Too much head

[taxidermist]

Ok now lets talk boiler LOL!

Well after northwoodsman was kind enough to do the math for me he found out there is no way I could ever use my eko 60 to its full btu rating, or any where close. My set up...

Eko 60
150' logstor underground two 1" pex lines

1000gal storage in basement

On boiler taco 013 pump

total equiv. lenght of pipe= 544.77

based on a 13.6 gpm with a 20 deg drop I have 77 feet of head


If I would have used 150' of underground with two 1 1\2 lines I would only have 15' based on a 20deg drop and 13.6 gpm

NWM has all the calculations for this setup he will post later.

Thanks again Brian for the help

Rob

 

[LeonMSPT]

Sorry about the added expense and frustration... but now you know, right? It's like a picture, or an orchestra piece... every element can be "perfect" by itself, but if it doesn't all fit together right... it's not great... might be "good", but not great.

Know of one case where the boiler owner got so frustrated and angry, the dealer took the thing back to try and save his own reputation in the small town where the guy lived. Too bad I'd already jumped... could've gotten a decent deal on the GW-100...

 

[brad068]

Taxi, This might be a situation that a pump on the return might help out alot. Check with tcaldwell he did something like that.

 

[LeonMSPT]

Problem is, you just can't shove more than a certain amount of heat through the 1 inch line. It just won't fit. You can't pump the water through the line fast enough, and if you did the water wouldn't have contact time enough with the heat source to absorb it, or give it up.

It's why your car has a thermostat in the radiator line, and it overheats when it's stuck open. Granted, it has some more to do with the viscosity and specific heat of radiator fluid versus water, but the theory remains. If it goes by too fast, it doesn't take the heat.

 

[brad068]

Problem is, you just can't shove more than a certain amount of heat through the 1 inch line. It just won't fit. You can't pump the water through the line fast enough, and if you did the water wouldn't have contact time enough with the heat source to absorb it, or give it up.

It's why your car has a thermostat in the radiator line, and it overheats when it's stuck open. Granted, it has some more to do with the viscosity and specific heat of radiator fluid versus water, but the theory remains. If it goes by too fast, it doesn't take the heat.

Well I guess I never seen a car or any liquid cooled engine for that matter over heat from a stuck OPEN t-stat because they will never reach operating temps with it stuck open THATS why liquid cooled engines have t-stats to preserve the heat in the engine until it can afford to give it up at a regulated amounts just like your guys 3 way mixing setup for controlled return temps to the boiler.

The DD's operate in the same exact principle as a liquid cooled engine

 

[LeonMSPT]

Must not get very hot where you live. I realize the concept is difficult to grasp, but I am not doing the research for you. If the fluid media is going at too high a velocity past the surface of the heat exchanger it will not absorb the heat. Heat absorption and retention is related to volume, specific heat, velocity, and delta T.

Typical presentation of a thermostat stuck open in a vehicle is your ass is freezing in the winter, except when you're parked at a red light.
Summer time, (>95 degrees) is the darned thing blows its cookies at red lights and stop signs and cools off when you're going down the road.

Same problem, different situation.

Believe it or not. It matters not in the least. It's a matter of the laws of physics and thermodynamics.

Thermostatically controlled valves on storage allow the boiler to heat the house, then the storage... they also reduce thermal shock to the boiler from introducing water that is way too cold back into it.

 

[brad068]

Must not get very hot where you live. I realize the concept is difficult to grasp, but I am not doing the research for you. If the fluid media is going at too high a velocity past the surface of the heat exchanger it will not absorb the heat. Heat absorption and retention is related to volume, specific heat, velocity, and delta T.

Typical presentation of a thermostat stuck open in a vehicle is your ass is freezing in the winter, except when you're parked at a red light.
Summer time, (>95 degrees) is the darned thing blows its cookies at red lights and stop signs and cools off when you're going down the road.

Same problem, different situation.

Believe it or not. It matters not in the least. It's a matter of the laws of physics and thermodynamics.

Thermostatically controlled valves on storage allow the boiler to heat the house, then the storage... they also reduce thermal shock to the boiler from introducing water that is way too cold back into it.

