Radiators coolish warm

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  #1  
Old 08-05-04, 08:08 PM
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Radiators coolish warm

Hello, I live in a bungalo with hot water heat. The rads furthest from the furnace are always coolish warm and the rooms are cold in the winter. There is no air in the system or these rads, there are shut off valves on both rads and they are in the open position. All other rads are hot. What could cause this? or how could I posibbly solve it.

Thanks again!!!
 
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Old 08-06-04, 05:59 PM
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It sounds like the flow needs to be balanced. The closest radiators are short-circuiting water back to the boiler and using up all the flow. Find the radiator that is closest to the boiler and close off the valve at least half way. Also close down on the one closest to the thermostat. This should make a difference and you may have to close them almost all the way to balance things out.

Ken
 
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Old 08-07-04, 09:01 PM
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ok after checking all the rads it seems that the three furthest from the boiler have shut off valves. The four closest do not. I am guessing next step is to install valves.

I think that the entire instalation is a mess around the boiler and much more complicated than my neighbours(3 houses are the same)

Thanks and I hope that I may ask more questions. This is a wonderful site.
 
  #4  
Old 08-15-04, 04:43 PM
Homer Simpson
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Coolish Warm an Oxymoron

Mark,

Balancing valves are a specially designed valve. It is not a globe, gate, or any
similar type shut off valve. To use one for balancing you would probably have
to close it 95% shut. To read more on balancing go to armstrongpumps.com
and read their PDF on the Technology of Balancing. You need special tools
to set the flow, called Differential pressure gauges. There are valve that have gauges built into them and all you have to do is use an allen wrench to
set the flow (FLOWGUARD by istec-corp.com).

Is sounds as if there is a flow problem (unbalanced system). When the shortest circuits shut closed does the the heat suddenly move to the longest circuits? But, if you only have one thermostat controlling the whole house, you couldn't shut down the shortest circuit because they are not zoned
seperately. Hopefully that is not the case with you, each zone (circuit) is controlled seperately?

Put the flowguards on the return line to the boiler.

Some circuit, the flow will be set to 1 gal/min others 2 1/2 , 3 , or 4 gal/min.
your pump has to be capable of delivering the flow in gal/min at a particular
resistance of the system (called pressure loss), measured in Feet of Head of water column. 1 psi=2.31 feet of head. The water flowing through a pipe
rubs on the walls of the pipe resulting in a pressure loss due to friction, also there is turbulance when the flow changes direction. The pump must overcome this friction and turbulance loss. But only size the pump for the circuit with the highest pressure loss, if it can overcome that circuit, it can overcome the others. This is more than you wanted to know.
Say goodbye, Homer. Goodbye
 
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Old 08-17-04, 08:53 PM
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Well actually I really like all the extra info it seems to make sense more often then not.

I can't shut the shortest circuits off to see since there is are no valves there. Seems only the 3 longest runs have them.
Thanks for the armstrong sight on balancing am still having a little trouble understanding that one.
And unfortunately I do only have one thermostat to run the whole system, no zoning etc.
As far as my pump is concerned I never even thought to look or see if it will handle the mods. Thought that when the boiler was installed in 1998 that the installers would have checked that. I know not a wise idea. but need to read up on how to check that to.... Guess it would be easier to hire someone but I can't afford that at the moment.
 
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Old 08-19-04, 10:23 AM
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The pump that I have on the boiler is an Armstrong Astro-30. Since I live in a bungalo I think that this may be ok form what I have read.

What do you think?

Cheers,

Mark
 
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Old 08-20-04, 12:59 PM
Homer Simpson
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Pumps and CBVs

Mark,

I am looking at the Armstrong Astro 30 performace curve. Using the middle
1/3 of the curve. You would pump from 6 to 10 gal per min at 7 to 12 feet of
head. Read some of the other threads on this site, I have explained it there.

I don't know the boiler that you are using so I don't know the pressure loss
thru the boiler that the pump must overcome along with the pressure loss of the piping to the radiator and back to the boiler that is added to the pressure
loss of the boiler since you only have one pump handling everything.

You may not have the necessary flow through the system in gal/Min as a
whole.

The more pressure loss (friction Loss) that you need to overcome the less
water flows throught the system in gal/min. Looking at the curve if you had
to overcome 17 feet of head, you would only have 2 gal/Min flow through the
system. Most of that flow would go through the shortest loops, hence,
the longest loops being coolish warm.

Circuit Balancing Valves help greatly in balancing out the flow through the loops. Use FlowGuard 3/4" 1/2 thru 4 gal/min flow. They are made by WWW.istec-corp.com. Model # 2907. You can adjust it with an allen wrench and see the flow on a built in gauge. My digital meter for doing this costs $2500. So it is better to buy the Flowguard for $75 each. One thing about installing CBVs. Pay attention to the direction of the flow through the valve (don't run the flow thru the valve backwards). Always have ten diameters of straight pipe on the input and at least 5 diameters of straight pipe on the output of the CBV. 3/4" X 10 = 7 1/2" imput length of straight pipe. etc. Of course it can be longer. You need a CBV for each loop. Install the CBVs on the loop return pipes at the boiler manifold. These valve work only if there is sufficient flow through the system to regulate. Which bring us back to the pump and the pressure loss of the system.

