Extruded plates - revisited (hb)

heatboy

RPA newsletter and once again this issue is brought up and raised my blood pressure. I try to be diplomatic as possible, so I will only pose this question to the author, who is the Western PA Wirsbo rep. How much radiant have you actually installed?

Warm Regards,

heatboy

"Expert in Silent Warmth"™

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John Felciano

Plates

I just read the article myself and have to wounder just how much radiant he's installed.He says he WAS the rep from 1988-1996 so I'm guessing he's no longer with Wirsbo.

He talks about the Ultra-fin.If I remember right that is a product that pop rivets onto the tubing suspended in the joist bays?Where you run the tubing perpendicular to the joists requireing about ten gazillion holes?Is that the same product or am I thinking about something different?

For me (a Holohan groupie)it will be plates on every job...

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Troy_3

Extruded plates

I'm with you guys. Staple up only with extruded plates. If you don't understand why it's cause I live in a 7000 degree day area. Don't promise the benefits of radiant and then short the job. If you don't use plates yet then you got some learnin' to do. As far as heating up my joist bays- my customers are not interested in warm air in their joist bays. They are living on top of the floor. A scorched air guy can blow warm air in the joist bay. If they wanted warm air they would at least put it where the occupants are.

Bill Clinton

plates or not

My Bona Fides: I've installed well over a million feet of tube over a period of fifteen years. I've done probably twenty suspended tube systems. They work.

That said, I don't know that I would operate at 180 degrees as the vilified author of that letter in the RPA newsletter suggests. I just don't trust what manufacturers claim, so I am dubious what fifty years of that temperature would do to the tube. My personallly established limit is 160 degrees. If more is needed, I would go to plates or supplementary heating.

If the point you guys want to make is that boilers are less efficient at higher temperatures, you're right. However, outdoor reset can make that a minimal difference.

Sorry guys, I repeat: suspended tube works. It works well in the right applications. I think your personal attacks on this guy are out of line.

Bill

Troy_3

Attack?

Bill: I'm not attacking anyone. There are many ways to get from here to there. With the design temps I'm dealing with my point is don't sell the customer a Buick and deliver a Yugo in a fancy dress.

Bill Clinton

sorry troy,

It wasn't your post I was referring to. I will argue with you a bit, however. You're right not to sell a Buick and deliver a Yugo. You're wrong if you assert that those who install suspended tube are doing that. The sole objection I have ever heard to suspended tube is that it requires a higher temperature to deliver the SAME performance. This means there is an upper limit to what suspended tube can deliver, and that plates can exceed that limit. Below that limit, however, suspended tube is a good option. ALWAYS provided the job is done right.

I applaud everybody's zeal for good quality systems and there certainly is room for different takes on this issue. The arguments, however, are technical, not moral.

Bill

John Felciano

Attacks????

I don't think I attacked Mr.Deane,I just have a difference in opinion and questioned just how much actual experience he has installing radiant,with or without plates.

The plate vs no plates argument will probably go on forever.And it's likely we all will never agree.

The way I see it, why put in a system that just barely makes the required load at a maximum temperature.What happens when Mrs. homeowner decides she HAS to have that big area rug and the suspended tube is at it's limit?

Noone is saying suspended tube doesn't work,it just doesn't work as well.If money were no object would you still do suspended tube or would you use plates?

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hr

But John


You said


"The way I see it, why put in a system that just barely makes the required load at a maximum temperature.What happens when Mrs. homeowner decides she HAS to have that big area rug and the suspended tube is at it's limit?"

You haven't defined the load! I found suspended tube CAN meet the load running 140 degree temperatures, lower sometimes for a simple warming application in a forced air heated room. I do agree plates are great, but I still agree with Bill identify the load and then make the call.

My Wirsbo desigh catalog shows 18 BTUs per square foot at 140 degree with R-0.5. Do you agree with that

hot rod

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John Felciano

I agree

there are aplications where suspended tube will work just fine.Floor warming is one of them as well as supplemental heat.It just doesn't make sense to me to not use plates on a stand alone radiant heating system.

I also think allot depends on how cold the winters.Here in Connecticut we design on a zero degree day.There have been many systems,even with plates, that use 140 deg water.



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Bill Clinton

hypothetical question, hr

Since the local Wirsbo dealer won't give me a Wirsbo design manual because I don't buy Wirsbo, I don't have access to that table you quote. Would you look up for me what kind of output Wirsbo says you can expect at 180 degree water temperature which all pex manufacturers claim is ok? I haven't been willing to go that high as yet, but what would you think of setting up a system with outdoor reset so temps would reach that high on only the coldest nights of the year.

And, John: how would you feel about an installer carefully informing a client that, during the coldest time of year, from 4 am to 9 am, in some parts of the house, the system might be able to maintain only 65 degrees and proceeding with their specific understanding of that? I've done that several times and everybody has been happy.

