Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 07-08-2009, 11:52 AM   #16
Member
 
tk03's Avatar
 
Join Date: Sep 2008
Location: PA
Posts: 167
Rewards Points: 150
Default

Boiler size


But using IBR instead of DOE and the fudge built into the heat loss programs of 15% to 20% you way oversize the appliance again. I have used DOE for about 20 years now and see many others on the Internet sites using DOE, and I have never had a problem. There is also some fudge in the IBR rating as it is a formula and not a true test. This uses some basic info which is not true to any specific application.
I have straightened out some jobs others have done, but it was not a boiler issue.
When I blame the piping I am blaming the near boiler piping. Would you not address that when the boiler is installed? Then the piping issues go away. That leaves flow issues. Again address that at the time of the boiler installation.

tk03 is offline   Reply With Quote
Old 07-08-2009, 12:06 PM   #17
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,942
Rewards Points: 3,554
Default

Boiler size


1950 era homes aren't set up with primary secondary piping.
So if their is a problem with it. Its the installer that created the problem.

If you have low flow in the pipes, doesn't matter if you use DOE or IBR, a low flow rate will hinder output.

Old steel pipes add a lot to the heat load.

Using the IBR rating allows for that additional heat loss.
Allows for proper flow through the pipes for both heating the house, and a quiet system.
Helps avoid condensation in a non condensing boiler.
Using the DOE rating can cause non condensing boilers to habe condensation, and rust out the burners or boiler due to long run times below the boilers safe min operating temperature.
beenthere is offline   Reply With Quote
Old 07-08-2009, 02:51 PM   #18
Member
 
tk03's Avatar
 
Join Date: Sep 2008
Location: PA
Posts: 167
Rewards Points: 150
Default

Boiler size


Quote:
1950 era homes aren't set up with primary secondary piping.
So if their is a problem with it. Its the installer that created the problem.
Primary secondary has nothing to do with proper near boiler piping. I am not saying primary secondary is required. If you want it do it at the time of the installation. It is very easy to do at the near boiler piping.
Quote:
If you have low flow in the pipes, doesn't matter if you use DOE or IBR, a low flow rate will hinder output.
Residentially the size of the pipe does not add much to heat load especially with ODR becoming more prevalent. As you reduce the temperature in the piping the heat loss from the piping is reduced.
You are right to state the difference between the IBR and DOE is piping loss and the basement is not as tight in the older homes. If that is the case this would be a waste of fuel. Insulating the pipes would make a lot of sense and still use DOE.
Quote:
Using the IBR rating allows for that additional heat loss.
Again do the heat loss and you want need the additiomnal btu's. There is plenty there is the fudge of the programs.
Quote:
It also causes to oversize the boiler.
Helps avoid condensation in a non condensing boiler.
Using the DOE rating can cause non condensing boilers to have condensation, and rust out the burners or boiler due to long run times below the boilers safe min operating temperature
Again this comes down to the installation and proper near boiler piping. Maybe just a bypass, circulated bypass, mixing valve or even applying any of these with primary/secondary since primary/secondary does not give boiler protection.
tk03 is offline   Reply With Quote
Old 07-08-2009, 03:32 PM   #19
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,942
Rewards Points: 3,554
Default

Boiler size


Bypasses are nice.

But most of them waste energy. Because your using some of the boilers heat to heat the water before it reaches the boiler(instead of heating the home). Which also causes lag in response to heat calls from the thermostat.

Insulating the pipes in some basements will get you complaints of cold floors. When that customer is use to those floors being heated by the pipes.

Using IBR, I have customers with warm floors, smiles on their faces, and low heating bills.

And no rust in the boiler or on the burners.
So the customer has a boiler that will last 30 plus years(excludes mod/cons).


Do what you want.

