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Hot water heating systems

While we are waiting for a plumber to respond, this is a must for everyone in that trade.......



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After all it takes longer to freeze cold water. Learnt that fast one winter in North Dakota. Will be waiting on your answer also. From what I have read no runs over 300 ft. and back to the manifold. What you using for a heat exchanger?
 
MO, like a lot of older houses in my neighborhood they had gravity feed coal fired hot water systems. Most were updated to either gas or oil. These gravity feed systems had no circulator and a 2inch riser and return. Those feed those older upright cast iron radiators. There was only a single zone for a two floor home. I have a question concerning a hot water system using these older radiators,i am somewhat experienced in there operation but seeking advice from a professional who understands about these systems
 
Have you no circulator? What you described as having now is a slow costly heating system.
What is the question about your radiators?
 
The diverting or venturi tees are only used with a system with a pump
what do you wish to know
Bruce
 
I understand all of what you are saying as I've installed a few systems. When i had older type radiators in the house i eliminated the ones on the second floor and used a single loop system with copper baseboard. On the first floor i ripped out all the old piping and used a loop system with a venturi tee feeding each radiator. Now you have to use a venturi tee on radiators or they won't work correctly,you cannot single loop them and if the do get hot the radiators on the end of the loop will be colder
This is exactly what happened to my neighbor whom I'm trying to help out. She had some half assed plumber come in when she had her her boiler installed and he ripped out all the old piping as she was finishing her basement and singled looped the entire first floor. What happens now is a few rad's get hot but the ones on the end of the loop are only warm. The house is old with no insulation in the wall so some rooms are freezing. What i want to do is were each pipe enters a rad and then exits,i want to cut the lines and install a venturi Tee setup on some of the rad's that are not getting hot and see if that helps
Of course the right way would be to take down all the ceiling tiles and rip everything out and install a 1'' header with branch off at each radiator using a venturi tee at each rad. That is the way i originally did my house as told to me by a old time heating guy and it worked great. I just can't handle the whole job myself but was thinking maybe one rad which is a real problem,doing this would help. I have my doubts as i don't know the water temp by the time it reach's this rad. I was looking for opinions if any by guys who might be in the business. Thanks for the help,i appreciate it
 
I know the job is screwed up to start with, and not knowing much detail, here goes, so, any chance there is a shutoff (ball valve) above or below the circulator? Maybe the boiler is to small, water moving though to fast, not enough hot water heating surface? If you have a valve, close one valve halfway or a little more (never fully closed). This idea (I have used and it worked because the water was moving though the boiler to fast to get hot enough, the boiler was sized wrong for very bad weather), should slow the water flow, with the water coming out of the boiler being hotter and lasting longer. Yes, first served radiators will get hotter and maybe the water getting to the last radiator may be holding it's heat longer (because it is coming out of the boiler hotter). Or you cut a bypass pipe between the radiator's feed (enter) side and the return (exit) side and install your venturi tee, the correct way of the flow. Now you have just created a zig-zag main, (no real straight running main). And either way you have to drain the system and fight the dribble water to solder copper pipes and fittings, (I do not know what type of pipe you have) or cut and thread steel pipe. Some installers use the Viega PEX 3/4" oxygen barrier pipe with press tight rings and fitting's , (good up to 100 psi, at 180 degrees temperature). But you already know which way will work the best the first time and your done, even if it is difficult.
Just an after thought here, You say "you'll put the venturi in the radiator that is the problem". That just moves warm water into that last cold radiator. How about putting the venturi at the first few and hottest radiators, that way the hot water will split and go onto the next radiator in the line? That's all I have for now.
Dame halfa$$ plumber, probably was an out of work Dentist and looked on youtube at what to do.
 
The problems Dual are two fold. Because the home has large radiators which hold more water there is so much heat loss,read that as the tempature of the water goes down as the water pass's from rad to rad hence the last rad in the loop is cold or not as warm as the first. When a loop is used were the rad's are tee's off there is always hot water circulating and you don't have that great of heat loss
The other major issue as i see it is water taking the path of least resistance. If you look at the construction of a old time radiator its not for instance constructed as if it had a series of coils. The bottom inlet of the rad goes right threw it to the outlet.What happens is the bottom of the rad will get hot but not the top because there is no forced circulation of water. If you opened the vent and bleed the rad it would get hot as now your forcing water but after you closed it then it gets cold. A venuri tee eliminates this as it forces water through the rad. The guy who redid the system in question just looped everything. In one side out the other just like if they were installing a baseboard single loop system
I think now that if i installed a venturi tee on the rad in the room that is cold it might help a little but now I'm thinking it won't be the difference I'm looking for as the water temp is to low due to loss from the other rad's in front of it. Ive been told a cast iron old time rad like the ones I'm talking about work best with 160 degree water passing through them and that's what my system had the high temp set at. The water temp at the rad in question probably is much lower.
I don't think there is any simple answer except to start over and do it right and get a licensed guy who has the experience to do the job. Ive told these people that and now its there decision as to what to do. Thanks for your replies and interest. Write back if you want----------BTW the outfit that did the job was from a utility,they installed the new boiler as part of the package did this other work. The homeowner wanted those 2inch riser and returns out so they could finish the basement and put up ceiling tiles. It would have been so simple to run a 1inch header around the whole perimeter of the basement and tap off at each rad with venturi tee's. Case closed no issues but these guys had no knowledge of how a system works and just were good at replacing the unit. Thats what happens when we close vocational shops in HS. What I'm talking about is basic plumbing skills and anybody who does residential heating work should know it.
 
If I understand this all the rads are in series and you are have lost most of the heat before it gets to the last one
the best way as you said is to repipe but for now you can cover most of the first rads so you have more heat making to the end to even out the heat
If this is a condensing boiler you need to keep the return water below 130F or it goes from 90's to 80's for efficiency
 
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