New garage time!

[fatjay]

This is the tubing I was looking at. I figure 2 spools of that will put me at 500' to spare: 1/2" x 1ft roll of PEX Tubing with Oxygen Barrier - PexUniverse

The manifold would be something like this to bring it together: 8-Port Stainless Steel Manifold for Radiant Floor Heating - PexUniverse

This is the hot water heater I liked: https://www.homedepot.com/p/EcoSmar...ectric-Tankless-Water-Heater-ECO-18/203316216

I was thinking of this pump: Taco 7-F5 Cast Iron Circulator Pump, 115V - PexUniverse

And this to control the pump: Taco SR51-4, 1-Zone Switching Relay - PexUniverse

So I can hook any old thermostat up. Plumbing this is going to be fun, I am looking forward to this one.

 

[ovrszd]

I'm concerned about the water heater. Not sure it can keep up. Your pump will run somewhere around 2.8 gpm. Your heater produces 3.5 gpm at 35F temp rise. You need your water temp to be 110 or so. If your water source temp is 55F and you are trying to heat it to 110F you have a 55F temp rise. Your heater won't be able to keep up with the flow rate of the pump and maintain 110F. You'll end up moving water that might be 80F. That won't work. It'll run non stop and never reach thermostat setting.

Understand, the heater does not regulate flow. If pushed beyond it's abilities it simply puts out water at a cooler temp.

You need a heater in this category. Not pimping the brand or model. Just showing you an example of the size you need.

Stiebel Eltron Tempra 36 Plus, Whole House Electric Tankless Water Heater - PexUniverse

Also, you need an expansion tank and an air burper. Depending on how you plumb it you may also need a one way valve and a pressure regulator.

Not trying to talk down to you. Just not sure what you know.

These systems work pretty simple. Thermostat demands heat, it activates the pump, heater sense water movement and fires up. When demand is met thermostat disconnects, pump stops, water movement stops and heater shuts off. The expansion tank is needed to handle the expansion and shrinkage of the water. Burper continually removes any air that forms thru the heating/cooling process. One way valve and regulator is needed if you want to create an open system that constantly has water service pressure against it.

 

[ovrszd]

Oh, forgot to mention pex pipe. You need a foot of pipe for every square foot of floor space in your building.

 

[ovrszd]

Here's a pic of my shop setup. Again, not pimping anything. Just offering ideas.

 

[aczlan]

I'm concerned about the water heater. Not sure it can keep up. Your pump will run somewhere around 2.8 gpm. Your heater produces 3.5 gpm at 35F temp rise. You need your water temp to be 110 or so. If your water source temp is 55F and you are trying to heat it to 110F you have a 55F temp rise. Your heater won't be able to keep up with the flow rate of the pump and maintain 110F. You'll end up moving water that might be 80F. That won't work. It'll run non stop and never reach thermostat setting.

Understand, the heater does not regulate flow. If pushed beyond it's abilities it simply puts out water at a cooler temp.

You need a heater in this category. Not pimping the brand or model. Just showing you an example of the size you need.

Stiebel Eltron Tempra 36 Plus, Whole House Electric Tankless Water Heater - PexUniverse

Also, you need an expansion tank and an air burper. Depending on how you plumb it you may also need a one way valve and a pressure regulator.

Not trying to talk down to you. Just not sure what you know.

These systems work pretty simple. Thermostat demands heat, it activates the pump, heater sense water movement and fires up. When demand is met thermostat disconnects, pump stops, water movement stops and heater shuts off. The expansion tank is needed to handle the expansion and shrinkage of the water. Burper continually removes any air that forms thru the heating/cooling process. One way valve and regulator is needed if you want to create an open system that constantly has water service pressure against it.

Except that if the water is recirculating in the system the temperature of the water coming in will rise as it brings the floor up temperature.
So in theory, the only temperature drop should be the amount of heat that the water gives up to the floor.
Definitely will need a check valve and a pressure regulator to prevent back feeding and drop the system pressure from whatever house pressure is set to.

Aaron Z

 

[ovrszd]

Except that if the water is recirculating in the system the temperature of the water coming in will rise as it brings the floor up temperature.
So in theory, the only temperature drop should be the amount of heat that the water gives up to the floor.
Definitely will need a check valve and a pressure regulator to prevent back feeding and drop the system pressure from whatever house pressure is set to.

Aaron Z

Excellent point Aaron. I forgot to factor that. I've never checked the temp of the water coming into my heater. Dang it, that would be good information right now. I'd guess that it will be similar to the thermostat setting or just above.

If it's really cold out my building is losing heat. So my floor will be warmer than my thermostat setting. I use a thermostat with a concrete probe. It detects both temps. Causes the system to run on shorter cycles more often which is good. I have my thermostat on 68F. The max concrete temp set on 75F. My probe is about 6ft from my manifolds. Really cold days it will cycle.

So if my floor temp is 72F (guessing) and my heater is on 120F (which it is), I'm warming the water 48F. Still exceeds his heater by 13F. Not going to keep up. At the end of a cycle he may be down to 80F or 90F water going into his loops.

 

[civilian]

Not sure if this is a factor in h OP's area, but our building dept will not allow water heater to be used to heat floors. It has to be a boiler system. Fuel or wood boiler. Just saying. Jon

 

[fatjay]

Finished parge coat, put on termite guard, got another 13 ton of stone to level it out and built a rake that will level the stone out. It sits on the outside 12's and drops down 2" where the stone needs to be.

Side note, I noticed a robin fly out of my backhoe. Turns out they built a nest in the boom.

 

[dragoneggs]

Mr. Fat, I continue to be impressed with your build and progress. Keep it going and keep posting the great pics!

 

[fatjay]

The $8200 for the floor is out. The guy wanted to do wire/pex sitting on the insulation, then 3x3 grid of rebar on top. Everything I researched said pex needs to be 1-2” from the top. So I’m doing 2’x2’ rebar on chairs at 3”, then wire on top of that, then pex ok top of that, which should put the pex about 1.5” from the top. Also priced rebar and wire plus concrete to come out to $3200, $5000 for a days labor for 2 guys is a bit much. I picked up the wire today and am picking up 60x 20’ pieces of rebar tomorrow. I have to decide if I want to do 6” or 12” spacing on pex because I’m going to tie it to the wire mesh and it’s 6” square. I know I’ll be putting in 2 lifts so I need to drill the concrete for anchors. So I’m thinking 12” in those areas, 6” in the rest.