Hydronic Hell

Alaskan · November 2013

Hello All, Came across your website while researching for the umpteenth time a solution to my heating problem. Hoping you might have some insight into our heating problem that no one else has been able to resolve including my plumber. I’m also posting this in one other forum.

 

I live on the in Alaska in a 75’ by 30’ Quonset hut style metal building that sits on a slab. It was built in 1993 and the original owner who built it has admittedly said he would greatly change what he did if he did it now. He installed two 1000’ loops of ½” polybutylene qest tubing that are heated by a Bock 32E oil fired Hot water heater(since replaced with a new one) and has a single Grundfos UPS 20-42f pump pushing water through both lines. As it is an open system, the Bock also fills all our hot water needs in the living area. The building is broken up into a 25’ living area on the south end and 50’ garage/shop area on the north side. From what the original homeowner remembers, one of the 1000’s loops goes side to side in the 25’ living area and the other 1000’ loop goes lengthwise front to back in the garage area.

 

During cold spells below zero the heating system is lucky to maintain 50 degrees by itself. The only way we have been able to make it through the cold winters is to augment the heating system with a coal/wood burning stove. Several years ago, I purchased a Royall indoor wood/coal boiler but have never installed it due to my research on how the qest tubing would cause the cast iron boiler to eventually fail and running a heat exchanger with this inefficient system doesn’t seem to make it an option.

 

I wonder if adding a pump pulling water through would help or even upgrading to a bigger pump, but have limited understanding on how head pressure would affect these ideas. Lately, my thought is to install two zone valves after the pump so that I can concentrate more hot water to the living area as it becomes much colder since the stove is in the garage.

 

So from my limited understanding, my issues are: 

 

1. Hydronic tubing runs are at least double of what they should be.

2. Polybutylene qest tubing allows oxygen into the water which will cause a cast iron boiler to breakdown more rapidly which will also create its own issue of iron particles in the system. Fortunately I haven’t had any other issues with the qest tubing.

3. The Bock hot water heater is probably overwhelmed to do the job even if all other factors were okay.

4. An open system, which may or may not be an issue depending upon how it is used?

5. Cement slab prohibits making any changes to tubing. I’m 6’ 5” and the ceiling in our living area is 7’ so running new tubing and then capping won’t work either.

 

I’m sure there are other issues, but these seem to be the main ones. 

 

I appreciate any suggestions or input you may have that will help me.

Gordy · November 2013

1000' loops

And an open system with non o2 barrier tubing.

Yeah it's a mess. 1/2" tubing should be 300' loops need to break the two 1000' loops up into 4 loops each 1000' loop. Not impossible.

There has been use of a reversing valve that switches flow direction every few minutes but 1000' is a bit much.

Honestly I would abandon and go over the top with a new tubing ( o2 barrier pex) layout. Was slab insulated?

Losing an 1" of head room if slab was previously insulated would be better than trying to make what you have work.

Zman · November 2013

Punt!

I think you have a pretty good grasp of your situation.

The tubing lengths are the real killer. You are 5x the ideal lengths and 3 times workable. Even with larger circs the temp drop through a loop that long will create hot and cold spots. A circ that large will by costly to purchase and operate.

You did not mention slab insulation.

The other issues are solvable on there own, you cannot transfer the heat needed with 1000 foot runs.

If this was my system, I would start looking at alternative heat.

Panel radiators of forced air?

Carl

Gordy · November 2013

Do you know

Your heat loss?

What water temps you are using now?

What the difference in temps between supply and return of the loops are?

Tube lay out must be about 1' centers.

Mark Eatherton · November 2013

Phour way reversing Phun....

Been there, seen that, applied this and made the space feel better, but short of jack hammer surgery to break the tube circuits into smaller lengths, all the best you can hope for with a 4 way reversing valve is to chase the cold out of the middle.

If you can, you should consider possibly adding radiant walls to the living space to make your comfort "automatic".

If you do employ the 4 way reverser, you will need a 4 way valve and motor (ESBE)m a timer (WW Grainger) and anti condensing valve (ESBE).

The pumps will probably end up being like 2 Grundfos UP 2699's in series just to push 1 GPM (a SWAG on my part and needs to be engineered to be sure. There may even be a single pump capable of pushing the head you need to overcome the pressure drop in those 1,000 ' circuits.

Question from last person who pulled this 1,000 foot loop trick "Why don't they put some instructions on the box?!?" My response, "No one would read them anyway, and there's not enough room to explain every method of application"...

Good luck with your system...

