Radiant Heating Issue 1954 House

Gronski Plumbing and Heating

Hi guys, hope someone can help me out on this, maybe an old timer, I have a customer with a house built in 1954, slab on grade with radiant heat. The house is 1200 square feet. The radiant tubing is all 1" black steel pipe in the floor.The system header is original with 1 1/4" header feeding six 1" black steel lines with 1" globe valves on each of the feed lines. The return header is original and it just comes back as an 1 1/4" header out of the floor.Here is the problem,an oil company changed the boiler in May. They installed a Weil McClain 3 section oil fired hot water boiler,net out put is 100,000 btu.They attached to the return side of the boiler from the bottem to the original return 1 1/4".The supply side of the boiler, they fed off the top of the boiler to the header in 1" copper to the 1 1/4" original steel header.The circulator is also a Taco 007. The weather here is starting to get cold,so the customer turned on the heat the other day and set the thermostat to 70 degrees, the boiler has not stopped running in over 2 days now. I can not even get the boiler to shut down on 150 on the high limit. I shot the supply with my laser thermometer and it was a 146 degrees, the return coming back was 99 degrees.thats a 45degree delta tee, The circulator is working, and I purged the system, and no air came out. I am reckoning that the system circulator is not enough to pump the required volume of water and to overcome the head loss of the system, plus the 1" supply from the boiler to the header probably has an effect on this performance as well.The company that installed the boiler sid there is nothing wrong with the system and it takes a while to heat the house,I say thats bull, over 2 days now? My questions are as follows:
1. How do I know what size circulator is required to make this system work if I have no idea how many feet of tubing is in the floor? (i am going to do a square foot analysis of the house with 1" tubing on my radiant heat calculations program just to see what comes up)
2. How do I balance the flow of each loop in the system to evenly distribute the flow of water with no temp gauges or flow meters to do so?
3.What is the correct delta tee for the supply and return temp on this type of system?
4. Is the boiler sized correctly for this type of application?( I think it is)
Thanks for the help comrads and make me look like a hero with this customer

jvw

making you a hero

Steve

I am on board call me.it will cost you a bottle or two of your famous wine.

the old man from Mass just North of you

Ted_9

007?

Hey Steve. I think your first suspicions are correct. It also sounds like the 007 is wrong. With 1" loops there is little resistance. So a pump that can move more gallons required(more gpm per min.)

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DanHolohan

Look

HERE in the Library, on page 2, where it speaks of large pipe.

It pays to wander off the Wall.

Mark Hunt

Near boiler piping


Is the boiler piped Primary/Secondary?

Any type of by-pass or boiler protection at all?

Mark H

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Gronski Plumbing and Heating

No the boiler is not piped primary/secondary, its return in supply out

Mark Hunt

OK


Are you saying that the radiant slab is getting sent 150 degree water? No tempering of the supply water to the slab?

The boiler is piped wrong. That is the problem.

Mark H

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Gronski Plumbing and Heating

Then how should it be piped?

Hey mark,
I definetly think something is wrong with how the boiler is tied into the system,but after reading what Dan sent me in the Original thread I started yesterday, I dont see any tempering at all on this type of system, I think it may be piped backwards,and the circulator is not enough, but I did not do the job, and the local oil company who changed the boiler, says there is nothing wrong, but i tend to disagree ........how do you think it should have been piped?The original sytem was installed in 1954, and I see no signs of a mixing valve or any kind of tempering on the old system that the new boiler was installed to.According to what I got from Dan, the syetem should work on the 140 water temp max going out to the system.

Ted_9

Steve

You'll need to protect the boiler using primary/secondary piping.

John can make a diagram for you. Ill see if I have one already.

This one gives you a basic idea.

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Ken_40

Answers:

1) You don't need to know what size you need. It doesn't matter. Anything around a B&G Series 100 or TACO 110 curve will do. Back then, those were the circulators that did 95% of all homes in that size-range. They were practically, the only pumps being made. To this day, they are still suitable for almost any residential setting. The 007 et al, are very similar in head/GPM - when near the center-third performance range; which is where all pumps "want" to run anyhow...