Blowing the pressure off of the radiator has nothing to do with excessive velocity at which the fluid passes through the radiator. If it blows off in the hot summer while idling it is due to not circulating fast enough and the path of least resistance which in some cases is the open radiator loop. Idling the water pump is not moving fluid fast enough and will take the path of least resistence. Thats why when you accelerate the engine cools off dramatically.

And if the cooling fan is electric and not working that will cause problems to at long idle.

 

[Northwoodsman]

Taxidermist,

It was my pleasure helping you out with the calculations (believe it or not, I actually enjoy doing the math !)

However, I wanted to clarify one of the figures you posted:

13.6 GPM @ 77 ft. of head is not actually correct for your EKO60.

The correct number is actually 20 GPM due to your boiler being an EKO60 which is rated at 206,000 BTU/HR and not an EKO40 as I originally thought and calculated for.

206,000 / (500 x 20) =20.6 GPM

Also, below are the assumtions and calculations that I used in determining this pump sizing:

PUMP CALCULATION FOR EKO60 SYSTEM
01.17.09

QTY ITEM DESCRIPTION

348’ 1” Pex 348'
38’ 1” Black Pipe 38'
13’ 1-1/2” Black Pipe 13'
8 1-1/2” BP elbows x 4.03 32.24
6 1-1/2” BP tees x 2.68 16.08
6 1-1/2” ball valves x 6.50 39
2 1” Shark Bite elbows x 2.62 5.24
8 1” BP elbows x 2.62 20.96
7 1” BP tees x 1.75 12.25
2 1” Ball Valves x 1.80 3.6
1 1-1/2” Danfoss loading valve 16.4

TOTAL (Equiv. length pipe) 544.77

HL= k x c x L x (f1.75) where:

k=0.00223 (1” Pex) x 348’ = .776
k=0.00036 (1.5” Pex) x 348’ =.12528
k=0.0001(2” Pex) x 348’= =.0348
(notice this # drops significantly due to the larger diameter Pex, 1” dia. = .785 in2 area,
1.5” Pex =1.76 in2 area, 2” Pex =3.14 in2 area- more than double !)
k=0.000845 (1” copper/black pipe?) x 38’ = .032
k=0.000146 (1.5” copper/black pipe?) x 13’ = .002
c=.933 (water @ 180 degree)
L = 545 (equiv. length of piping circuit)
f1.75=101.327 (based on 13.6/14 GPM desired flow rate)
f1.75=189.148 (based on 20.6/20 GPM desired flow rate)


USING 348’ OF 1” PEX
HL=(.776+.032+.002) x .933 x 189.327 = 143 feet (based on 20 degree temp drop & 20.6 GPM design flow rate)

Because of the extra long length of 1” Pex the head is very high and thus not even a Taco 013 can provide 20.6 GPM at 143’ of head (a 014 is rated for a max of 8 GPM at 6’ of head). Even at a flow rate of less than 1 the Taco 014 has a max head of 35’.

When doing the initial calculation of target flow rate (Page 1 of Taco TD10 bulletin):
F = Q/(500 x∆t) where:
F= flow rate
Q=rate of heat transfer (BTU/Hr)
∆T=temperature drop of circuit (supply temp – return temp)

F=206,000 BTU/HR/ (500 x 20) = 20.6 GPM ( the EKO 40 is rated at 206,000BTU/HR)

When looking at table 1 on page 2 of the same bulletin, it shows that a 1” Pex has a minimum flow rate of 3.8 GPM and a max flow rate of 7.5 GPM. Thus, the 1” Pex is not large enough for this application. The proper size Pex would be 2.0” which has a min flow rate of 13.4 GPM and max. flow rate of 26.8 GPM.


Running the same calculation but using 1.5” Pex vs. 1” Pex results in the following:

USING 348’ OF 1.5” PEX
HL=(.12528+.032+.002) x .933 x 189.148 = 28 feet (based on 20 degree temp drop & 20.6 GPM design flow rate)

STILL QUITE A BIT OF HEAD ! (a Taco 013 is max. rated at 20 GPM @ 18 ft. of head, possibly a 014 might get the job done)

Running the same calculation but using 2.0” Pex vs. 1” Pex results in the following:

USING 348’ OF 2.0” PEX
HL=(.0348+.032+.002) x .933 x 189.148 = 12 feet (based on 20 degree temp drop & 20.6 GPM design flow rate)

THIS IS MORE LIKE IT ! This scenario can be taken care of with a Taco 011 pump which is rated at 20 GPM @ 13 ft. of head (a 013 would probably be best).

