will need to try to get the slab temp up during the day/warm period so it has hours of retained heat to help it in the cold/night.
I like to use the return temp of the water as my guideline to where my slab is. The difference between the water going in the slab and coming out of the slab will tell you how close the slab is to being stabilized. Write it in a logbook and learn your systems characteristics.
Is the space an attached garage? Insulated? Floor insulation? Lots of variables and starting from a weak point.
My system is "poor boy" by many standards. I do run a boiler but only use manual valves to mix the hot and return water to circulate back into the floor. My shop is well insulated and the volume of concrete makes the system work fine for me. The temp may drop in sustained -30 and -40 spells but compared to outside it is still great. During spring and fall I shut the burner off and on depending on the weather and shop temp. That saves me jacking with the valves which are "touchier" to adjust. Since it is very slow to heat up and cool in the building this works fine. I should put an air temp thermostat to shut it off during these periods of transition in the event the shop is getting too warm.
With your small heating capacity and volume you don't even need the "mixing" setup.
Keep your electric cost in mind.
It does not need to be pressurized and if doing it like you are I would stay away from even thinking about it.
If you are only going to run it only while in the shop get an electric fan heater and have it portable to blow on you and your work as needed.

 

[scrapart]

The space Im heating up is a 24x24 pole barn garage insulated with 2in pink on the walls, floor and a finished ceiling with some rolled insulation. Once I get the kinks worked out I plan on leaving it run....

 

[larry_g]

In the old shop I had ~250' of tubing, 30x36' shop, pole building with the 2" insulation and nothing under the floor. With a 4500 watt heater in the water heater I could maintain ~60f with outside temps of 25-30f. Just a data point. If I knew I had a weekend to work in the shop then I would turn on the heat Thursday and turn it off Sunday morning and the residual heat in the floor would keep all Sunday warm. I'm not sure what your 50' of tubing is going to do, it seems like not enough. I also would not stop the circulator.
Good luck

lg
no neat sig line

 

[scrapart]

Im seeing that you guys are running a lot of pex in a small area. I ran mine according to what I was told by the pluming guys in my area they told me that the pex should not be any closer than a foot to a foot and a half a part on the loops.

Well it is what it is I have 50ft in the floor and I'm just gonna have to deal with it. I ran the system yesterday and in order to maintain a good temp I had to turn the pump off once every hour for about 15mins to allow it to warm back up.

 

[wedge40]

It's the 50' of pex that I'm confused about. 500' would be closer to what is required. 50' would mean one loop in the concrete. Not saying it wouldn't work, but not very efficient.
Where/how is the pex laid out in the slab. You're leaving to much detail out of what you have set up. Right now my guess that's on purpose.
If you're pluming guy said this would work, I'd be finding a new plumber FAST!!!

With just 50' of pex, I'd make a radiator type heater. Oh wait you've already buried it in the cement. Never mind.


Wedge

 

[larry_g]

Well it is what it is I have 50ft in the floor and I'm just gonna have to deal with it. I ran the system yesterday and in order to maintain a good temp I had to turn the pump off once every hour for about 15mins to allow it to warm back up.

What doesn't compute here is the 50' of tube in a 500' building. 500' sq is near a 20x24' building. 50' of tubing would be just a U shaped loop, no serpentining of the tubing. Can you describe how the tubing is layed out in the floor?

lg
no neat sig line

 

[wedge40]

Red Green is that you?

 

[scrapart]

You're leaving to much detail out of what you have set up. Right now my guess that's on purpose.

Why would I leave information out when Im asking for help ? um lets see I have a keg with 3 fittings one for the heating element. One out port and one in port a 3in pipe connected to the taco pump connected to a 3ft pipe connected to pex. O Im human I made a mistake its 100' of what the wife has writen down. Its snaked back in forth one way then snaked the opposite driction on the other half.

 

[Sureshot]

Do you have a temp gun?
Why do you keep shutting the pump off?
Forget about the heater until the cement is up to the temp you want. It will have to run a long time if not forever to heat that pad. The water will come in the keg at x degrees and likely go out only a degree or two warmer but over time the inlet temp will rise and the outlet will rise accordingly. Leave it run until the slab is up to the temp you want. Do you want warm water or a warm slab??

 

[philjafo]

Do you have an expansion tank? A pressure relief valve? How bout a limit switch to shut down the heating element on the off chance its ever able to get hot? Maybe a backflow and fill valve to keep the system full of water? These are things needed for a safe hydronic heating system, maybe you should get in touch with a local HVAC company that can help you out because everyone on here said your setup is not going to produce enough heat and the relief valve has been mentioned, but it sounds like your missing all of the vital safety components. Please be carefull there is a lot of energy stored in water, if I knew how to post a link there would be one here for the mythbusters website, they disabled all the safety features on an ordinary electric water heater and its an awesome explosion.

