New Radiant Flooring Complete Install - Need Pro Consultation

edwardpitzul

Need help, willing to pay for your time! I have a newly constructed pole barn with an office and storage room ~3,500sf total. I installed 1/2" PEX in the concrete slab with 2" insulation pad. We have 13 lines and 2 zones. What kind of manifold should we get? Do we need two 8-loop manifolds? That's what we were thinking. We are wondering what kind of expansion tank and type of pumps and quantity to get. See our install below.

Next step will be setting up the manifold...or what is the next step? Contractors in our area (Clackamas Oregon) have limited know-how and we can't find anyone that is able to support. This is an owner-build project and we're working as our own general contractor. I need guidance on equipment, brands and materials, as well as opinions on boilers. What we have in mind is a waste oil boiler. Considering the Clean Burn CTB-200. Is this something that would be highly recommended?


Any professional advice on setup, equipment needed, install guidelines and diagrams is appreciated. Please reach out to me in the comments and we can get on a phone call or email.

psb75

Looks like you'll probably need two 6 port and two 7 port manifolds. You have a total of 26 ports and it depends on how you want to divide the 13 loops into the 2 zones. You'll need a circulating pump for each pair. Uponor brand manifolds are very good. There are other brands as well.

hot_rod

For shops like that I like a simple copper manifold with valves to adjust the loops. You will need a 1” Pex to supply that many loops.

Waste oil is a very messy fuel to deal with. I installed a number of the CB 350 and some required monthly cleaning. It really comes down to the type of waste oils you try to burn. Some of the synthetics are tough to combust. Water, anti freeze, ATF, paint thinners all tend to get dumped into waste oil tanks😳

With two zones a buffer tank might be wise as those boilers are best running hot, full out.
I used a ThermoMax tank as a buffer which gives you heat and hot water.

edwardpitzul

@psb75 We were thinking 2 zones but could stay with just one zone if that makes it least complicated. We just wanted to add the 2nd zone later, as we will build a small loft. If I have 2 manifolds I’ll need a circulating pump? Any recommendations. Thank you so much for your help. 

edwardpitzul

@hot_rod how many loops would I need on the copper manifolds and how many manifolds? Our pex is 1/2 inch, so we would need 1” supply? Any links on were I would be able to find those?

We are going with the waste oil burner cause we can source the oil, but I’m hearing it get dirty and lots of maintenance. What’s your recommendations for a burner? What’s the most cost effective for a shop as electricity is spendy where we live. Thank you for all your help this means so much to us. 

hot_rod

A small zone like a loft will not be a good condition to operate that 200 boiler at. It will bang on and off every few minutes. It only has one speed, full speed ahead.

To size the pump you need to know, type of fluid, gallon per minute, and the head of the circuit.

So what size tube and how long are the loop lengths, is a starting point.

In a perfect radiant world, you start with a load calculation and radiant design. That would spell out all the info. Loop size and length, gpm per loop, pressure drop per loop, and the total for the pump sizing. Without some data it will be a guesstimate, trial and error approach.

Design info like shown below.

For example, 13 loops at .65 gpm per loop = 8.45 gpm, that is one number.
The size and length of the loop gets the head number. Then you have the pump sizing criteria. I'm thinking a basic 3 speed circ could work Grundfos 15-58 for example. Alpha 15-58 if you want a higher efficiency pump more suited for future zoning.

If you go with that boiler you need either a buffer tank, hydro separator, or a primary secondary piping, and the pump for the boiler that Clean Burn recommends. It may ship with a pump?
The CB manual may show some piping options for low temperature systems like yours.

So some decisions to make before you start buying components.

GroundUp

So the entire slab is supposed to be one zone, and the future loft would be the 2nd? Or you want the slab to be 2 zones (perhaps the office separate from the shop) with the loft being a 3rd? If the latter, how many loops are in each zone? That's what size manifolds you'll need. Typical manifolds do not exceed 12 loops so if it's all one zone you could do any combination that comes to 13 whether that's 6+7 or 5+8 or 4+9, etc. Frankly, more details are needed. I've got a little experience with that CTB-200 and you couldn't give me one for free, but it certainly could be used with the proper piping and possibly a buffer if you're splitting it into multiple zones. Most would utilize a propane boiler as a primary and if you're deadset on the WOB, tie it into the system as a secondary or vice versa. I'd be happy to discuss design options with you for a fee, but again, will need more details on the system and its desired usage.

edwardpitzul

@hot_rod Hello thanks again for all your help. Lets forget about the second zone as a loft. Just makes things that more complicated.

We will stick to one zone, the shop and office is all on one slab. We have 13 loops running under at about 350 feet each loop which is a total of 4,500 feet in loops length. The pex size we are using is 1/2.

We dont you mean "to size the pump we need to know what type of fluid?" Like the type of fluid for the boiler?

Should we rethink the CTB-200? Reason we wanted to go with this unit is that we would be burning waste oil that would cost us much as we have access to mechanic shops, but seems like a hassle verse other routes. Whats your recommendation on efficiency and cost in the long haul? Electric would super spendy as it up again last couple of weeks..