I have used the data listed for copper fittings/pipe when calculating the k value of the black pipe items. I’m assuming these are pretty close to the same but will investigate this further to verify.

The bottom line is something we've all heard before:

PAY ME NOW (FOR THE LARGER PEX) OR PAY ME LATER (FOR THE ELECTRICITY OF THE SUPER LARGE PUMP THAT IS REQUIRED WITH THE SMALLER PEX AND ALSO HAVING AN IN-EFFICIENT SYSTEM FOREVER!)

Warning to all - keep the Pex large when running it in long lengths !

Sorry to post all the details but I figured this might clarify things.

Can someone please check out my calcuations and let me know how they look?

NWM

 

[LeonMSPT]

Okay.

I'll try and explain a little more.

SNIPPED

Blowing the pressure off of the radiator has nothing to do with excessive velocity at which the fluid passes through the radiator. If it blows off in the hot summer while idling it is due to not circulating fast enough and the path of least resistance which in some cases is the open radiator loop. Idling the water pump is not moving fluid fast enough and will take the path of least resistence. Thats why when you accelerate the engine cools off dramatically.

***

If the above is true, then it should apply whether or not the thermostat is working or broken. Yes?

How come all those cars, parked in all those lines, up and down expressways in places I wouldn't live if they gave me the deed to the whole darned place, don't all overheat? I'll tell you why. When the thermostat is restricting the flow of radiator fluid in the system, the fluid remains moving at a lower velocity, allowing it to absorb the heat from the engine, and give it up as it goes through the radiator. Obviously, if the fan doesn't work the thing is going to overheat when it is sitting still and nothing is going to change that. Drive down the road and it cools itself. That is minimally related to a discussion about fluid velocity, mass, specific heat, and absorption/release.

The reason I know this is it happened to me. I didn't believe it either. I figured the thing was stuck closed... mechanic said, "No. If it was stuck closed it would overheat within five minutes of starting no matter what you were doing. If it's stuck open, it'll overheat idling at an intersection." The mechanic took almost an hour explaining it to me, because like you, I said, "Are you freaking serious? The thermostat is stuck open, and the thing overheats? How the hell does that happen?"

When you sit still at an intersection, there is no air moving across the radiator to cool the water, or it is not moving across the radiator as much as at speed.

Back to the original issue anyway. The plain fact is, a 1 inch pipe aint going to cut it when you're trying to move 100K BTU, or more, over any distance at all. Period.

There is no pump, valve, assist device, or doodad that is going to make more heat go into a 1 inch pipe. It's just a matter of the laws of physics and they don't make exceptions for good intentions or ignorance. Make a miscalculation on this and your system is worse than useless, and it's going to cost alot of money, aggravation, and frustration, before it's straightened out. How to fix it? Dig it all up, replace the piping with a larger pipe.

Take "just" 90/100K BTU's and move then 100 feet away from the destination, and then try to shove it through a 1 inch pipe, it just aint going to work. You might "get by", but the boiler is never going to be able to work the way it is capable of.

I own a 90K BTU conventional wood and coal boiler. In the manual it says in plain, black and white, english, "minimum pipe size for connection between boilers and bypass is 1 and 1/4 inches...." If 1 inch is "plenty", why do they require 1 and 1/4?

 

[LeonMSPT]

And what NWM said... great job. I am going to save that puppy to my hard drive. Summarizes the issue very well for anybody who can't wrap their heads around the issue.

 

[Northwoodsman]

LeonMSPT,

Thanks for the overheating explanation !

That scenario is exactly why/how I started my posting last month on tha fact that a circ. pump can be too much/large for a boiler (even though all the postings I had seen previously stated that's it better to have a little bigger pump.)

I have an EKO40 system (with 1,000 gallons of pressuized storage) with approx. 30' of 1-1/4" copper for the primary piping.