2) No gages required. Typically, the returns have plug cocks at the return ends. "Shoot" those fittings with you temp.-gun with them all open. See which one is coolest. Leave that one full open and then balance the remaining ones to the open one's temperature. By doing so, you will have successfully "balanced" the entire system!

3) Since you're stuck with what's there, there is no "correct" dT. Whatever it takes, it takes. I would suspect something around 10F as an acceptable dT.

4) The boiler is twice what's needed. But since the smallest W/M they make is the one installed, that's a non-issue as well. Down firing the nozzle to the lowest allowed rating, would be a nice touch.

Can we assume there is no tankless coil on this boiler and no other "use."

A bypass may be a nice touch. On those "first few days of slab heat up," the boiler water will languish below 140 for some time; condensing like a bandit. If it only happens a few times a year, no biggy. If it appears to happen a lot, you must install a bypass, if some form of bypass isn't already present.

And no. It is NOT a fluke that the boiler has run 48 hours to heat what amounts to many, many tons of 60 degree concrete, probably without any insulation between the slab and dirt below. Matter of fact, people in Beijing are seeing snow melt by the Great Wall (;-o)

And finally, it is perfectly okay to run the radiant system at well over 100F and is NOT wrong, nor detrimental to any part of the system. In my old, 1950 radiant slab home, we ran water temps at 180 and had to. We hated the rubberized asphalt floor tiles and put foam and wall to wall down and had no choice. All of Levittown, NY does and did exactly that! So once again: There is NO piping or design flaw. The notion of low water temps in radiant is a new mind-set, not appplicable to anything older than 15-20 years.

Z'at help?

Weezbo

*``/:) snowed again today ...

winter is comming , get it together ....

time for a new years resolution i will not double click or talk to myself

Weezbo

is there some chance that there are some valves.....

that are either "lost" or closed?

funny thing how 400 years experience could blow right by that idea..

there is a temp aquastat on your boiler readjust its top temp setting up to 190 close 5 of the six globe valves ,time the temp reading on the return in 30 second increments, for 3 mins then close it and move to the next one.... your mystery will probably reveal itself within the hour

Gronski Plumbing and Heating

I know the valves are all opened, the temperature gauges on the boilers on Weil McClain stink as far as trying to determine any accurate temperature reading while the boiler is running.Ive seen the temperature read on the gauge 150 when the limit is seton 180 and shuts off on 180.They are way to slow in response

Gronski Plumbing and Heating

Ted, from what I have been reading, those boilers in those days did not have any primary secondary, and It does not look like the existing system had it either......so it had to work before because it did till the boiler was changed

Ken_40

Answers:

1) You don't need to know what size you need. It doesn't matter. Anything around a B&G Series 100 or TACO 110 curve will do. Back then, those were the circulators that did 95% of all homes in that size-range. They were practically, the only pumps being made. To this day, they are still suitable for almost any residential setting. The 007 et al, are very similar in head/GPM - when near the center-third performance range; which is where all pumps "want" to run anyhow...

2) No gages required. Typically, the returns have plug cocks at the return ends. "Shoot" those fittings with you temp.-gun with them all open. See which one is coolest. Leave that one full open and then balance the remaining ones to the open one's temperature. By doing so, you will have successfully "balanced" the entire system!

3) Since you're stuck with what's there, there is no "correct" dT. Whatever it takes, it takes. I would suspect something around 10F as an acceptable dT.

4) The boiler is twice what's needed. But since the smallest W/M they make is the one installed, that's a non-issue as well. Down firing the nozzle to the lowest allowed rating, would be a nice touch.

Can we assume there is no tankless coil on this boiler and no other "use."

A bypass may be a nice touch. On those "first few days of slab heat up," the boiler water will languish below 140 for some time; condensing like a bandit. If it only happens a few times a year, no biggy. If it appears to happen a lot, you must install a bypass, if some form of bypass isn't already present.

