More powerful circulator?

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  #1  
Old 10-28-11, 12:56 PM
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More powerful circulator?

Would replacing the Grundfos #15-58 circulator make sense? I
have little or no circulation to my radiators now that I installed a 3-way thermic valve. I needed to protect the boiler. The valve is on the return. The circ. pulls down from there into the boiler. The boiler has a by-pass, but it needed something more to raise the operating temp. 20F to 30F. The boiler is now 140F but the circulation in the radiators is poor. Much worse than before I installed the valve. The farthest radiators do not get warm at all. The boiler heat remains in the pipes close to the boiler. The thermostat gets satisfied from heat from the other rooms. Makes no sense but it shuts the boiler, the boiler's cut off does not.
Now the system makes a sloshing sound as well. Not wanting to do a primary/secondary, I was thinking of replacing the Grundfos #15-58 with something more powerful, like a 26 series Grundfos. This time of year is not really cold, but the circulation system needs to flow a lot better than it is doing now.
What do you think?
 
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Old 10-28-11, 03:25 PM
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more powerful circulator

That noise in the boiler is air and air in a hydronic system will prevent heating bleed air from rads
 
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Old 10-28-11, 03:33 PM
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I have always stated that a thermic valve should have p/s secondary as it is a system bypass and will affect the system flow.
A standard boiler bypass would have sufficed. A boiler bypass is cold return to hot supply. Many people get confused with the boiler return temp thing. The return temp is not as important as boiler flow. If you can't get the return temp up then reduce the flow through so the boiler can get above the condensing temp. To quote Gil Carlson the inventor of the boiler bypass in the fifties. "Condensation and thermal stress is a result of extremely cold water entering the boiler or cool water at a high flow rate".
A system bypass will affect the flow in the system and a boiler bypass will maximize flow in the system which maximizes heat output.
See the link below.
Bypass_Piping_Explaination
 
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Old 10-28-11, 05:32 PM
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Definitely air in your pipes. You need to get that out. That is why your radiators are not getting hot.

Can explain in more detail the problem you were having? Why wasn't the bypass good enough? Was the supply temp too low?
 
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Old 10-29-11, 01:52 PM
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Thanks. I have removed about a half gallon of water from each of the 7 radiators and no air in any. I filled them thoroughly after piping the thermic valve. Before the thermic valve, I had just the by-pass (with a Globe valve there), and a GLobe valve on the supply. Yes, the spply temp was too low. I was unable to get the boiler to run long enough. The room thermostat would shut it off and on the coldest days the boiler would be 120-125F. That temp was when the supply was reduced with the globe valve close almost 2/3. The furthest radiators would barely warm. I have the same circulator then as now. It must be a flow problem. It was marginal before and worse now. The ESBE TV465A is very commonly used. It is said to not add much load. Could my expansion tank have broken down? My house is old, but tight and well insulated. I'm thinking that adding another circulator in a P/S arrangement may have to be done. I would prefer to change the circulator and rebalance. I think I need more flow. When the boiler was installed, it was sized to the radiation. It is about twice what I need to satisfy the computed heat loss. A lot of water acts like a heat sink. All that said, I want a comfortable apartment. I need a system which runs normally and one which would leave me only to set the raditor flow in each rrom to fine tune the comfort. With the thermic valve I have solved the boiler temperature but the flow is defintely worse whatever I do to tweek the globe valves. If air is in there, I can only keep bleeding and see if it shows up. Let me know.
 
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Old 10-29-11, 02:25 PM
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You should be adjusting the valve on the bypass, not the supply. Having it all the way open is usually the correct position for that valve. However, I don't think you need one to start with. You need to slow down with what you are doing because you are just throwing parts at your problem without understanding what your problem is and how to properly solve it. Were you the one that put the bypass in to start with?

You problem is short cycling because the boiler is twice the size it should be. A boiler bypass is not going to fix that problem. It will make it worse. You need to add a buffer tank. This link will be helpful to you: Buffer Tank FAQ

Do you have an indirect water heater? If you do, you may be able to use that as your buffer tank.

Also, what rbeck said is very important to understand.
 