I had been burning it approx. 1.5 months (Nov/Dec 2008) before I realized (and then perfromed the calculations) that my pump was moving the water way too fast though my boiler and thus it was not removing the heat away from the boiler in an efficient manner.

I had a Taco 010 3 speed pump which I had been operating on HIGH (using approx. 125 watts of power).

After I did the calculations I found out that I had a system which only had 4' of head (due the large cooper tubing I used in the primary loop).

Thus, I immeditely changed the circ. pump to LOW speed (which operates the Taco 010 just like a 007 and uses approx. 75 watts of power) and my heat transfer into the tanks went from 52K BTU/HR to 103K BTU/HR.

I was able to prove the old saying that "you can't get something for nothing" is not true.

Actually, I was able to get 2X the BTU's for 50 watts less power

Hope this helps !

NWM

 

[LeonMSPT]

Here's an article that explains some of the issue...

From:

http://www.ehow.com/about_4597044_engine-thermostats-overheating.html

Time Frame
An engine can overheat rapidly or slowly, depending on the problem. If a thermostat is stuck shut, the antifreeze will not flow, which means it's stuck in the engine and does not have a chance to return to the radiator for cooling. The engine will overheat rapidly, usually within 15 minutes or less. If the thermostat is stuck open, the water flows too fast, which can also cause overheating. Generally, because the water does pass through the radiator, cooling does happen, so it takes longer for the vehicle to overheat.

****
Argument is how we learn. Without it, we would still be living in caves and rubbing sticks together to make fire. Someone said, "Hey... if we lived in houses with boilers, we'd be warmer...." now look at us. It's not a bad thing to argue. It's crazy to argue from the point of view that nothing can exist if we haven't seen it. It would take an extremely widely traveled and educated individual in order to reach such a point in life.

I've jumped several times over the years, thinking "my situation" was universal and global, only to find that a set of circumstances different from my own exist out there. And within those circumstances exists different situations from my own.

 

[LeonMSPT]

I know about enough to keep myself out of trouble on a daily basis, and maybe be of some use to someone else once in awhile. My high recommendation is this.

Before spending tens of thousands of dollars on a heating system, see a heating engineer and tell him what you want. He will draw the thing for you, and tell you how to set it up. Do it that way, and it will work the best for your dollar. Do it another way, and it may work, might even work "good". But the tweaks an engineer will build in will extract that much more heat for your money.

It's like going to an accountant to have your taxes done... if you don't have that much money in the first place, then it's probably not worth the money and trouble. Once you have enough money to wonder about it, the accountant's fees will pay for themselves in additional deductions and accuracy in your tax figures.

 

[leaddog]

If the boiler is not idleing and is full out burning then you are getting as many btu's as you can get. If you don't move it from the boiler it will idle. The only time my eko80 will idle is when I have my tanks almost fully charged and my return temp is 175* to 180*. I'm running double 1in pex 100ft into my tanks and most of the time my modulating valve is cycleing to keep my boiler temp up to 185* and if the return temp is 150* it will only open 1/2 way returning the rest to the boiler. Even with the output temp at 185 and return I have about 10% being returned to the boiler because off the way I have it set and thatis why it idles. This is with a full out burn with stack temp of 400*. I have a larger pump and was thinking about going to a 007 to help my modulating valve not have to work so hard with as wide of temp swings. My modulating 3 way valve is a honeywell 1-1/2 with a modutrol motor and using a honeywell temp controler pid
with what you are saying it looks like I'm not putting out more that a eko40 and I know that isn't true.
leaddog

 

[LeonMSPT]

Lot's of variables... "working" is not always "working as well as it possibly can". What you've got works, that's good because the alternative is dig it up and spend more money. My vote goes to designing the system BEFORE you build it, and find someplace else to cut corners besides pipe size. You won't "know" how it's going to work for sure until you use it. That's an awful poor time to find you've cut corners and forced yourself into one.

The numbers don't lie, but there are variables. The pipe can be too big too... it's important for things to be sized as "right" as they can be. There is no perfect, and a wide spectrum of things that will work between "doesn't work" and "works great, as good as possible". Because it's doing what it was installed to do doesn't mean it couldn't be more efficient, or work better. If it was done on guesswork and it works, it was a good and lucky guess.