And no. It is NOT a fluke that the boiler has run 48 hours to heat what amounts to many, many tons of 60 degree concrete, probably without any insulation between the slab and dirt below. Matter of fact, people in Beijing are seeing snow melt by the Great Wall (;-o)

And finally, it is perfectly okay to run the radiant system at well over 100F and is NOT wrong, nor detrimental to any part of the system. In my old, 1950 radiant slab home, we ran water temps at 180 and had to. We hated the rubberized asphalt floor tiles and put foam and wall to wall down and had no choice. All of Levittown, NY does and did exactly that! So once again: There is NO piping or design flaw. The notion of low water temps in radiant is a new mind-set, not appplicable to anything older than 15-20 years.

Z'at help?

Weezbo

i misunderstood...

i thought that you used your temp gun to read the return header in toto and what i suggested was to measure each loop one at a time. that could give you an indication as to what was going on and at the same time give you some idea as to what was going through what pipe...the other thought is ,as you were asked, are the rooms overheating?

you have a electronic laser gun right? if not this is a perfect reason to get one for future bugaboos such as this.... a thermostat with a spring on it for pipe is fairly old style independent verification means one of those takes a shade longer to come along to temp....

Weezbo

question is before What?

Ted is making a suggestion ... Paul is making a suggestion you dont have to belive anyone however these are ideas that we use everyday...


there is a chance that you will happen upon an idea that you may have overlooked in controling the heat ,the distribution system is There not alot you can do about it however, you can check the valves and a 4 way mixer will with an outdoor reset or a injection loop with an outdoor reset can make a distinct impression on the operation of the boiler and at the same time make a dent in the finacial comfort to the owner in the long haul..

Gronski Plumbing and Heating

I understand that everyone is making suggestions, and i know that in todays era of radiant, that is how it could be done and I have done systems like that, but I have yet to see anything from diagrams of radiant piping in the 40,s and 50,s showing this.....I was hoping that some old time guys are around who actually installed, or was anapprentice in those days of radiant, would be able to give me some input.
Steve

Ken_40

Steve,

What is it about what I wrote twice, that you don't understand?

Gronski Plumbing and Heating

Hey Ken,so if i am rerading this right, the Supply is the 1 1/4" pipe going into the floor, and the reurn is the 1 1/4" header feeding the 6 1" lines with the globe valves going into the floor, correct?

Ken_40

Yes!

!

[Deleted User]

Geezer Hydronics...

Never thought there would come a time I'd be calling myself an old timer. Guess it happens to everyone. I've decided that in my mind, I don't EVER want to grow up. Too bad my mind has ZERO control over my body's wishes.

To be perfectly honest with you, I've never actually installed one of these systems, but have talked to alot of old guys that have, and they were pioneers back in the day. If they'd have known then what we know now, they'd have done it differently.

THe fact that these old cast iron beauties have lasted as long as they did is a direct testimony to the casting technology of days gone by. "They don't make 'em like they used to", has LOT of meaning when applied to this technology.

THe new boiler that was instaled will NOT last as long as the old one because the castings are MUCH thinner. The old one condensed for certain periods of time too, there was just more material to lose before it became an issue.

The fact that there is no insulation below the slab has more to do with inital extended start up and run time than anything. Once the thermal mass flywheel is charged and up and running, it has the momentum of a 100 car coal train. Tough to get started, and it takes for ever to stop it once it is up and running. Her's is just getting started.

Applying todays technology might give the consumer more life expectancy from the boiler, but on inital first of the season start up, it is STILL going to run for numerous days on end before it shuts down. Tis the nature of the beast, and short of lifting the whole house up and applying insulation on top of the dirt, theres not a lot you can do about it, unless the HO wants to consider moving the radiant from the floor to the ceiling...which they may very well HAVE to do once the steel pies start failing, which they eventually will.

As for the math, using your IR thermometer, figure out what centers the tubing is on. Once you figure that out, take the square footage of the home and divide it by the number of loops (assuming equal loop length) and you will come up with an approximation of the loop lengths.

For example, if you determine the tubes are 18" O.C., then there is approximatley 2/3 of a foot of pipe per square foot of heated space. So in your case, 1200 square feet times .66 = 800 linear feet of pipe. Assuming that all circuit lengths are of equal distance, then 800 divided by 6 = 133 linear feet each.