"In a perfect radiant world, you start with a load calculation and radiant design?" Where do i find those resources?

Thank you again

edwardpitzul

@GroundUp Thank you for getting back to me. To make things less complicated. We will forget about the loft, only reason i said something was i thought we could add something later but that doesnt make sense anymore. Everything is on one zone, one slab, roughly 3,500sq in size, shop, small office. 13 loops rougly 350 feet in length.

Can you tell me a little more on CTB-200? only reason we were picking this unit cause we were thinking we could get the waste oil for free from our local mechanic shops. Which would be nothing to almost free to heat our shop up. But we are not set on anything yet. Just seem the better option for the long run. Thank you Eddie

hot_rod

There is quite a bit to installing and running a waste oil system. You will probably need a double wall storage tank, large enough to store the oil. I’m not sure you can legally haul waste oil in your area, check that out. I doubt you would want to spill a load of waste oil in Oregon🤔

A gas or lp fired mod con boiler would be a nice system, clean, quiet and 90% efficient

Since the tubing is in place you will need to size around that. If you. Want to do a load calculation your self it would be easy in. A one room building.


There are a few radiant contractors in your area. I could ask my local rep for referrals. Not all the good guys advertise.

You could hire @GroundUp to do a design, or I believe he builds plug and play panels.

I,m guessing 20-25 btu/ sq ft, you have plenty of tube to move that load. Probably an 80 - 100,000 btu condensing boiler. You could zone the 3 rooms with a modulating boiler.

Another option, although fairly new to the market is an air source heat pump to heat the water for the tubing.

So first off what are the fuel options. Natural gas? Certainly LP or electricity.

If so what are the costs of the various fuels? Here is a site to compare them plug in 90% for lp or natural gas, use the electric geo volume for a heat pump option.

https://coalpail.com/fuel-comparison-calculator-home-heating

edwardpitzul

@hot_rod Hello, i will look into seeing all the regulation on Waste oil. Didnt even think about that.

If you would ask for some local contractors that would be awesome!

@GroundUp i will get with him on design options.

Fuel options are Electric (which has increased last month by 18 percent). Natural gas, Oil. Im assuming LP is propane? if yes its almost the same cost of natural gas.

Im assuming the air heat pump is electric?

Thank you again for all this info i cant thank you enough

hot_rod

Oregon may be in a sweet spot for low electricity rates. An electric boiler or heat pump might be a good fit. @GroundUp knows how to determine when electricity is the better option.

Go online and see if your utility offers off peak electric rates.

Some utilities in Maine drop down to 3 cents or lower for TOU rates. Ramp the slab at night, coast through the daytime hours. Or spend the waste oil money on a large insulated tank to store for peak power, if available

Alan (California Radiant) Forbes

Portland has a design temperature of 22F. Are your winter temperatures close to theirs or colder? Design temperatures are not the coldest temperature, but the coldest average temperature. You will need this number for your heat loss calculations.

Based on @hot_rod's input, I'd forget about the waste oil boiler. Too much trouble and expense. Any savings will be offset by annoyance level; what a mess. Go with a natural gas boiler if easily available, LP if not.

You store hops in the summer. What goes on in the winter? Do you need to keep the temps at 68F or can it be lower? If lower is OK, you still want the office warm, no? Good reason for at least two zones.

Heat loss calc's are important. What are the dimensions of the rooms? Length, width, height; how are the walls and ceilings constructed and how much insulation is there? Window and skylight sizes; double or triple glazed?

Do you have any pictures of the tubing before concrete? How far apart are the tubing runs? 12" 18" 24"?

At 350' per loop of 1/2" tubing, you're pushing the limits; should not be more than 300' max. It will be a good experiment. Pump selection will be important as you're flowing .8 gpm with an 8' pressure drop per loop to get 25 BTU/ft. if the tube spacing is 12".

As a young adult, I used to spend summers in Silverton working on a farm - irrigating and harvesting grass seed, sod and sugar beets for seed. Later on, I studied at OSU in Corvallis and spent a summer in Medford working in a pear orchard next to Roxy Ann. Lived with a preacher's daughter in Ashland. In the morning on the way to work, I'd stop by the local jail to pick up a guy to work with us in the orchard and then drive him back in the afternoon. He just couldn't stay sober. Great memories of a great state.

hot_rod

4500' of pex in a 3500 sq ft building is a good start. 12" or less on center?
That helps a lot for getting the btu's into the space. We see shops with spacing around 18" sometimes.
Your tube spacing will allow for quick recoveries and lowest SWT.

Pole barns can be a challenge to get a good edge insulation. Pay attention to that detail, it is a big loss area on a slab construction. Get a good, weather proofed 2" of foam around the edge down to frost level if you can.

GroundUp

I'd have a hard time believing that NG and LP are comparable in price per BTU, but then again I wouldn't be surprised with Oregon ;-P.