ME

Weezbo · November 2013

Jack Hammer.

find like 250 ' in on one loop and 250 in on another find where these come up at , convert over from pB to same size pex .

once you have the "Locates ,

it is the best way , thin out the general ambiguity and make new decisions .

a guy asked me how to make it work once , like Mark , i used the washing machine trick ,

bumped it up to 58 in the place ... here is what you have to contend with , heat loss.

here is what you have going for you ...thermal mass.

it wont freeze till your heat loss drinks the stored BTU's from the slab.

so , i would not be half stepping when the cold snap breaks .

there is more to it than simply locating the end of the pipe . i would re load the slab before undertaking any real fix or you will likely lose the whole thing .

Or if you dig deep enough you can spend your way to success.

............

The next drop will be 20 degrees colder yet or more , and we are quite a ways from Late Dec early Feb.. where i can and definitely has gone even deeper into the cold .

right now its just like late Autumn lol..

why last night in this neck of the woods it was a balmy 35 to 40 below.

....................

your home might look a bit different as you lash up the new quick fixes to get heat rolling again buh at Least you will then have progressively more heat going and better and better control over it ,

at first the guy was reluctant , no wanna do that so because i am only like 50 something at the time he called some one else who after banging his head against the wall told him he knew of a guy who does this type of work and who he had work on his own home to help out lol and the guy said bring him over ..

so we show up over there ....lol...

yah , theres way more to it than doing right , know what to do when is the trick when its cold.

*~//:)

or like i say you might be able to spend yourself to success.

bill_105 · November 2013

Imagine that

The length of 3 football feilds of tubing with an i.d. the size of a pencil. Also its an open system.Yikes!

Just curios Alaskan, just where in AK is this? I feel real bad for you.

Weezbo · November 2013

there is 365,000,000 acres here

choose one : )))

the place is lousey with land , dark and cold at this time of the year.

Mark and i are saying the same thing , the guy said ,

" i should have done this the first time "... i agreed with him and added ,

" It cost you double just to see me this time . and its cold out , and you may have to haul some of my tools around and pick me up at the house every day ... and enlist that brother in law of yours to turn a hand ."

" ; ))

Steamfitter66 · November 2013

Need more info

before we help you salvage what you can as economically as possible.

A picture is worth alot

Do you have supply and return temps?

Below slab insulation?

A few thoughts

1 your tubing cant give up all yhe heat the Bock can produce.

2 It takes 4X the energy to push 2x the water through the same size pipe

3 Start with a heat loss calculation.

4 you probably dont need a new boiler.

5 really need more info before we can give accurate advice.

Weezbo · November 2013

making the two loops ,4

new loops that function ,

will when it warms up ,which it is supposed to do tomorrow by finding the 250 foot marks

and attaching run outs to ends of everything that is found and the best way "Home " to the boiler will buy you more time and get more BTU's into the slab .

two of the ends become supplies two become returns . the other ends , you do supplies if they have returns connected back to the boiler from that point ,

the other end goes back as a return to header..

the places that connect the new lines are then best cosmetically part of the building hidden as a post , ( run up and to the lid and bac or into a partition , or run to nearest wall.

so , in that way once things have heat , you have something that looks planned ..

remote headers with 1 " run outs can reduce effort and multiple smaller pipes headed back to the Bock.

..... once you have the grip on the field side , then you want to get the temps down in the lines , and work on getting the potable on its own path ways .the existing cold is where i would make taps maybe . depending on what material the cold water lines were run in ,

rather than get too involved , i am going to say that when you have more heat in the building you may decide that some area still just doesn't have enough heat and you will have to make coherent choices that most closely match the heat loss in that area.

by then though you have more heat and a far more comfortable area in which to work out those details.

another thing is you may find that rolling a camper into the garage to live in "Works" if the temp drops down outside severely. remember Thermal Mass is what you have going for you ....

when you roll a camper in it is coming from the cold and provides an immediate place for heat to go "Heat loss again " yet it is and will become part of the thermal mass.

while the lines dont have to be 250 feet that will allow the area to be transformed the quickest way to the lowest water temp.

balancing is something of an art form ...

the day you roll the camper back out the door there went a chunk of BTU's ...

however the floor will respond slowly and that thermal mass will likely bring things back up in mins to temp..soon as the garage door is closed .

the reversing trick uses circs and things "Parts" that are spendy however the circs may not be ideally suited to any part of the system there after .

these are difficult choices to make ... that is why i am telling you this before buying into it .