When I am spending thousands of dollars, I'll be darned if a refrigerator salesman is going to sell me the refrigerator, and then tell me how I should build the house it's going in and how to wire it. The building contractor and electrician are there for that. Unless the people selling them are doing the installations regularly, and are licensed and experienced, I'll take it to the heating engineer or research deeply and do it right the first time.

Not optimal doesn't mean it won't work. Lots of stuff out here is not optimal and it works fine, gets the job done. Sometimes it doesn't though, and then no amount of excuses and additional pumps are going to make it work.

 

[brad068]

Alright, I'll try to explain this in a little more detail. I am a mechanic and that article was written by a woman columnist who probably heard that advice from the same mechanic you talked to. My first question is why would coolant from the engine want to flow through the radiator when it gets hot and the t-stat opens? Is it because it is just hotter and want to get out? is it scared? NO, It is a path of less restriction same principle with a zone valve. You use a zone valve in a differential pressure situation same with a thermostat. Most zone valves open on a remote t-stat and a car works solely on the internal control. A automotive thermostat is a zone valve and thermometer in one. The pressure differential is there now it just needs a switch to control it; thermostat. Its harder for the water pump to circulate the coolant through the engine block than it is to circulate it through the radiator. And I don't know if you know this but when your car is warming up the coolant is circulating throughout the engine block and heads to equally displace the heat to get the entire engine up to operating temp and then when that happens the t stat opens to expel the excess heat that is and will be generated during entire operation which is a place of less restriction but regulated by the thermostat.

Same theory/principle as the DD's and to avoid boiler shock.

Yes it will overheat idling with it stuck open but not from moving coolant to fast through the engine it just moving more through the radiator and water pump and not so much through the engine thats why it overheats and it has to expel pressure and the only designed place is through the cap. The technical term is short circuiting.

 

[LeonMSPT]

Hang on a minute...

***Well I guess I never seen a car or any liquid cooled engine for that matter over heat from a stuck OPEN t-stat because they will never reach operating temps with it stuck open THATS why liquid cooled engines have t-stats to preserve the heat in the engine until it can afford to give it up at a regulated amounts just like your guys 3 way mixing setup for controlled return temps to the boiler.

The DD’s operate in the same exact principle as a liquid cooled engine***

Not a mechanic, and don't play one on television. But you said earlier there is no way an internal combustion engine can overheat because a thermostat is stuck open, because you never seen it. Whether the fluid likes it better in the radiator loop or the engine loop, without restriction, free flow... the car overheats when the thermostat is stuck open, or missing because some idiot took it out because it was stuck closed and they forgot to put one back in when the got to where they could do it.

I've torn down and rebuilt two small block 350's. One of them, I sent off and had it machined, and when I put it back together it was a 383 making almost 400 horsepower at the rear wheels. Parts, materials, and machine work alone cost more than a crate motor would have... a 300 horsepower crate motor anyway. I have a vague idea about how to keep them cool... and why they might overheat.

Fluid moving too fast cannot absorb the heat from the surface it's flowing over. How about using a lighter oil than necessary in an engine? You're a mechanic. What happens when you put 5w-20 into an engine that requires 20w-50? The bearings overheat because the lighter oil is flying past them and not taking the heat away... the oil pressure drops off, and after a fashion they overheat, expand, and stick to the crankshaft, leave the keepers, and spin. Right?

Thermostat restricts flow through the radiator, closed it doesn't allow any. Fully open, it's like it doesn't exist. Most often, unless it's a cold start the thing will be somewhere between closed and open most of the time the car is operating and shortly after. Even closed, a smart installer will drill and small hole in it before he puts it in anyway... keep it from air locking, and most of them already have the hole anyway.

It's good we're both learning. I've learned another possible explanation for why a motor can overheat without a functioning thermostat. You've remembered that it can, in fact, actually happen. Wierd... we were both wrong... Typical...

Back to the original issue... straw men are so distracting...

Wide field out there of what "will work". Everything from "won't work at all" to "works the best it possibly could". You as a mechanic know that well, I am sure. You also know that it's better to design things from the ground up, instead of just wading in and building something without a plan that is designed to work and not just look pretty.

