I think the guy's desperate to make a boat payment.

I had a free loan of the tool you are talking about. I used it in the very beginning.

Then I found a 'cinch ring' tool at Lowes (= Home Desperate) for $35.


After I used the cinch ring tool, I never picked up the crimp ring tool again.

I then did the whole house with the cinch ring tool and had zero leaks. I did have 1 leak from a crimped ring.

-AC_Hacker

In researching best insulation for below "pex in slab" install high density rigid closed cell foam boards seems to be the leader. But hydronic heat being "radiant" most of these foam sheets have no reflective foil component. Would adding a "foil" between foam board and poured concrete be something to consider to help contain heat to slab/heated space? I know there are foil faced rigid foams out there but they aren't best for below ground application.

Radiant barriers require an air gap to work, so no. Using foam is fine. Since the foam is touching the concrete, there is no radiant heat. It is all conductive heat, and the foam doens't conduct heat well, so it won't escape through it.

So the greater the NON-"conductive" insulation the better for heated grade slabs?

I think I figured it out - he could make a
boat payment for what the battery operated
tool costs.

Someone mentioned the ratcheting
cinch tool, and they did have it at
Lowes (or HD, it's all a blur).

It's more expensive than the pliers-type
cinch tool, but it's one handed
(and includes a free LED light
to say when it thinks you are done. :-)

I made all my "cinch"es - 2 each for 12 loops,
and 2 each for the 4 manifolds and the plugs.
HD sells a pressure test kit. (Lowes does not
sell it, or just doesn't know they do :-).
I'm still working on compressor plumbing
issues, so I used old reliable - Nashbar bike
pump. The first floor holds air, the second
does not.

I'll let you know.

It's like day and night....
 

Today, the daytime temperatures around here were insane (if I read correctly, nearby Newark broke a record)....but the temperature after dark was 65.

It seems to me that something could be done
with one or more buffer tanks to "save the heat"
for later on....when cooling it down should be
cheaper....and then "pre-chill" some water
in preparation for the next day.

Ideally, it would be nice to have a simple
design that "just works," but other options
would be 1. a person looking up the forecast
and setting it up or 2. The system looking at
the forecast....


My brain went into overdrive today
in Synagogue, as they have big 220/15amp
units (one per classroom)....and the forced air
system connected to the furnace is idle.
Only 2 AC's were on, and the rest of the
building was a steam bath.

One idea would be to lay ground loops
on the surface or shallow...in a crawl space
under the building. The building rests on
piers, like an elevated pole barn.

If the pipes were actually on the surface,
we would need to do something about
moisture. We would not want any to
penetrate the floor above the crawl space.

pressure testing
 

I discussed the pressure testing issue with my friend,
and (I should stop being surprised) he guessed
right away - the radiant pipes are fine, the
pressure test fittings don't hold air so well.

I installed a ball valve in front of each pressure test
gauge. Once the pressure is up, I close the valve.
The valve is only open for brief observing of the
pressure, but not overnight.

This also allows me to pump a circuit up to 50 psi,
and disconnect the gauge/schraeder valve,
go do the next circuit, and then switch
back and forth as needed to check.

Overnight, neither circuit lost pressure.

The next pressure test will be the one circuit
I ran. The contractor happened to need to take
down a ceiling during renovation, so on Sunday
I jumped in and installed one circuit - including
plumbing it down to the basement in a new
wall. It's *much* easier with 2 people,
but not impossible with one.
I did not have time to use the angle grinder
on existing nails, so this pressure test
definitely has me nervous.

Radiantec recommended pinching the heat
spreader plate so that the pipe is dropped
down away from the nails, but there is
still a risk from installation carelessness.
I'll report. (Ceilings might well be closed by
the time I get home :-)

Now I am shopping for a case of 1/2" pumps.
Need to check the charts for flow needed.


Note - HD sells a pressure test kit that
goes up to 30 psi. My plumber's kit was
up to 100 psi. buyer beware.