Infil tration around the garage door is a Big Deal and you may need to think about the shop door closure door construction heights and r value ... if the quonset hut shop is 7 feet high then the camper idea wont help .

being able to do this quickly requires tools . otherwise ,.. it cost time as well looking for price an availability of them .

thats where , finding some help , having some tools , materials on hand and plenty coffee and auxiliary heat all come in handy when the help arrives ..

doing your homework in advance helps keep you out of problems of this nature in the future . because this is not the only trade where people take off doing things that they are way in over their heads with and "Sell" it to someone else to deal with.

hope that helps , i live just outside the town of North Pole . and have seen this on more than one occasion ,

there are people who can balance and blueprint an engine , folks who can rebuild old aeroplanes , and others who are great yellow iron knick knack operators each being highly skilled ,

you may not be able to find one who is available at any given moment is the point i am trying to convey . so look for someone who can cast an eye on the project before you embark on any changes ..

and by the way get it done yesterday ...

: )

hot_rod · November 2013

reversing

actually works quite well. I've built a few for long loops.

This one is a tekmar 4 way valve, find them online for around $130. Then use a 26-99, around $250. Belimo around 200 bucks. A simple lamp timer will reverse the valve ever 30 minutes or so.

After I built this mount and coupler I discovered Belimo sells the mounting bracket and coupler. So a 600 dollar investment, or less might be worth a try? A brass or stainless circ would be nice with and open system, but adds $

You could also series another Grundfos like you have to get addition head, instead of replacing with a high head circ.

Weezbo · November 2013

The thing with the valve and actuator is ,

it can be used in the balancing for lower temps should it not quite address the problem .

however , i will say it again , we do not have a heat loss number , and when the temps dive .... what works today in ten above is looking a little thin in 50 below ...and if you are in the "Flatts" rather than in the hills above the ice fog blanket at 12 foot or lower in 60 ,..70 ,..or near 80 below temps it is a very inappropriate time to discover that ...

Weezbo

*~//: )

hot_rod · November 2013

chances are

that the slab will not be your sole source of heat, ever. Based on what info we have so far. A reverser will make the best of a bad loop design and install, and even the slab temps better.

During cold conditions consider panel rads or radiant walls or ceilings to assist the slab.

Agreed the load calc is the key to getting it right the second time.

Gordy · November 2013

Hot rod

Do you have any timer starting point data per loop length? Something that gets close to a dial in point.

Realizing of course there are a whole host of variables with a red headed step child.

What's the longest loop you have salvaged?

Mark feel free to interject!

One other thing in this scenario. Would a reverser setup be better on each loop?

hot_rod · November 2013

The data I used

was from this article that Siggy wrote in 2004!

http://www.pmmag.com/articles/87331-the-long-way-around-br-john-siegenthaler-pe

The jobs I did were following some concrete guys around that always used a 1000 foot coil. The ones I did reverse claimed much better slab temperatures. The load wasn't the problem, just un-even slab temperatures.

The above mentioned job may not have enough slab area to heat the space regardless of reversing, but it would even out temps.

I think a 30 minute reverse is about right, but no data to support that

Bob Gagnon plumbing and heating · November 2013

Insulation Under Slab??

I'll bet if the job was installed that bad, they also insulated poorly, you may make all those corrections to your floor only to find out that most of your BTU's are migrating out to the surrounding ground. I would put radiant in the ceilings or walls and abandon the floor.

Thanks, Bob Gagnon

Weezbo · November 2013

Quonsit huts

this is a particular piece of work it looks lile a giant 25 ' D turned side ways and drug across the ground 75 '.

That might be the rough approximation of a big culvert chopped in half stuck on some pony walls maybe...with insulation spray foamed through out the entirety of the D with conveentional 2" foam rail roaded 2X6 foamed walls wired and sheetrocked on both "Gable ends" all on an insulated slab on grade monopour ..rebar and wire mesh abounds.

i have plumbed one about 46 ' high and a couple hundred feet long with mens and ladies , bars kitchen and three tank Brewery .

drain waste and vent being particularily challenging , yah...

these are much different buildings ....

some have boxes of rough cut married to them ,...which may seem frugal on first perusal buh when you consider heating them there is where the attention to detail pays off , ...

Hot Rod is King in my books

*~/

so, maybe some nice Swoopy copper home made rads to warm up personal space ... .. Alaskan , hot Rod has some examples of what can be done with a little creativity and an understanding of hydronics .

... maybe you can find some links here to Hot Rods personal art ...

even a nice headder piped primary secondary would 'Warm" up your home .

any way , It is as he says . ..

*~//:)

Hydronic Hell

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