As to which I would use if money wasn't important; as usual, it depends. If I was comfortable with the performance I could expect from suspended tube, I would still incline toward it. If however, the customer wanted the absolute best performance guaranteed, I would spec plates. (then I would hire someone else to install the damn things:)

Bill

John Felciano

I realize

We may only see a handfull of days out of the heating season that goes down to design temperature.But I don't want that phone call at 3am from an angry customer telling me his house is cold after he just spent big$$$$$ on the best heating system money can buy.

Even if the customer was told up front and understood that he may not be able to keep his house at 70* 365 days a year.If you've been able to do that with some of your customers thats great,I take my hat off to you,but what about the guy that ends up in the house next?Will he be able to accept that or will he be telling everyone what a lousy heating system he has.

Just curios,what part of the country do you live,and what is your design temperature?

While I'm thinking about it, what do you use for a design indoor temperature?Everyone always talks about an inside design of 68* but I've found almost all my customers demand a inside temperature of 70-72*



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Dan Foley1

Design Temp

Interesting point, John. I have also been taught that you can design radiant systems to 65-68* indoor temperature. After getting burned a couple of times I now design to 70* indoor and "recommend" that the thermostat be set lower. -DF

Bill Clinton

Design temperature around here

is 35 degrees or so. I use 30 degrees and 70 degree indoor. The important figure after doing the calculation is BTU/sq ft., which is to some degree independent of climate: its a matter of building design. We do have some pretty large degree-day figures in San Francisco as the summer fog can make it one chilly place.

A consideration usually not figured into heat loss calcs (especially the low-tech method I use) is the heat gain from other sources: TV, radio, CD, lights, people, pets, cooking. Hell, my ex-wife claimed I generated 2,000 btu/hr just snoring!

In today's tight houses, these heat sources actually take care of a significant portion of the heat load. Add in that the maximum design load only occurrs for a few hours, and the flywheel effect of thermal mass (floors, ceilings, furniture, etc. and downward swings are shallow.

In multiple story buildings, only the top floor has to rely solely on the heat delivered through the floor. There is always some downward flow from the level above.

Only once in the twenty some jobs I've done with suspended tube has a customer complained about inadequate heat. That was one room on the top floor with three exposed walls, two of them almost solid glass and a huge skylight covering half ceiling. They put in an area rug too. I warned them they needed to let me put in a coupla radiators too, but they refused. I wound up simply telling them: "I toldja so!" They grinned and remained very happy customers anyway.

Bill

hr

Dan

A lot depends on the design software. Remember when the RPA compared a handful of design software programs with the same input examples!! I think some of the manufactures tweaked the good old Manual J just a bit too far for radiant.

Generally, now a days when a design falls short I've found the building itself doesn't match what I input or assumed. Learned that lesson again two winters ago (our coldest on record) Turns out the homeowner had all six!! fireplace dampers (8") open as well a huge exhaust hood over the Viking range. None of this was in the blueprints that I designed and bid on.

I suppose the only true way to do a accurate heat loss would be build the structure and run a blower door test. It's usually the infiltration, as you well know, that "throws a wrench in the works" Recessed lights and T&G wood ceilings will throw you a curve, big time, also.

hot rod

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heatboy

Personal attacks.

Bill,

To the best of my knowledge, I have only personally gotten ugly with one person who frequented the Wall back in the good ole' days. While he was deserving, I should have chosen my words a little more carefully. Even Ken Secor, who I disagree with on most things has a great deal of my respect because he walks the walk, as do you.

I question the motives of the author and I don't think he has lived it enough to tell me I'm doing it wrong.

Respectfully,

heatboy

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Troy_3

design

I agree it comes down to design loads. I would never be comfortable with tube running over 150 deg. in a joist bay personally. Not for the tubes sake, but for the sake of the floor joists, subfloor, finish floor etc. Maybe I'm too cautious but I don't want to be the next rubber fiasco. I met a TJI joist trouble shooter on a job and he said he is constantly explaining why their joists have been damaged by overheating. I want to be around for the long haul. Keep in mind, I am not in a moderate climate. We need heat not just a temperate floor. And I don't want a customer or the next owner of the house to say "we can't change our flooring choice because those guys that installed this system shorted us" They forget the good price but the complaining only increases. And yes we do lose those jobs where they say "just do it cheap"

Mike T., Swampeast MO

Damn boys...

...you're doing "Ford vs Chevvy."

NOTHING good comes of it as it's the same as fighting over religion.

Find your requirement for heat and design the system accordingly. Hydronics is so wonderfully versatile that there are often many ways to achieve the same result, yet something is ALWAYS compromised--be it cost, simplicity or longevity.

Debate is great but an activist is an activist is an activist.

Bill Clinton

My apologies, heatboy,

if I mistook your intent. Still, all the guy did was voice his enthusiasm for suspended tube and Ultra Fin (about which I am also dubious). He backed up his statement with a technical argument based on results from the KSU study. You didn't answer his technical point, but came back with questioning his motives and intimating he doesn't have enough experience to have a valid opinion. Even if you could give evidence this were true, it still seems to me you're trying to discredit the person rather than answer his point.

