straighting out a system ,what to do?

clammy

I was asked to take a look at a radiant/ heating  system which was not performing when temps reached about 10 f and could not hold temp.There is 4 radiant zones 2 hi temp base and a idwh.2 zones are staple up with extruded plates and  2 in a slab.The staple up [late system that i was able to see did not seem to be installed correctly plates where 4 inch wide and screwed tightly to the sub floor except right next to the beams and did not run the length of the  bay ,they had left a 3 inch air gap and used r19 foil insulation and did not insulate rim or the end of the bays .The radiant in the slab was only insulated with bubble wrap and the back side of the home is a walk out .The staple up will not meet the lose and it seems while there that even after the slab is heated to about 78 and the boiler is running hi temp 180 when the slab is then turned on the boilers water temp drops to about 140 and will not recover no matter how long it runs but if i shut the slab zone and crank every thing up the boiler will get right up to 180 .Could the slab be sucking that much heat due to no insulation and causing the whole system to under perform .I did do a heat lose and the boiler is sized correctly but with the slab not being properly insulated the system under performs .Other reasons this system does not perform properly after 2 repipes by supposed pros is it still is not piped properly .Its a weil mclean ultra mod con 105 .The primary secondary was not piped correctly ,no outdoor reset nor indirect sensor .All radiant is done with fixed mixing valves and a pump piping arrangment that left us wondering who the hell did this they installed a pump on the mix port pumping away and another pump on the hot port pumping into the valve both wired to run at the same time .They had also installed the pumps for the hi temp pumping into the return while all the rest of the pumps are on the supplies and it seems when the radiant zones anre running the hi temps get no circulation until you shut off the radiant .All the piping is 1 inch and looks like a fool with no idea did  it even though these where supposly pro .I kinda feel that maybe the radiant can be used for floor warming but it will not heat the place when the femps drop to about 20  and we are planning to just load the place with either baseboard or panel rads.It seems from a couple of heat loses program sceanairos that the slab could be soaking away up to about 50mbtu to the earth what a waste. Am i on the right track or is there any better thoughts on this job it very sad that installer do not follow instruction nor take the time to install sysytems properly and of couse they have no answers or do they return  calls but they did i get paid and cash that check.What a sad state of afairs .Peace and good luck clammy 

Jamie Hall

You do have to wonder

where some of the installers we see are coming from...



Bubble wrap is great for shipping that precious vase back to your mother in law.  And not much else; I wouldn't be a bit surprised if that was where a lot of the heat is going -- particularly if the soil (I presume?) below the slab is moist or wet.  But there are so many other issues here...



Good luck!

Jack

for an assist....

Clammy, I won't try to help with the piping. I kinda met myself coming around the corner trying to understand what you are faced with there;) Something that may be of assistance to you however in demonstrating sealing/insulating methods to the homeowner is an article in the current Fine Homebuilding. Martin Holladay, wrote, "Air-sealing a Basement". It gives good details on sealing the rim joists. Good luck!

icesailor

Bubble Wrap: The Greatest.

Jamie,

I see that you just don't understand about Bubble Wrap. It is the greatest insulation on a roll ever devised for the Air Heads that have gotten into radiant. Years ago, I was told by one of them that 1/4" of bubble wrap was the equivalent to R-13 Fiberglass. Now, some air heads rip out insulated duct board duct and replace it with metal duct wrapped with bubble wrap. One was at the supply house trying to get a line on a new "double insulated" bubble wrap that you pull apart for the double insulation.

I gave up arguing because to do it properly, the cost goes through the roof. So, some "expert" comes along and puts a mess like this in. For some reason, I enjoy figuring out WHY the system doesn't work, and HOW to fix it. If it can be fixed.

The person asking the questions has done a very good job of diagnosing the problems. I would suggest to the customer to look into what I am saying to see if it is true.

I have a customer that has under-slab heating in his cellar. I turned it on and in two days, the water was barely coming back warm. It was flowing because the return was cold. I told him to turn it off and never to turn it back on unless he was willing to pay the cost of the LP fuel. He wasn't.

But the bubble wrap was the old stuff. Far better than 1" foam board that should have been used but wasn't. I guess.

Tim P._3

Look at the bright side..

They have a really nice vapor barrier.