If you build something based on a guess, and don't want to rebuild it entirely to make it work when it doesn't, then if adding another pump will make it go, it's probably a better option than digging the entire thing up and redoing the piping in a larger size. That doesn't make it "right", it just makes it "work". It cannot work as well as a well designed and built system... anymore than taking a stuck thermostat out and buying bottled water to put in the radiator fixes the car.

Alright, I'll try to explain this in a little more detail. I am a mechanic and that article was written by a woman columnist who probably heard that advice from the same mechanic you talked to. My first question is why would coolant from the engine want to flow through the radiator when it gets hot and the t-stat opens? Is it because it is just hotter and want to get out? is it scared? NO, It is a path of less restriction same principle with a zone valve. You use a zone valve in a differential pressure situation same with a thermostat. Most zone valves open on a remote t-stat and a car works solely on the internal control. A automotive thermostat is a zone valve and thermometer in one. The pressure differential is there now it just needs a switch to control it; thermostat. Its harder for the water pump to circulate the coolant through the engine block than it is to circulate it through the radiator. And I don't know if you know this but when your car is warming up the coolant is circulating throughout the engine block and heads to equally displace the heat to get the entire engine up to operating temp and then when that happens the t stat opens to expel the excess heat that is and will be generated during entire operation which is a place of less restriction but regulated by the thermostat.

Same theory/principle as the DD's and to avoid boiler shock.

Yes it will overheat idling with it stuck open but not from moving coolant to fast through the engine it just moving more through the radiator and water pump and not so much through the engine thats why it overheats and it has to expel pressure and the only designed place is through the cap. The technical term is short circuiting.

 

[LeonMSPT]

Thanks for taking the time today. Not kidding either. This stuff makes me happy, and I am not being a wise guy. I learn loads from this kind of stuff, and if we don't have anybody we can bang heads with, we'll be ignorant all our lives.



So, the loop that moves more freely will be a happy home for the water, and the other loop will tend to overheat...

Connected in parallel, a wood boiler and a heating system could be thought of as a car engine and a radiator, obliquely... with the oil boiler as the "water pump"... I think we just found why people run into trouble with this sort of thing, and the "fix" when it happens is another pump to overcome the resistance in the wood boiler loop.

Never would have connected the dots today without this conversation.

Groundbreaking.

Thanks,
Leon

 

[brad068]

You got me on that. In all reality I haven't seen a car overheat because of a stuck open t-stat because the owner will come to me before that happens and ask how come my car isn't warming up like it use too? It seems to be using more fuel? My temp needle seems to move alot.

As for the oil the higher viscosity is for the high performance engines where more heat will be generated like your boat anchor 350's %-P ( can you tell I was raised around the blue ovals), but I think alot of that has to do with machined tolerances per hp and torque output. High rpms with extreme heat and load demands create a need for higher viscosity's.

Whats worse is put that higher viscosity oil in a engine that recommends 5w-20 and see how long the main and rod bearings last.
Every time you start you start the engine you'll think that theres a squirrel under the car with a machine gun

My uncle built a 427 stroker out of a 351 windsor that they put into a early 80's mustang. You talk about torque!

 

[heaterman]

Ok now lets talk boiler LOL!

Well after northwoodsman was kind enough to do the math for me he found out there is no way I could ever use my eko 60 to its full btu rating, or any where close. My set up...

Eko 60
150' logstor underground two 1" pex lines

1000gal storage in basement

On boiler taco 013 pump

total equiv. lenght of pipe= 544.77

based on a 13.6 gpm with a 20 deg drop I have 77 feet of head


If I would have used 150' of underground with two 1 1 lines I would only have 15' based on a 20deg drop and 13.6 gpm

NWM has all the calculations for this setup he will post later.

Thanks again Brian for the help

Rob

That's probably the most common mistake I see on installations using any type of remotely located boiler. The OWB hacks have settled on 1" pex as the maximum size needed for any and all applications and have done a masterful job of perpetuating that myth. I've have stood face to face with that type of installer and heard them say "If you need more heat just use a bigger pump". At which point I am left nearly speechless at the utter stupidity of that statement. It's hard to explain things like head and how many GPM are required to effectively carry XX,xxx BTU's to someone with absolutely no knowledge of hydronic piping or any inclination to learn.