Question for Ko_deZ regarding radiant floor (continued)...
 

Ko_deZ,

(NOTE TO READERS: To follow this discussion properly, please start here.)

I would like to see what your thinking is regarding radiant floor construction, for low-temperature heating, such as GSHP and solar...

I have several questions...

Here in the US, fossil fuel is still pretty cheap, compared to the rest of the world. This has a big influence on how radiant floors are designed. The usual assumption here is that a gas-fired or oil-fired boiler will be used, and the design ideas flow from that assumption.

For instance, PEX spacing is almost always 12" on center, with maybe 9" on center being the exception. My impression is that European standards favor much closer PEX spacing (6" or maybe less?), and therefore lower feed temperatures, and higher efficiencies.

I would also be interested to know what your thinking is regarding high-mass radiant floors and low-mass floors.

I am going to put in a radiant floor this summer. I found a product that looks to be ideal that has channels cut in oriented strand board for the PEX and has .025" thick aluminum bonded to the surface. The problem is that they only do 12" centers, which I would like to improve on.

So I'm trying to solve the close-spaced PEX problem and also get very high thermal conduction.

I'm not very confidant that my old house would be able to hold up to the added load of even a thin concrete floor.

Any discussion would be appreciated.

-AC_Hacker

AC,
In my under-floor (staple-up), I used 8" spacing for my 1/2" PEX from Radiantec. They recommended 2 pipes per joist cavity, and they are on 16" centers. When I do the old part of the house, those are on 12" centers, so it will be 6" centers mostl likely.

(actually, I already did one small room where the ceiling below had been removed.) Because I have the soon-to-retire gas boiler as a backup, I did not worry about some joist cavities that only had room for 1 pipe.

My guess is that can be helped by using slightly shorter loops,
so water temp will be at the upper end of the range for the system
when it hits these pipes.

Good luck everyone. Will post pics when I can, and report when
the heating season starts.

Hi all. Ok, I will dive in here as well. I had a rather elaborate post in another thread, maybe you could make a link to it AC? I don't think I can insert links yet.

EDIT (Piwoslaw): Here is the link:
The Homemade Heat Pump Manifesto, post #808

Anyways, here is an explanation on what I said about floor heating being "self adjusting".

The effect of self regulating comes built in to the whole floor heating system. If you have a system that can supply a steady input temperature to your loops that is, and that the floor loops are not too long. Never push the lengths of the floor circuits. It is not obvious unless you think of it in the correct way. I will try to explain more in detail.

Let's use a normal concrete floor as an example. A floor like this will keep an almost fixed temperature if fed from an adjusted source. With adjusted source, I mean that there is an accumulator tank that has a higher temperature than the input at all times, and that the circulating water is mixed with a varying amount of water coming from the accumulator to make the feed water temperature very stable. Given that the input is very stable, and the loop length is not too long, the floor will stay very close to a constant temperature no matter how much heat it delivers.
As a theoretical basis, we will assume that the floor is constant temperature. Given this, we also know that the air temperature in a room with floor heating is quite close to the temperature of the floor, in this case we assume 20C floor temperature. Now, if the difference between floor and air is 1 degree when the outside temperature is 10C. Calculating the heat provided from the floor, you use this delta temperature in a formula that would look something like p = floor_area * heating_capacity_constant * thermal_difference. The first two does not change for a fixed room. So if the temperature drops to 0C, that would increase the thermal loss trough walls and ceiling and everything, reducing the air temperature, let's for the argument say that it is almost linear and that it now becomes 2 degrees difference from air to floor. What happes to the p above? It doubles. The floor will now release twice the amount of energy. Yes, the water leaving the floor will be ever so slightly colder, but the system adapts to that so that more heat is grabbed from the accumulator. This means that the temperature has dropped 1 degree in the room as a result of 10 degrees drop outside. If it drops another 10 degrees, there will be another 1 degree drop inside. Not a significant drop.