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Old 10-29-11, 02:30 PM
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What is your boiler DOE output and your calculated heat loss?
 
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Old 10-29-11, 03:51 PM
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I did not install the by-pass. It was advised to protect the boiler, and I had it
installed with the gas boiler. It is a system bypass. The boiler is 80K DOE, a Burnham 204,with a pilot, chimney vented. It has no indirect water heater. My heat loss, using
the Unico web site, comes out to be 52.8K. Even that seems high. Radiation is 71K.
Three season's ago when the boiler was new, I had the problem right away. The
following year, I was advised to change it to a boiler by-pass, which I had a plumber
do. I may have been misunderstanding things, but the boiler by-pass changed nothing. Low boiler temperature persisted. The heat may have been more even. Next, I got a new consultation, and that resulted in changing things back to a system bypass, and
use the Grundfos #15-58 and set it on low speed. Last winter was like the one I began with. I persisted last spring. The ESBE approach was recommended. I plumbed it in.
This discussion is my persistence. So now I have, for the first time, a boiler running
above 120F. I at least got that far, after 3 winters and many variations. I don't want to believe it either. I want to take an easy way to get more flow. But if I must, I will get a plumber to add a primary/Secondary. I have the extra circulator standing by.
Installing only the ESBE was advised and as an alternative the primary/secondary set
up was also advised. After my attemps over 3 years, Installing a more powerful
circulator to improve flow. I don't know if that would work. That was my original question for all of you. If it flatly is not the way, and Primary/ secondary clearly is, then I will start making calls to get a plumber. All the close boiler piping is 1 1/4" iron and and
doing more piping, this late in the season, is not something I want to do. So, is the
consensus to do the Primary/Secondary?
 
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Old 10-29-11, 04:08 PM
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Let's slow down on your decision making. From your story, it seems like you have been getting some bad advice. This forum has some knowledgeable people on it and I think we can get you a solution figured out, but you need to have some patience. I'm not familiar with your pump, but I am sure it is more than adequate for your system. I believe a larger pump will make matters worse. Let's get some more information on your system.

What type of emitters do you have? Fin tube baseboard, cast iron radiator, something else?

What type heat exchanger is the 204? What does the manual say about boiler protection? does it recommend a boiler bypass or system bypass?

Have you run the boiler with the bypass closed? If so, do you get adequate heat?

What is the pressure in your system and at what temperature?
 
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Old 10-29-11, 04:24 PM
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Let's see some pictures of what was done. Host at photobucket or similar and provide links here. The 15-58 is PLENTY for this application. As rbeck said, the bypass needed here can be simpler.
 
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Old 10-29-11, 05:05 PM
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Heres the install manual gentlemen for your reference...... Shows a two circ piping with bypass.

Would seem logical to pipe exactly as the I/O manual states.


http://www.usboiler.net/products/boi...ets/manual.pdf


Has rads... One zone?????

I have removed about a half gallon of water from each of the 7 radiators

Cut and past from file above.

H. Use a boiler bypass if the boiler is to be



operated in a system which has a largevolume or excessive radiation where lowboiler water temperatures may beencountered (i.e. converted gravitycirculation system, etc.).Install a pipe tee at the boiler return alongwith a second tee in the supply piping asshown in Figure 3. The bypass should be the same



size as the supply and return lines with valves



located in the bypass and supply outlet as illustrated



in Figure 3 in order to regulate water flow to



maintain higher boiler water temperatures.



Set the boiler supply valve to fully open position,and the boiler bypass valve to half throttle. Operatethe boiler and adjust the bypass valve to achieve180F to 200F supply water temperature by closingthe bypass valve to decrease supply temperature oropening the bypass valve to increase watertemperature. If the bypass valve is fully opened andthe boiler water temperature is still below 180F,slowly begin closing the boiler supply valve toachieve 180F to 200F supply water temperature.




Never fully close the boiler supply valve



Mike NJ
 

Last edited by lawrosa; 10-29-11 at 05:38 PM.
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Old 10-30-11, 07:38 AM
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With flow in my system showing me it is more important, I agree with returning to the
boiler by-pass. I will plumb it back to that. The #15-58 gives me speed choices which
didn't have before. I will see what that can provide to raise the boiler temperature. I will now have two ESBE valves for sale. (I have two boilers, one for each of two apartments). Thanks, everyone for your help.
 