There was a famous lawyer in Rome at the time of Julius Caeser and damn if his name doesn't always escape me when I need it. He wrote a book on how to be a lawyer. One point he made: "If you don't have a case, attack the witness."

I'm not saying you don't have a case: all I'm saying is make your case.

Bill

Duncan

SAME performance?

From a comfort standpoint, yes... within limits (heat loss).

From a system efficiency standpoint, not likely.

I'm with Troy on this one. Probably because I'm an energy miser, and one of the commonly touted benefits of radiant floor heat is (was) low fuel bills. It's not there with the high temperatures and poor heat transfer of suspended, is it?

A VW with a 427 riding on 10 inch wheels vs. a Honda Accord.

hr

180

is a bit rich for my blood also. Keep in mind 180 inside the pex tube doesn't mean the joist will get that hot. Ken has made us all well aware that pex is an insulator! To a point that is true when compareing pex top copper.

Grab a piece of pex with 140 degree water flowing, then try the same with copper! Better yet slam some copper in a strip of ThermoFin, on the floor of your shop. Dump some 140 degree F water to it and behold some instant transfer. Lying on the floor that T-Fin will do the limbo in a few seconds:)

Wirsbo has 27 BTU listed for 180 supply under 3/4 plywood with R.5 value.

hot rod

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Larry Larkin

Just to set the record straight...

heatboy-

I work with the company (Thermoflo Equipment Company) that represents Wirsbo in Western Pennsylvania. I think the author in question mentioned that he WAS (pointed out by John Felciano) the Wirsbo rep at one time.

You might want to address your question directly to the author of that article. Thanks for the free publicity!

Earthfire

heatdamage

Was the t/joist guy talking about radiant systems damaging the joist or 180 deg. + bare m copper nailed to the joist from the cheaper fintube systems or the undersized, uninsulated overheated sheetmetal that the builders laborers installed on the cheap right against the joist,or the bvent that doesn't have the minimum clearance to the combustible joist. Constant up and down temp changes will stress any material (exp. work hardening of metal) and elevated temps can weaken glue.If the joist makers are having glue problems from constant temp from properly designed radiant systems they need to fix their glue problem. If the joist can't survive a radiant system with fairly even and constant temps. How the heck can they survive in the real world of uneducated and uncaring Builders that use them because they are a cheaper alternative to beams and bearing supports and also cut cost on installation of all the" nuisance hidden things that noone cares about " until they don't work. By then that el'chiselo's warranty has expired or he is operating under another name. MY RANT FOR TODAY

John Felciano

With

a design temperature of 30*-35* I guess I might question the use of plates too.(I can't believe I just said that???)But for this northeast climate it's just too cold for too many days to make suspended tube practical.

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Duncan_2

Installation techniques.

Heat emitters should do just that. Wouldn't good practice mean installing heat emitters in the living space instead of in air-filled boxes whenever possible? Suspended tubing hanging in a joist space is essentially installing heat in an insulated, air-filled box.

While plates coupled to wood floors as emitters may not be as efficient as embedded, at least it's a step in the right direction.

I see it as a case of lousy, better, best. Or Yugo vs. Honda.

Troy_3

Joist man.rep.

His wordstomy customer were"Oh good your heating contractor did the system right. He put the heat on top of the floor so your floor system won't dry out." His words not mine.Although you can be sure I was glad I didn't try to tell him it works just as good to just hang some tubing between those fancy joist of yours. I would have been sued for sure. This rep claimed the majority of the problems he looks at are from underfloor radiant jobs. I have not heard much talk of this or warning from any joist manufacturers so I was a little surprised. I figured it would take longer to show up. So where is the limit? Is there a legitimate concern? Inquiring minds want to know!

Duncan_2

I saw you say it!

John, I became involved in a project too late to pour a thin slab, had to use plates under a 3/4" plywood subfloor with a 5/4 glued and nailed spruce floor.

A homestead log cabin from the 1880s was moved log by log and rebuilt, and the owner wanted it to look authentic to the time period. Underneath was with 12" o.c. floor joist framing on a rock foundation and crawl space. I installed heavy aluminum plates and 3/8" PEX 6" o.c. It was the only way to meet the load.

The cabin is in the Tarryalls north of Lake George, where the cold, cold air creeps down the Tarryalls at night and settles in the valleys at 40 below sometimes. It gets 20 or 30 degrees colder than nearby hillsides a thousand feet higher.

I got a trouble call one morning after a 35° below zero night. Sixty-seven degrees below freezing. It kinda hurts if you breathe too fast. Exhaust from the sealed combustion boiler had frosted and iced over the 1/2" mesh on it's own stainless intake vent a foot away. The boiler was shutting down the more it tried to run. When I got there, the system was 70° and the house was about 65°. The wood stove was going, too. Toasty, really.

There were a lot of rugs on the floor, but the place was still warm, and the system was only 5° warmer than the room temp. I was impressed.