Comparing this to a system with 50degree radiators, a drop in temperature from 10 degrees to 0 degrees outside would demand the radiators to deliver twice the energy to keep the temperature up. The formula for delivered thermal energy would be about the same as above, but the difference would go from 30 degrees to 31 degrees. That would not double the P. Therefor you need to have each radiator or room thermally controlled via some regulator, which pretty much all radiators have. Heated floors does not need that, because of the huge area and low temperature difference between air and floor, an increase in temperature difference makes a huge impact on the amount of energy it provides. Many will try and sell you these wireless controllers that you should use for each room. That is imo a waste of money. If you can make the mixing temperature from the accumulator go up and down a degree or two based on the general indoor temperature, that should keep the whole house at a pretty steady temperature. This is why i say that it is self adjusting. It is this way by design. Now, some floors are not so efficient as a concrete floor. If there is a layer of wood or so above the tubes, the adjustment of the mixing temperature should certainly be done as the indoor temperature drop could be several degrees and change the temperature outside the comfort zone. Dispite this, the difference would be a lot smaller than an unregulated radiator system.

Regarding the spacing, this depends on a couple of things. Most floors here are made of wood. Solid, parquet (most people have this) or laminated. We have very few homes with a concrete floor, except for the basement that is, but usually we cover this with wood too. We are 13 persons per square kilometer, and we have loots of forrest, so pretty much every home is made of wood materials, from studs to floors and roofing. Top roofing is usually stone tiles of some sort, or dutch clay if you have the money for it. Anyway, as we usually have a wooden floor, and the beams are wood, and we usually have an under-floor of 22mm chipboard or similar, we lack the heat distributing layer that a concrete floor gives (we do use concrete on top of the 22mm chipboard if we put tiles, like in our bathrooms). So we use heat spread aluminum plates. The most popular brand here is uponor. There are two main dimensions used, 20mm and 17mm. The 20mm can be pulled for 120meter or so, while the 17mm should preferably not be much longer than 80m because of the reduced waterflow. Also, the heat spread plates are not as wide with 17mm, so that makes the area it can cover about half of 20mm. The bonus though, is that there will be less local difference. The thermal energy does not have to move so far from the tube to get to the center between two loops, making sure that you don't get the situation that your toes are warm and your heel is cold. Most installers use 17 wherever they can, but 20 in concrete. 6" equals to about 15cm. That seems to be close to the 20cm that our 17mm system uses. There is a gap of 10mm between the heat spread plates to avoid them making sounds, and the heat spreaders are 190mm. The 20mm is spaced about 30cm (12 inches approx I guess). There is a point that the efficiency is higher with a better heat spread, but it does not solely depend on spacing. How you spread the heat is also important. If you had a perfect heat spreader, you could easily get away with only one straight tube and a huge heat spreader, efficiency then should be phenomenal.

The product that you mentioned is also sold here, although it is not widely used. The reason for this is that placing something like that, you would have to protect it to avoid damage to the heat spreader while constructing, and that is unpractical. Placing heat spreaders manually goes quite quickly. You either get some flooring with channels cut into them for the tubes, or just make your own. Just ordinary pieces of wood paneling, cheapest sort should do. Fix them to the floor with just enough spacing that the heat spread plate with pex in it fits in the gap. Put some cheap fabric in there to avoid squeaking. Most squeaking in heated floors with this solution is the heat spreader moving up and down slightly. The rest is usually due to not gluing your chipboards, not using screws but rather nailing them down, and not putting a fabric between the chipboards and the beams the rest on. Was it Vlad that did this already? You can drop the aluminum foil, as the reflected IR will to a big extent be reflected back down by the aluminum heat spreaders. It is not a worth the effort, but more importantly, it creates a diffusion tight seal that might be a cause of condensation issues if the area below is humid. A heated floor should help the problem, but it is not ideal.

My best tip here is to use heat spreaders of some sort. Aluminum is cheap and has a low thermal resistance as long as it is not paper thin. The ones you refer to has thicker aluminum that usually used here for 20mm pipes (0.6mm thick), so they should do just fine.