Major Radiant Heat Tubing install error

Mark Woll_2

The lastest in the saga of the $270,000 residential addition heating fiasco...

Background:

1920's colonial, existing house converted gravity, near Philly, owner's added about 750 sf luxury kitchen, greatroom, mud room laundry room.

The heat is inadequate in the addition which received radiant tubing connected to the existing boiler.

Upon arrival, the heating contractor had misplumbed the radiant Taco 006 pump and Sparco which I corrected. Yet, he was seeing a problematic 30F or more Delta T on the two loops that were run for the addition. He just cranked up the Sparco to 140. Barely 100F water emmerged. I had them put in a B&G flowmeter on each to see what was going on, it never moved off the low end stop. Hmmmm.... we opened the purge valves, and closed one isolation valve, just a trickle came out.

I finally met with the heating guys this morning. They finally admitted that they ran each loop of 1/2 PEX in excess of 700'. No manifolds, no subcircuits, just two 700' loops from the basement panel.

This is all buried in gypsum concrete with a very expensive hardwood floor.

They finally admitted they performed no math and made no plans; they obviously were on their first decent sized job.

Guys, your solutions?

S Davis

Head Pressure

I had a job where they ran 1000' loops and then when it would not work we got the call, we put a pump on each loop and got lucky that we could deliver enough heat for most of the year, while keeping our velocities below 4' per second, we then added second stage heat with Tekmar zone controls.
I would start with your heat loss and see how bad off you are, how much flow is required and water temps and then just design backwards and see what you come up with.

S Davis


Apex Radiant Heating

Mark Woll_2

lets see .03 x 750' of tubing

gives us about a 24' head on each circuit. Which is far beyond the pump curve for that Taco

jp_2

4way valves

put in 4 way directional valves.

pump clockwise for 20 minutes then counter clockwise for 20 minutes to help balance out heat.

Jed_2

1000' Loops

I ran into a situation where the contractor was asked to heat a 7000' sq ft slab that the client had installed. A major sailing boat mgf. They isntalled 3 manifolds, 1 with 3 loops, and 2 with 2 loops. Each loop 1000' feet. Common supply pipe, paralleled manifolds. Contractor asks me if he can get any heat out. Not without base-mounted pumps, and destructive velocity. Over 400' hd. Heat loss was 300MBH+. They chopped up the concrete, and cut the tubing up to 250' lengths, then overpoured.

Jed

hr

I have exactly what you need

This flow reverser! It switches flow direction every 15 minutes. Paxton is considering marketing the 4 way valve with operator. I assembled it into this enclosure with a flowmeter for some testing.

Siggy hooked me up with the Paxton valve and we are doing some testing in my shop. I have 4- 200 foot loops which I can conviently couple together and have a sensor at the mid point (400 feet) as well as 200 feet from each end, to track the effectiveness.

I'm a little behing on the data gathering, been waiting for my slab to cool down more to load the system

Check this link for some info in the mean time.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,122299,00.html

hot rod



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Mark Woll_2

Siegenthaler article and a fight with the orig. installers!

The reversing valve is Brilliant. Brilliant. I will recommend such a fix. Nobody wants to jackhammer up the floor.

During the confrontation with the original heating contractor, it became quite ugly in front of the homeowner. I asked to see his tubing design and placement diagrams. He um..didn't have them with him. Did he actually prepare such a plan, um, he thought he did. I asked him which software he used, he couldn't remember, maybe someone else did that. He just ran the tube where he was told. I asked whether he reviewed trade technical materials which limits the lengths of runs of half inch pex to generally less than 300 feet per circuit. He wouldn't answer and started walking away huffed up. I stopped him. I asked whether he had ever calculated the feet of head pressure in 750 feet of pex. I asked whether he had ever seen a pump performance graph, he refused to look at it. So I put it in his face, and showed him that 25 feet of head at 2gpm was clearly beyond the limits of this Taco. I asked to see his heat loss calculations, I asked to see this, to see that, he had nothing and was getting beyond bothered. Then he started raising his voice: "What are you, telling me how to do my business?" "Who the F are you to tell me" "What the hell do you know" A heck of a lot more than you, how could you possibly run so much tubing?" Then he started raising his voice some more and straightening up in a menacing fashion.

At this point the homeowner was getting a bit antsy, and started trying to calm him down, "Mark's just telling you some things that you might have overlooked.." He walked him upstairs.

