20 Sep 2000 at 12:08 pm #273544Anonymous
I am in the process of coverting my Cast Iron radiators to baseboard heaters, Question – Should I convert them all at the same time or can I convert them one floor at a time and still use the cast iron side with the new copper pipes connected as well. I am a running a loop system with an oil Boiler. Also does anyone know where I can get a book to help with the installation ?
20 Sep 2000 at 5:30 pm #287985
I advise replacing the system entirely at one time. The controls required to make the copper loop and the castiron section operate confortably at the same time add some expense and the possibility that this mix will remain for a long time is a terrible thought.
It is possible to install cast iron radiation on the copper loop and this would make the piecemeal transition easier. the cast iron baseboard will make a very comfortable home due to its long cycle of giving off heat.
But again it is better to do a complete, well-thought out design at one time. Concepts an installer needs to know are at http://www.hydronic.net
I am curious about your decision to change from the radiators to baseboard. European preferences are for wall radiators or floor radiant heat. Replacing the pipes in a working system is possible; they worked for 50 years. Is it an aesthetic choice? – No standing radiators, modernization, etc?
21 Sep 2000 at 2:52 am #287986
Yes, it is definately a choice based on aesthetics and modern updates, there is an unusual amount of cast Iron piping throughout the home and they are placed in very obstrusive locations out in the open, will I be losing any functionality by making this change or sacrificing comfort ?
I’ll plan to take your advise and make the change to the whole system at one time, should I start the Copper piping right from the source all the way to the end or will it be OK to start from one of the cast iron fittings outside the circulator ?
Thanks for you help….Rodney
[Edited by Rodney on 21 September 2000]
21 Sep 2000 at 4:51 am #287987
The decision to change from the original is a matter of preference. I would really be proud to show others the original cast iron; but then I would be happy to live in an original water-powered machine shop and go to work by bicycle.
Continuing the new pipe from a section of the cast iron in the basement should cause no problem. Take note of the location of the circulator and piping arrangements in the drawings at the web site. This is a good time to arrange the piping properly.
22 Sep 2000 at 6:04 am #287988
Thanks Harold, I’m sure it will work out I’ll let you the progress………Rodney
[Edited by Rodney on 22 September 2000]
22 Sep 2000 at 11:34 pm #287989
I normally agree with my good friend Harold but there is a lot more involved then just replacing pipe and fittings.
The most common failure seen in circulating
systems is erosion/corrosion. Erosion/corrosion is a mechanically induced
failure which may be caused by any or all of the following conditions:
1. Water at high velocity. High water velocity may be caused by an
undersized piping system or an oversized pump. One of the interesting myths
here is the notion that a return line failed because Type M copper was used,
so the repair is to install Type L copper. Since Type L copper has a smaller
ID than Type M copper, the velocity in the system is actually increased,
raising both the likelihood and rate of erosion that may take place. The
real solution is to lower the water velocity. Installation of a smaller
capacity pump or a throttling bypass on the existing pump should help in
lowering the velocity of the water in the system. The relationship is as
follows: Reduce pipe size, increase velocity; increase pipe size, reduce
velocity. Recommended velocity for hot water in a copper tube system is 4 –
5 feet per second (fps). If systems are designed to respect these velocities
the return lines will last as long as the rest of the system. The practice
of reducing tube diameter for the return line run is counter-productive and
is the main cause of high velocity in these systems. Since there is no
sizing guide in the Model Codes for return lines, there is little guidance
for the plumber on how to size this portion of the system. In the course of
installing or replacing circulating lines, some contractors have been
increasing the size of the return loop piping to 1″ or at least the same
diameter as the hot water supply out of the water heater.
2. Numerous, abrupt changes in direction in the piping system. Where
structural conditions cause numerous directional changes, long radius (1.5
Diameter) fittings should be used to minimize the interruption of laminar
flow. Pump manufacturers also have recommendations that limit the number of
changes in direction near the pump and the minimum distances these can be
installed from the pump. This is to protect the pump from these same
erosion/corrosion processes (cavitation). This is the main reason why you
would not use a corrugated connector on these pump installations. Flow
characteristics, the number and severity of the bends that could be made in
these connectors may be detrimental to the pump.
3. Lack of reaming the tube ends. Burrs left on the ID of the tube can
cause interruption of laminar flow resulting in localized high water
velocity and cavitation.
4. Protrusions into the flow stream caused by excessive lumps of
solder/brazing material, improperly fabricated tees (branch protruding into
the run pipe), etc. These protrusions can also cause the
interruption of laminar flow resulting in localized high water velocity and
5. Excessive water temperature. Heating water above 140 degrees Fahrenheit
can accelerate the process of erosion/corrosion. As the temperature
increases, the velocity should be lowered. At 180 degrees Fahrenheit, the
velocity should be down around 2 – 3 feet per second (fps).
Bear in mind that these conditions are not peculiar to copper tube, but can
affect other materials as well. However, when erosion/corrosion does occur
in copper tube it is readily identifiable by the horseshoe shaped pitting
throughout the inside of the tubes. Identification OD these pits or grooved
corrosion-product-free areas on the inside of the tube can help you
determine that water velocity is too high and that the reduction of velocity
can correct the condition.