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Old 10-30-11, 07:56 AM
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I will now have two ESBE valves for sale
You should wait until others brief over the I/O manual I posted. The manual also shows a balancing valves, and I am not sure how that corolates. Then show one at the end of the loop in the diagram, with a ft note.

You see the two circs page #7 fig #3?

But again wait until the pros chime in.

And also take pics of the system if you want the best advice. The pros need to really see whats going on. "A pic tells a thousand words"!!

Mike NJ
 
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Old 10-30-11, 07:07 PM
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Burnham uses all boiler bypasses in their residential products except the LE/LEDV.
I believe you miss-adjusted your boiler bypass before. Leave the bypass valve wide open and slow the flow into the boiler with the supply valve which could actually be mounted on the return also. Remember slow the flow through the boiler, gets hotter faster. Your flow rate in the system will increase. If you reduce the flow rate into the boiler don't panic over the water temperature.
The idea is to get the flow into the boiler closer to the water volume in the boiler. A boiler with 80k DOE is between 4 and 8 gpm flow.
The delta T through the boiler is dependent on your radiation and amount of zones.
 
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Old 11-01-11, 07:42 AM
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I didn't see that balancing valve in that factory diagram before now. My system has never had it. I can send a photo if I knew how. Two years ago a boiler by-pass was set up and used, the piping was changed from the original system by-pass. That was clearly inadequate. I tried, but could not make the boiler bypass raise the boiler above 120/125. I was stunned because this was personally directed by Burnham. I could't tell them that.
However, this thermic valve raises the boiler temp. easily. Removing it and going back to a boiler bypass will improve the flow. Now, thinking back, I'm not sure I used it right, I didn't take notes. I made valve adjustments for sure.
This time; I did not use a Danfoss Balancing valve in the bypass and their literature calls for one. As I had a globe valve in the bypass, I thought that would be good enough. If I was more sure, that a Danfoss balancing valve in the bypass could solve my flow problem, I would get a Danfoss Balancing valve. It is much easier to plumb just the bypass. But it is hard to think that a Danfoss Balancing valve in the bypass could make such a difference in the flow supply to my radiators. I welcome feedback on this. (I may have worn out the Danfoss rep., I have no answer yet). My apartments are commonplace, my radiators as well, so this heating exercise has to have have a solution. Yes, my heat load is low, maybe lower than typical.
 
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Old 11-03-11, 08:00 PM
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Outdoor reset control

Would an outdoor reset and a 4 way mixing valve solve boiler protection issues and at the same time save up to 30% on oil.
 
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Old 11-28-11, 07:56 AM
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I replumbed and removed the thermic valve. I piped a boiler bypass as in the Burnham booklet. Is the circulator the right one? It ran hours to warm up the fresh street water and raise the room thermostat from 64F to 69F(?) I have 2" to 1 1/2" mains, (two supply, two return, 32 feet long each in a "T"). Circ. is a Grundfos #15-58 set at mid.
 
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Old 11-28-11, 10:06 AM
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Did you adjust the boiler bypass? If so what valve did you adjust? The bypass should be 100% wide open. You slow the water down in the boiler by adjusting the valve letting water into the return side of the boiler. If you reduce flow you can get the boiler to any temperature you want. My guess in the past you were adjusting the bypass valve. This would only make your situation worse. I usually say do not even put a valve in the full sized bypass. The bypass hopefully is 1-1/4" pipe.
You shouldn't need a bigger pump. That could make the situation worse. Remember the boiler can only handle a maximum flow of 8 gpm. Exceed that and your water will take longer to heat up.
 
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Old 11-28-11, 05:21 PM
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Raising room temperature several degrees takes a long time when the boiler water is 120 degrees. This is normal. If you want to raise room temperature faster, you need a hotter supply temp. Pump size is not going to help you there. When I started using water temps in the 120-130 range, I gave up my set backs.
 
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