Overlooked, ha! These guys were the most incompetant fools I've seen lately. Clearly they had never done a radiant job before, or if they did, it was probably a very small one, nowhere near the limits of run length. They completely disregarded the manufacturer's literature and installation requirements (which were certainly never read) and they totally failed to perform required analysis.

These guys were true sewer hogs, and should never have been let anywhere near a heating system. What a disgrace to the trade.

hr

It's a fairly common

error with DIYers, also. I have "helped" a couple 1000'ers by just adding a 26-99. Not a perfect fix, but you will get some performance.

Forget about a Brute or 007, won't even get close

I had Siggy run some numbers on my last "fix" Came up with a flow of 1 gpm at 41.86 feet of head. Hard to find that pump!

With 12" OC in bare concrete 120°F at 1 gpm would return at 75° (44° delta T) and I did squeeze 21,000 BTU from the system which had a water heater as a sorce.

Siggy also suggested two 15-58 Super Brutes in series on speed 3 to get 38' at 1 gpm. Cheaper than a high head pump

I couldn't get the HDS to run that number, or my Radiant Works. But the engineers did God bless 'em

The customer is happy as a clam after hassleing the original installer for years. Claims he does 1000"ers all the time! Really I said, give me the address of those jobs

hot rod

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Mark Woll_2

Yes, the high head Grundfos will help, but I wanted to vent!

Dale Pickard

I think

Reversing the flow may help maintain some uniformity of temperature distribution between the supply tubing and the return tubing. A lot of that will depend on the layout.

However, if the flow is low, it really doesn't matter which direction it moves.
btu = mass flow x dt. If mass flow is low, you can only compensate with dt. If the tubing lay out is appropriate, you might change how dt is distributed through a room, but you won't increase btu. Low flow is low flow, pretty unforgiving.

Dale

Weezbo

Go under the gypcrete remove sheet rock ....

consult your "Crystal ball" tag the pipe cut it add a return to the boiler. you use best guestimate based on thier layout information... do same on other loop. now back tyo the boiler with two new pipes these are now your "Returns" the old returns go to supply side so now you have 4 supplys and 2 returns wih zones on them.... now bust out your magic circuit setter:) Hurray you the man of the day:)

Mark Eatherton1

I've used this method no less than 4 times...

and it has been succcesful every time. You may have to adjust the run times depending on the AUST in the area you're trying to heat.

Does anyone remember the article that showed up in P&M magazine, the one where the guy was doing staple up with 1,000 foot lengths? If my memory serves me correctly, he was driving that with 007's to boot... Boy, some peoples kids...

I had a homeowner DIYer one time that did the 1,000 foot lengths in a concrete slab. He was PO'd that "there were no instructions on the box!!"

Some peoples kids...

ME

m dewolfe

tubing

I once drained a long run in a greenhouse and threaded a stiff piece of mig welding wire into the tubing until I reached the 400 foot mark.Then by using a tone wand I found the halfway point and viola broke out my hammerdrill and the rest was history!

Kyle Kubs - Benchmark Home Inspections

Figures...

I was thinking along the same lines as weezbo... Can you get underneath anywhere? - These kind of guy's just burn my but. You can just see them standing there at the begining of it all, telling the customer, "Sure, we can do that..." and then people want to argue about price because they got two other quotes from idiots like these... Just to add to the fun stories... I inspected a 10 year old 6500sf house for a client a few months ago. Down in the boiler room was a nice big Weil. 298 000 BTU boiler with 8 zones. Problem? 2000 sf unfinished basement. behind the boiler are two 3/4' copper, yes copper..., tubes coming up through the concrete, going straight up to the primary manifolds. Tapped right of a typical zone. 1 Circuit. no secondary loop. no injection pump/ mixing valve... 180* water that a taco 007 was trying to push through who knows how long of a circuit.

Mark Woll_2

The welding wire thing is the most brilliant solution I've ever

heard! Too bad half of this install is gypsum concrete thin slap, over a recycled prior addition concrete slab. The other half is over a crawlspace.

Mark Woll_2

copper? that must be a typo, 2000sf?

Ken_8

Bet ya 20-bucks,

the system was designed by that guy in VT or the local supply house!

Could you find out please?