If the pump is the pump that the manufacturer install on the boiler, it is
probably sized for the pressure lose of the boiler. You may need to gang
the pump (put 2 pumps in series to increase the head) or replace the pump with one that has more capacity.

How do you determine the system head? Measure the longest Loop from the
boiler to the last radiator and back to the boiler. How long is the straight pipe
all added together? How many 90 deg, 45 deg fitting are there in that loop?
I assume everything is 3/4" copper pipe type M. With that information I can
add that to the manifold and boiler pressure loss to determine the pressure
loss that the pump need to overcome. Guessing that the flow should be about 3.5 gal/m per loop you have the flow of 12 to 14 gal/min which the
pump has to deliver at the pressure loss of the system. To determine the
precise flow a lot of thing need to be considered, Heat Load, Length of baseboard, length of the loop, water temperature, etc.

It is always good to have fully ported ball valves on the supply and the return
of each loop. If one loop fail in winter you can shut off that loop and still heat the house. With out valves you need to shut down the whole system
until repairs are made. Say goodbye, Homer. Goodbye

P.S. Ya, the Technology of Balancing is for engineers and balancing contractors. Real technical.
 
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Old 08-20-04, 07:35 PM
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It certainly is...I love it! Well this is what I found

Boiler is a Slant Fin "Galaxy"

Model: GG100HXPED
Gas altitude 480 feet
I/P BTU 100,000
O/P BTU 80,000


rising from boiler 36" to a tee and 90 elbow @1 1/2" pipe ,2 1/2" pipe 1 90 elbow @21' 6", downsize to 1 1/2" pipe @ 6', downsize pipe to 3/4" @43",
2 45 elbows, 5 90 elbows @ 13'

Rad 39W X 24H 4 ribs deep (cast iron)

All pipes are steel original from date of build 1948.

I have posted in which radiator to use but will close that one and only post here think my brain will like that better.

Now I was wondering why use copper mains, branch, etc over steel, which even when they installed my boiler in 1998 they still used steel. I do understand now that copper will have less resistance to flow over steel but having said that wouldn't copper become a larger heat sink do to its conductivity over steel. Would this result in more heat loss prior to getting to the rads???

Also the diameter distance for the CBV's of straight pipe. I do not have any room above at the rads to provide this much extra pipe distance. Is there a trick to getting this. or am I going to need to get these CBV's set below the floor then finish the ceiling?
 

Last edited by Exile; 08-20-04 at 07:55 PM.
  #9  
Old 08-23-04, 09:13 PM
Homer Simpson
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Slantfin boiler

Mark,

I have a Slantfin boiler in my house, which I am getting ready to replace with
a Munchkin boiler and Ultra stor indirect water heater. I put mine in in '83'.
From Slantfin's web site the boiler seems the same as mine. With the price or
NGas I need something more energy efficient.

The output pipe size of the boiler is 1 1/2" vertical from the top of the boiler.
The imput of the boiler goes into a pump. They use to put a Bell & Gossett
series 100 pump on the boiler which was a 1/3 hp pump. I changed to
a 1/8 hp wet rotor pump for energy economy reasons.

The way that you descrbe your system is that the output from the boiler
comes out of the top, makes one big loop to your cast iron registers one
at a time, with the supply to a register coming off the big pipe and the
return from the register going back into the big pipe. The big pipe returns
to the pump at the boiler. Have I got that right? Therefore, there is no room
for a Circuit Balancing valve because the 3/4" pipe to the register from the big pipe is too short. Reading your discription again, you're saying that your
maniflold loop is 75' long?

This must be old piping arrangement because the installer was tryng to regulate the flow and econimize by using decreasing sizes of pipes on the
supply. 1948 would make sense. If it was 1948, steel was used because of
custom and it was much cheaper and less labor intensive than
copper.

How does the water exit the register and return to the boiler pump?

Is the coolish warm registers an add on, installed later? Do the register come
off the big pipe?

I'm a little confused. Getback to me. Say goodbye, Homer. Goodbye.
 
  #10  
Old 08-24-04, 10:35 AM
Homer Simpson
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Post your e-mail address and you can send me a jpeg. HS
 
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Old 08-25-04, 06:43 PM
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Hello Homer, I sent you a private message
 
  #12  
Old 08-27-04, 01:51 PM
Homer Simpson
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Where is it?

[email protected]
 
  #13  
Old 08-28-04, 07:19 PM
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Hello Homer I have sent you the pictures
 
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Old 08-28-04, 07:34 PM
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In your last post you are correct the big pipe does go the lenth of the house pretty much except for the back part of the house where the run is 3/4". Yes from the big pipe as it goes down the house there is a tee to branch each cast iron register then back into the other big pipe and back to the boiler pump. This happens for the rest of the house. When This furnace was installed they prettymuch did the same style in the basement by adding 1" piping running the same path then down to each rad.

I am willing to get rid of all of this and run smaller piping.

Oh yes by the way I didn't notice any saving in fuel from my high efficancy oil burner and this new gas furnaceand still owe $4,000 on it from 1998 install cost was 5200. Yes I do feel cheated. When I asked the gas company for assistance because there was a problem they told me to call a plumber...even though they installed it.


Oh....yes the cool rads do come off the big pipe they are the end run. If you recall where the 2.5" goes to 1.5" then 3/" to the rads. Hope that makes it clearer.

Thanks again!
 
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