I would strongly suggest you vist Harolds web site of contact your local Licensed Master plumber to properly design these systems.
[Edited by Moderator on 26 September 2000]
23 Sep 2000 at 12:09 am #287990
Good points, Sylvan. A Licensed Master Plumber is most likely to understand the problems of laminar flow and pay attention to the details necessary to prevent it in the piping to reduce noise and replacement of pipes and fittings.
The tables used to design small tube systems pay attention to the velocity of water in the pipes. As you say, velocities of water below 2 fps are useful in extending the life of the piping system. Velocities over 5 fps cause noise and accelerated erosion. Circuits that are too long create uneven heat and inadequate velocities.
Velocities in copper tube radiation effect the output of heat from the fin tube. Cast iron baseboard is a larger, unrestricted vessel, where velocities can not be too high and low velocities do not affect output.
Proper design of a system does not have to be a hit-or-miss situation. There is plenty of design information that has been given to a Licensed Master Plumber beside the experience.
23 Sep 2000 at 1:44 am #287991
Harold, the reason I like a slower velocity (Hazen-Williams) It does prevent eroding and other adverse conditions BUT as we know slowing the heated medium too much could cause another problem associated with a wide spread “DELTA” from supply and return water (thermo shock)
The ideal Delta I feel should be no more then 20 degrees But thats my opinion
Plumbers may know how to size the piping for domestic/potable water supply hot and cold But I find most journeymen are lacking in heating piping design and applications.
I also find that few “plumbers” get involved in fire suppression systems as the “K” factors and single sized piping arrangement systems tend to bore them as the sprinkler piping today is like putting a tinker toy set together with everything marked.
Plumbers are a natural for installing the smaller fire suppression systems in one family homes but they seem never to follow up on this built in gold mine.
I think the biggest turn off today for most legitimate plumbing contractors is the heating field is all the non licensed folks dabbling in under slab systems and the unknowing going to home centers for advice.
Dan H, wrote an article about going to a home center many years ago where this clerk said “one boiler fits all in residential applications”
When mentioning a Hoffman 75 with an Apollo ball valve below it for servicing the home center mentality kicks in asking CAN IT BE DONE CHEAPER never asking is this the right job?
I still install Cast Iron base board heating and Burham cast Iron radiators and NEVER have I ever installed a loop system always a two pipe system on hydronics
Very few apprentices learn EDR for steam (1 Sq. Ft will put out 240 BTUH when there is a 70 deg. Ambient around the radiator and 215 deg. (less then 1 psig) inside the radiator. Or 1 Sq. ft of EDR will put out 150 Btuh with an average temperature of 170 deg.
Ask any apprentice to go from EDR to BHP? Or EDR to Grate area in Sq. ft or EDR to BTUH steam at 1 psig.
Today they figure fixture units or developed length BUT have no clue that the figures they are using are no longer applicable.
The shame is ANYONE can and does advertise “heating” with no skills required.
At least if the plumber has a license you know he/she is insured.
Harold as always your a real pleaseure to talk with. please keep the education going as Lord knows the apprentices need your training as they cant seem to learn it on their own any more as the dead men cant tell them why!!! LOL
23 Sep 2000 at 2:42 am #287992
Yes Sylvan, it is unfortunate that ther is no licensing for heating and cooling as a profession in residential work in all states. As this profession began after the established professions of plumber, stationary engineer and electrician, the heating and air conditioning profession crosses these same trade areas. A fully licensed HVAC professional would need to be licensed in plumbing, stationary engineering, refrigeration, and electrician with minors in sheetmetal worker, carpenter, and mason. As there would be only one lifetime to get these licenses, the field has been permitted to be unlicensed.
This leaves sincere professionals, dabblers, handymen, and charlatans in the same customer service arena. The concept of the uneducated installing the most expensive and complex type of residential heating – slab radiant heating – with home center parts is ridiculous.
The hydronic heating manufacturers designed and accepted the series-loop heating circuit to make a hydronic system competitive with properly-installed warm air systems. That you can provide your customers with the more controllable 2-pipe cast-iron radiation system shows the willingness of customers to purchase a quality comfort system. A floor radiant system is a 2-pipe system by the nature of the many loops.
During the entire 40-year history of the education effort of the hydronic manufacturers, There were no more than 2000 plumbers who atttended the course that simplified the design of 2-pipe systems. This leaves a serious shortage of fully-qualified installers. I am happy to know that your customers have a fully qualified professional.
23 Sep 2000 at 3:03 am #287993
Thank you Harold .. By the way my “heaing guy” is a licensed “Stationary engineer” I just took in as a full partner to handle all heating.
I hope it works out.
27 Sep 2000 at 3:42 am #287994
Thank Goodness that after years of getting ripped off by Uncle Sam as well as So Called Licensed Contractors that are better at trying to intimidate Homeowners with a lot of Bull, Then doing what is needed.
We now have the right to try it ourselves, if we screw it up, we can then call someone we are comfortable with to help out.
And as the saying goes ‘ This is my House ‘.
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