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Mad Dog

I like that...Sewer hogs

we have a saltier version in New York....sewer _____ (lady of the night, rhymes with sewer). Anyway, that is a very touchy situation. I now have a rule in those cases: I will go over the system with the homeowner ONLY. I'll write a report. It avoids fistfights, the police and lawsuits. Good luck with that job. I think Hot Rod's experiement gives you a fighting chance. Keep us posted. Mad Dog

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Mad Dog

I know its great just to get the heat working, but

do they ever complain about pump velocity noise or humming? You know how some people are: Yoiu fix a nearly unfixable problem and the they find some small thing to pick at. Mad Dog

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Mad Dog

Yeah but I bet their price was \"competitive\"

mad Dog

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Mad Dog

Damned straight

That was a great idea. Mad Dog

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Dale Pickard

Very Cool

Sounds like a great technique.

What exactly is a tone wand? Woundn't a metal detector find all the steel in the slab?

Dale

Dale Pickard

I don't doubt..

your experience. But are you sure you want to recommend it to pro's as a fix?

It's a good question, what the professional response should be to such a situation.

Clearly the high head pump is the first solution, but I think can be taken too far...like two 26-99 in series. Might as well just heat the building with electricity. :-)
I guess if the low output produces sufficient heat and the big dt's don't damage the boiler, (good app for a condensing boiler), then using the reversing valve as a fix seems appropriate. It's simple and cheap enough to try.

But, I hate to go through all the rube-like mechanical of flow reversal. I don't like to leave my name on stuff like that. I'm more inclined to go with the concrete saws and hammer drills and do it right. After all, we would always be repairing some one else's work, right? Let the owners and the original installers work with the problem while we work on the solution.

Why take the responsibility with a funky mechanical solution that can't really incease the output and (my spin) is likely to create more problems? From a business standpoint, we like to be careful before we adopt other peoples problem systems. It's nice to see a clear path to complete rehabilitation.

Dale

hr

Has anybody tried to tone PAP? It has been on my list of things

> Sounds like a great technique.

>

> What exactly is

> a tone wand? Woundn't a metal detector find all

> the steel in the slab?

>

> Dale





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hr

Has anybody tried to tone PAP?

It has been on my list of things to try.
I'd like to borrow a good tone generator before I buy!

Sure would be handy for the shops that want to start bolting things down after they have occupied for awhile. Pictures and measurements are not accurate enough. IR cameras are too expensive

Seems the tone should pinpoint it to the fraction of an inch??

hot rod


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Mad Dog

I agree with you too, Dale

I think it depends on the customer and what their expectations are. I have found that - in most case _ you are better off doing it over from scratch or walking away. Once you touch it, it is YOUR problem. With the right customer and if we are getting paid properly I would try it. Mad Dog

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Kyle Kubs - Benchmark Home Inspections

No, not a typo. It was copper. At least the portion that I could see going down through the slab. I couldn't believe it myself. Kept thinking, it must be something else, looking around... But that was it. I get the feeling the GC/Builder had somebody throw the copper down just before pouring the slab, long before any heating contractor got involved. But then again the way it was run into the boiler doesn't say much for whoever put the boiler in. Not that it would have mattered... The owners only used the basement for storage and probably never new it didn't work... Also never new they raised four kids in a house that had skyhigh Radon... NJ has no shortage of hack builders...

Kal Row

ever hear of a grundfos 26-99..

sure - it's 315 retail - but it's got 30ft of head

or a few 007's inline will do it too, i would leave 12 pipe diameters between them for quietness

hey, you were looking for a simple solution

Mark Eatherton1

The final decision...

is NEVER ours Dale. All I can do is give them the options and let THEM make the final decision as to whether or not they want to go through the "de-construction and re-construction" of their finished homes.

100% of those people (4 so far) given the option, have opted for the reversal mechanism.

Besides, I "own it" regardless of what THEY decide to do...We have so many "orphaned" systems I feel like Daddy Warbucks!

You're right though, if it were my decision, we'd be breaking out the saws and hammers, but not in a multi million dollar home where the installing contractor is no longer available for comment:-( Life sucks, then you have to come up with a fix.

ME

hr

Selling a demo or

repour in a lived in, furnished home is a pretty tough go:)

The long dong, long gone original installer is probably not going to be picking up the tab, I suspect

Although on my last fix he sprung for the cost of the pump upgrades and materials when threatened with a lawsuit, by the owner.