So here's the rough rule of thumb again.

3/4 " tube = 4GPM = 40,000BTU
1" tube = 8GPM = 80,000 BTU
1.25" tube = 14 GPM = 140,000 BTU
1.5" tube = 22 GPM = 220,000 BTU

Once you try to go much above those flow rates in a given size tube you will find that about all you are doing is wasting electricity generating head instead of flow

NOTE: these are rough rules of thumb and flow rates will decrease drastically when tubing lengths exceed 150-200 ft.

 

[LeonMSPT]

Didn't start the thread, but would like to thank everybody. Great information and should be trumpeted far and wide for consideration BEFORE buying equipment and materials and piping anything up.

Rule of P's....

Proper Planning Prevents Piss Poor Performance

 

[henfruit]

heaterman did you forget me?

 

[heaterman]

heaterman did you forget me?

No my good man, I just haven't had a spare hour in the last two weeks to sit down, draw your piping out as I understand it, and think through your problem. Between when you posted and right now I had a guy show up at the door with a busted furnace blower and now I just got a call from someone with a CO alarm going off. It's been just a tad frantic around here lately. I cruise through and skim over a topic or two, make a post that doesn't require much time for thought and that's about all I can do right now. This is the time of year I have to make my living. I'd love nothing better than to be able to do just that by helping people on this forum who have problems but so far I haven't found a way. I'll have to see ya later.

 

[ken999]

Not that I can add alot to this thread but...

Two things.

1. A friend from work built his own OWB, modeled it after a Johnson. Wound up with a 3 speed (I think) pump (Grundofs). Had to run it on the low setting to get any heat out of his system. He had some other issue too...cavitation IIRC...anyways, slower was better.


2. I've been told by some people in the biz that there "cut-off" for advising 1" line at my lenght (80') is 140,000 BTU. Lucky for me, I have been listening to some of you and will be getting 1 1/4". I've got 96' of baseboard currently and a 33k Modine in the basement. I've been told that is around 80-90 k and I would like to run some radiant in the garage should I get around to fixing it up.


Nice thread fellas. Lot's for the inexperienced like myself to chew on.

 

[brad068]

LeonMSPT,

Thanks for the overheating explanation !

That scenario is exactly why/how I started my posting last month on tha fact that a circ. pump can be too much/large for a boiler (even though all the postings I had seen previously stated that's it better to have a little bigger pump.)

I have an EKO40 system (with 1,000 gallons of pressuized storage) with approx. 30' of 1-1/4" copper for the primary piping.

I had been burning it approx. 1.5 months (Nov/Dec 2008) before I realized (and then perfromed the calculations) that my pump was moving the water way too fast though my boiler and thus it was not removing the heat away from the boiler in an efficient manner.

I had a Taco 010 3 speed pump which I had been operating on HIGH (using approx. 125 watts of power).

After I did the calculations I found out that I had a system which only had 4' of head (due the large cooper tubing I used in the primary loop).

Thus, I immeditely changed the circ. pump to LOW speed (which operates the Taco 010 just like a 007 and uses approx. 75 watts of power) and my heat transfer into the tanks went from 52K BTU/HR to 103K BTU/HR.

I was able to prove the old saying that "you can't get something for nothing" is not true.

Actually, I was able to get 2X the BTU's for 50 watts less power

Hope this helps !

NWM

NWM, I agree with your figures and the bigger piping is a definite plus in these boiler setups. One thing that I am having a problem with in this post is that your circulator is moving water to fast through your boiler to extract heat from the boiler right? I got a few question to ask. 1. when you were charging/ heating on high speed, what was the burn like- was it cycling or burning full out? 2. do you have a temp gauges on the supply and return into the mixing valve or boiler and if yes what was the temp span between high and low flow?


I guess what I'm picturing is that its not a problem of moving water to fast through the boiler but a case of hot water cumming back to soon from storage maybe a short cycling problem in the plumbing

I know, correct me cause I am probably wrong. I burn a garn style so I don't do the burn/pump/charge.