-One KW of electricity yields 3412 BTU (assuming electric boiler at 100% efficient)
-One therm or CFH of NG yields 95,000 BTU at 95% efficiency
-One gallon of LP yields 87,000 BTU at 95% efficiency

That makes:
27.84 KW per therm/CFH of NG
25.48 KW per gallon of LP

If your electricity cost is 9.8 cents per KWH as Hot Rod's photo shows above, the above multiplier would be used to compare price.
-$.098 x 27.84 = $2.73 per therm of NG
OR
-$.98 x 25.48 = $2.50 per gallon of LP

In my neck of the woods, NG was about $.70/therm last I checked (I think, it's been close to a year) and LP is about $1.90/ gal so with $.098/kwh power, electric cost per BTU would be about 390% higher than NG and 31% higher than LP. Obviously your rates will vary, but I'd be very surprised if NG was anywhere near comparable to LP or electric resistance. A heat pump may very well be a viable option, which will often run 200-300% efficient in your climate, bringing those numbers much closer together. Again I'd be happy to go over this with you using your local rates per unit and get a more accurate comparison, but the above should give a decent ballpark idea.

Regarding the WOB, my experience is that unless you're providing your own oil, the maintenance and upkeep is through the roof and quickly outweighs the savings of "free" oil. Most shops giving away their oil don't really care what goes into it- so the oil is always mixed with antifreeze, water, trans fluid, hydraulic fluid, dirt, bugs, grass, hardware, tools, rodents, and whatever else may fall into the drain pan. This requires filtering and possible water separation which not only takes a ton of time (in addition to the logistics of transporting your "free" oil), it is also very messy. You'd almost need a dedicated area to perform all of this work to keep it from spilling out into the rest of the shop space and making an eyesore. Some WOB are a little more forgiving with what you can run through them, but the CTB specifically is pretty finicky in my experience. I certainly see the appeal, but for me personally, the proverbial juice would never be worth the squeeze.

edwardpitzul

@hot_rod very good point! I will check with my electrical company to see if they offer peek hours discounts. That’s such a great idea of having a large insulated tank to preserve that water for the daytime. Is that like a large buffer tank. I’m so thankful for all you guys help. Don’t know what I would do with out you guys. I’ll be posting some pictures today of them pex tubing layout with the average weather here in Oregon. 

edwardpitzul

@Alan (California Radiant) Forbes I'm in the Portland metro area, so you can use that number for the heat loss calculation. It's maybe 23 degrees for a week out of the year. Below is an image of our average temperatures by month.

As for use, it's a hobby shop where we can work on projects. 68-70 degrees inside would be awesome to maintain throughout the cooler seasons. The radiant flooring is on a slab of 3,500ft, with an office and a small storage area. The ceiling height is probably about 24ft at its highest point. The bottom of the concrete is insulated 2" and the walls are insulated. The tubing is 12" apart. Photos below. It was typically 300' and 350' max (if that) for the length of each loop. What pump do you recommend?

Thank you.

edwardpitzul

@hot_rod everything is 12" or less, see images in post above. How did we do? We have 2" foam insulation so that should help?

edwardpitzul

@GroundUp thank you for all of this information here, we're doing all this research. Where we live we have one option for electric: Portland General Electric and one option for gas: NW Natural. We will call and figure out what the rates are for electric, gas and propane in our area. Because there's one monopoly, they aren't super transparent about pricing. I did find an interesting comparison chart using some data from March 2021 from NW Natural. See the PDF attachment. Can you elaborate a little more on the 200-300% efficiency? What does this mean if I have a heat pump - I am not familiar with this equipment. Is it a heat pump boiler? Electric boiler? Thank you so much.

GroundUp

They make water to water (aka geothermal) as well as air to water heat pumps, which can run up to 500% efficiency under the proper circumstances. Actual reality for ATW is probably 200-300% for the majority of days in your area. The upfront cost may be prohibitive though, depending what is installed and by who. An electric boiler would perform the same task, but at 100% efficient. Looking at those rates, even with 300% efficiency, NG would still be cheaper than heat pumps

Alan (California Radiant) Forbes

@edwardpitzul You ask good questions and @GroundUp has great answers. Keep it coming!

HomerJSmith

I didn't see you tube lengths of each circuit. For 1/2" tube, 250 to 300' is max per loop. For varying tube lengths, greater than 10%, I would use a balancing manifold. I like Caleffi's twist flow manifolds. How many ports on a manifold is dependent upon the supply piping to the manifold staying within the GPM of the supply piping. I would expect a flow of 1/2 to 1 GPM per loop. I assume one thermostat for the whole building. Use a pump that can overcome the pressure losses at the required GPM.
A buffer tank as suggested by @hot_rod should be a consideration.

Alan (California Radiant) Forbes

A buffer tank as suggested by @hot_rod should be a consideration.

For one zone, you don't need a buffer tank. If you decide to have more than one zone, that's the time to consider closely spaced tees, a low-loss header or a buffer tank.

edwardpitzul

@HomerJSmith I have 13 loops about 300feet each on the length on each. @hot_rod was saying if I was running a heat pump to preserve water on off peak hours, so I could store the water for the daytime. I don’t think I would need a buffer tank or insulated large tank if I end up going with Natural gas or propane as they run better and efficient at those lower temps. 

hot_rod

My thought on the buffer was either for a micro zone office that you mentioned.
Or if you wanted to store off peak power.