And like ME, I don't pretend or present it as a perfect fix, but I have yet to have an owner refuse to try one.

Cheaper and more comfortable than electric baseboard

The flow reverser, for the cost, is a big improvement over just feeding one end and a 44° delta t at the other end.

Not perfect, but sell-able

hot rod

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Kal Row

after heatloss & resistance screwups...flow problems is #2..

you'd think by now, people would have caught a clue, i am too honest about the cost and expectations up front - so i am lousy at selling the radiant jobs againt no-nothings, but i get called in afterward when all hell breaks loose - at that point the customer is already unhappy - i feel like a dentist - sure the customer will pay anything to get it fixed - but will hate you all the same

m dewolfe

Tone wands are often used to find buried cables and to find faults in overhead cables as well. If you havee ever seen the guys from call before you dig mark a gas or waterline with a strange set of headphones and a small box thats what they use.I have a dynatel unit that is about $3500 or so and works like a champ.I also have several small handheld units that also work quite well. I have tried to tone pex-al-pex thru the al and found that it works but only fairly and that was with the burnham pex brand others might act diferently.

scottO

1/2 pex tubing

There must be some really dumb people with a lot of money to burn. Anyone who has done one little bit of research on 1/2 inch tubing would now that the lenghts should only run 300 feet.

Dale Pickard

Providing a fix

Mark you said "Life sucks, then you have to come up with a fix."

Made me chuckle. It's what attracts me to what I do. I like being on the "fixing" end of things. One btu at at time. You and I are brothers in this regard.

I don't think that we agree about the problems of multi million dollar homes though. The way I see it, those folks pay for the correct solution. In this case the correct solution is the one that is most convienent and successful. I never want to meet their lawyers or their expert witnesses, but if I do, I want to find myself with the most technically defensible design. I don't see a lot of point in trying to save their money when they are foolish and cheap enough to find themselves in this situation to begin with.

I'd be more inclined to offer the reversing mix valve solution to some DIY'ers that got into trouble and need to do whatever they can. Though it's still true that the best fix is to dig up the concrete. I don't know that it's as difficult as we may think. Some folks "do" concrete and concrete repairs. I'd look to work with them.

Dale

S Davis

Fix

Have you considered locating the tubing and then going down into the crawl space and open up the floor from down there, if you can find the half way point of the loops you can just split them, I have done this twice on two big jobs one had a decorative finished concrete that would have beed impossible to match the other had 10 inch wide plank floors, its not fun but it can be done, you just set your skill saw a 1/4" less than the thickness of the floor make your cuts and then use a chisle, if you use a infared thermomoter you can pinpoint the tube pretty close and then just take it slow, you will not even have to mess with their flooring, and you will be the hero.

S Davis


Apex Radiant Heating

Unknown

009 taco

look at the 009 taco also

Andrew Hagen (ALH)

Time for baseboards

Why bother to sell them on anything? If they didn't want to repair the radiant slab right, then I think any repair I might suggest would involve abandoning the slab or installing a 2nd stage of heat to carry the building when the slab couldn't.

I just don't see this flow reversal as a fix. I think that we need to be clear. Switching the flow back and forth is not going to increase the flowrate or the output. All it can do is make the floor temperature more uniform. Nothing magic here. This is immutable. If you can't increase the flow, you can't increase the heat delivery and it really doesn't matter where you put the heat you can deliver if it's not enough.

If the output is insufficient, then such a "fix" is just setting them up to call the fixer on the cold day that the fix doesn't work. We are all usually pretty busy on those days anyway, usually with problems that can be fixed.
When I see a boondoggle like this going down, it's pretty hard to drop what I'm doing and jump in with the group and indulge in a lot of wishful thinking. Seems like the most professional thing to do is to tell it like it is. I really don't want to own their problem, just their solution.

Dale

Mark Woll_2

I went over the need for likely baseboards with the owner

mostly in the mudroom and laundry room areas which have the greatest heatloss. And are ice cold.

They are not inclined to dig up the slab. This is on concrete "sub-slab". Oh and get this... The contractor had ALREADY pulled up the whole wood foor once before because it cupped and warped about 4 weeks ago (inadequate curing/drying time for the slab? Maybe they didn't let the flooring acclimate?). Had I been there at that time, we could have fixed it.

So now the owners are on their 2nd Floor!

How about a third?