Assuming the 35 btu's per square foot per hour maximum recommended delivery capacity, 35 times 1200 = 42,000 btuH. Assuming a 20 degree delta T, this would equate to 4.2 GPM. 4.2 GPM divided by 6 circuits equals .7 GPM per circuit. Using my B&G wheel of certain hydronic facts and figures, a 1 GPM flow rate (.7 rounded up) in 1" iron pipe produces 2 feet of head per 100 feet of pipe, so 2 X 1.3 (hundreds of feet of pipe) = 2.6 feet of head. So your minimum system needs are 6 GPM@ 3' of head. Remember, this is the minimum needs at design conditions.

The old guys who did these sytems bent the steel using bending mandrels, so you may need to factor something in there for the radi of the bends, or not.

Once that is done, assume a maximum delivery capacity of 35 btus/square foot per hour, times the square footage of the house. Assume a delta T of 20 degrees F once the house hits a point of stability. You now know your overal flow requirements in GPM. Using B&G SystemSizer software, calculate the pressure drop of the 1" B.I.P. circuit (throw a little something extra in there for rough internal piping surfaces) and you now know the feet of head required to size the main distribution circulator.

The easiest way to address the long term cold return condensation production issue is to throw an ESBE Thermic valve on the system. It will only allow whatever excess heat is available out into the system, all while keeping the return temp above the dew point of the flue gases.

If the HO has no budget, hire a professional IR videographer in to determine exactly where all the circuits go, and consider throwing zone valves onto the system so the HO can keep the bedrooms cooler than the living room. Use wireless thermostats to bring the whole thing together, and you will be a REAL hero, delivering system documentation, system protection and reduced energy bills. If there is a programmable set back thermostat, get rid of it. It will only cause problems due to slow reaction times of the mass intensive distribution system.

Attached, please find a Taco 007 and a B&G 100 curve transposed over the top of each other. If all of my assumptions are correct, your pump is plenty big.

I think that other than the possibility of having the new boiler exposed to long term condensation production, and not having any below slab insulation, the system is fine.

But thats just one old geezer input. Lets see what the other geezers have to say:-)

ME

Mark Hunt

It wasn't a boiler


they replaced. They replaced a water heater.

That boiler will be toast in no time.

Mark H

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J. WALTER BOOTH

1957 RADIANT FLOOR

We had the same configuration in our cottage built back in 1957. The only difference was our pipe was placed in a sand
bed before the floor was poured. That was a large heat sink
to heat up before the house felt warm.
This was back before glycol so the system was filled with
a hydrolic fluid to keep from freezing. It took two series 100s one on supply ,one on return to get the oil moving.
once up to temp one pump did the job.
On a cold start in january from stone cold, it took all of two days non-stop to get the building up to temp.
I would believe by the time you have read all of these responses your HO will have a comfortable home.
Just a note on the replacement system 1-1/2" gyprete,
1/2" pex, boiler a half the size,primary secondary piping
and two zones instead of one. Cold start via phone hook up,
cottage warm in six hours.
Techology its a wonderful thing.

Walt

David_39

Well, I'll contribute about my 1956 system, not sure if it will be helpful. 2500 sq. ft stone rambler - stone over concrete block with new highly insulated windows and doors. All I remember about my boiler is it is a 1990 Burnham replacement with "168 MBH". Three 1/8 HP circulators. Black iron 1 1/4 sends go out into the slab, 1" return pipes collect at a "bus" and go back to the boiler. Interestingly the boiler has it's own pipe loop w/a Taco "Air Scoop" and an expansion tank...the system connect off that loop with the high side the output and the low part (return to boiler) the circulators. Oil guy told me the circulators won't start until the boiler loop reaches 150F. I did each circuit one at a time, first one took 1.5 hours for the return water to even be warm feeling, other 2 went faster.

Yesterday it took 3-4 hours to get all slabs warm. House has a mix of carpet, vinyl tile, and laminate flooring. Temp in main part of house rose from 63F to 68F in about 2.5 hours, and actually overshot to 71F. As of 1am last night - I started around noon - it had not had to refire. Pretty amazing.

Best form of heat I've known and I hope it keeps working but I know the days are numbered. It feels like the inside of your house has been transported to Arizona. (well, not dry air, just warm w/o drafts)