 

[vartz04]

you need to shut off the pumps not the heater. the heater should have a thermostat that holds the water at the temp you want and then the pump circulates the water based on when a thermostat calls for heat in the garage.

My dad just has the attached garage on a manual valve, so the water heater always keeps the water warm but water is only circulated when you open the valve, the basement is powered by the same water heater but that is on a thermostat. The pump kicks on and off with the thermostats requirements but the waterheater always trys to keep the water hot.

if you can never get to the point where the water reaches a temp that will bring the space up to the desired temp then you need a bigger heater. quit turning off the pump and see what happens. If you can get the garage to the 60 degrees or whatever you want then get a thermostat for your pump.

 

[BigGMC]

What I'm taking form his expanation is that he's turning off the pump so that the homemade heater can catch up - warming the 15 gal capacity back to temperature (whatever that is, he didnt' mention cut out temp.)

He mentions that he turns the pump off once every hour for the heater to catch up. The part that red flags in my mind, is that it takes 45 minutes to lose the quantity of heat contained in only 15 gallons of water.!?! To me, this shows that there is not enough tube in the concrete - not enought heat is being transferred into the slab. I believe 15 gallons should lose its heat in just a few minutes.

50ft, 100ft..... not nearly enough to have an efficeint radient system. From what I've seen (and based on the kit I ordered for my application), most systems are designed with 1'pex per sqft. Some even go more as they like they like to do a couple runs spaced at 6" along perimeter of slab (since this is where most heat is lost). This is based on 1/2" pex.

Either theres alot more than 100' of pipe in the slab (which I doubt due to the heat loss issue), or the "plumber" is sadly mistaken on how radient systems work.
Another point to consider, how hot are you heating the water? Don't overheat the water thinking it will "push" more heat into the slab.... Pex has temperature limitations. A properly constructed system in concrete likes to run at lower temps, no more than 120deg

 

[JakeKohl]

Don't worry about the water getting cold in the tank...leave it running. The heating element is still heating the water and putting heat into the slab. That's why the water gets cold...it's heat is being transferred to the slab.

Like the other responders here, however, I believe you have cut a few corners that will prevent this system to do what you want it to do. It sounds like perhaps there is not enough PEX in the slab and not enough wattage in the heater...Also, hot pressurized water in contact with electricity in a metal keg can also be dangerous so make sure you have the proper safeguards in place to limit pressure and protect anyone from contact with the electricity.

 

[philjafo]

 

[wedge40]

We don't need no stinking relief valve.

Wedge

 

[scrapart]

My keg is not sealed! I did ask about it needing to be sealed in one of my other post. I also asked how Id go about sizing an actual heater.

 

[vartz04]

I did explain. Turn it on let it run and see what temp the garage maxes out at

 

[Full Throttle]

you can also use a small fryer burner, propane for frying turkeys and such. Set keg atop and use for initial warm up of slab to take some of the load off the electric element.

but for the money and time you have invested in this why don't you go buy a small Renni tankless water heater, or other brand

 

[scrapart]

you can also use a small fryer burner, propane for frying turkeys and such. Set keg atop and use for initial warm up of slab to take some of the load off the electric element.

but for the money and time you have invested in this why don't you go buy a small Renni tankless water heater, or other brand

Money wise including the pex, liquid, fittings, taco pump and heating element I have about 225. Thats a good I deal with the burner.

 

[Falcon67]

FWIW - If it does run all the time, at .10 /kWh you are looking at $5/day in power use more or less. For that space in insulation, probably a 45K propane heater and a tank will be cheaper before spring gets here.

 

[pseudorealityx]

If I was in the Michigan UP, and if I only had 2000 watts to put into the space, I'd put that 2000 watts really close to where *I* was working, not dumping it into the slab, and just call your "radiant flooring" a mistake and move on. It's not going to work, it's going to waste money, and it seems it's a safety hazard in it's current form, with little to no possibility of you actually making it 'correct'.

 

[jimp]

I also asked how Id go about sizing an actual heater.

65,000 btu's -- R19 roof, R11 walls on uninsulated slab without doors or windows.

For St Paul. Maintain 70 F in winter

5000 watts~ 17,000 BTU's, kinda small.

 

[Socophreak]

These types of kettles run about 10-12 lbs of pressure inside the steam jacket.