No home that comes out to a 100,000 BTU heat loss, has an over sized boiler if you use the IBR rating, which would give you a min boiler input rating of 143,750BTUs(at 80% efficiency). Instead of using a smaller 125,000 input(at 80% efficiency) for the DOE rating.
beenthere is offline   Reply With Quote
Old 07-08-2009, 03:42 PM   #20
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000
Default

Boiler size


I wouldn't want my basement heat pipes insulated
That would - as stated - mean colder floors
Colder floors will cool the house off faster
Insulating my rim joist & replacing the outside door & 3 single pain windows made my basement much warmer

I also had a 3' spare slantfin radiator installed in-line by the basement door (pipe & fins only). It has helped to keep my sons bedroom floor warmer
Scuba_Dave is offline   Reply With Quote
Old 07-08-2009, 03:45 PM   #21
Newbie
 
Join Date: Jul 2009
Location: Pittsburgh, PA
Posts: 8
Rewards Points: 10
Default

Boiler size


just want you all to know that i'm listening!
B.Y.
Bonnie Youngs is offline   Reply With Quote
Old 07-08-2009, 06:23 PM   #22
Member
 
tk03's Avatar
 
Join Date: Sep 2008
Location: PA
Posts: 167
Rewards Points: 150
Default

Boiler size


Insulation is the cheapest thing you can put into a home. It's a one time cost that keeps giving and giving. If the floors are that cold insulate them and feel the warmth even more for a longer period of time for a rather small investment. As everyone states on the INTERNET, tighten up the home first then do a heat loss. Buy smaller operate cheaper.
Oh by the way a boiler bypass saves fuel (about 8%) not wastes it. If installed per the instruction it is cool return water into hot supply water so the heat upstairs is far more comfortable, even and cheaper to make. You get a shorter run time on the thermostat. System bypasses went out with large water volume boilers. Most manufacturers require boiler bypasses today.
tk03 is offline   Reply With Quote
Old 07-08-2009, 06:27 PM   #23
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000
Default

Boiler size


I want my basement to be kept warmer
Not heated - but I'm not interested in insulating 1250 sq ft of flooring
Not to mention all the wires & plumbing I would have to weave around
And then of course if you then lose power or heat the area with your water pipes is that much colder & will freeze that much quicker

And then I lose all of that nifty storage space for my Christmas decorations between the floor joists
Scuba_Dave is offline   Reply With Quote
Old 07-08-2009, 06:34 PM   #24
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,942
Rewards Points: 3,554
Default

Boiler size


System bypass can make the occupied area heat more evenly.
Does not always save. Seldom saves.

Most people don't realize its not saving as much as they think. Because the bypass was installed when the new boiler was installed.

Bypass is best used to cover up/aid a bad piping job to the rads.

Or to protect a small boiler from being subjected to too cool/cold of a return water temp fro too long.

If, IF a bypass is installed, it should be done with themal bypass valve to minimize wasting fuel.
Bypass piping withouot a thermal control, are a watse, they bypass even when the water is up to temp, when it 0 outside.
beenthere is offline   Reply With Quote
Old 07-08-2009, 07:51 PM   #25
Member
 
tk03's Avatar
 
Join Date: Sep 2008
Location: PA
Posts: 167
Rewards Points: 150
Default

Boiler size


I think you have your bypasses backward. A system bypass will reduce the flow to the system therefore taking longer to heat the home. Reread one of your earlier posts.You stated to reduce flow reduces output. Which is correct. If you use a system bypass some of the supply water will go from the hot supply to the cool return. That would be some gallons of water going from supply to return so it does not go into the system. Thus reduced flow in the system, reduced output.
A boiler bypass will keep the flow in the system higher thus more heat output from the radiation. The system gets only as hot as needed to heat the home. You are not heating all the gallons in the system to 180f, only high enough to satisfy the thermostat.The boiler will actually operate higher than the system water.
Boiler bypass is used to protect the boiler since the mid 50's. It was invented by a guy named Gil Carlson who worked for B&G. He did a white paper explaining the application. I quote "Flue gas condensation and thermal shock are a result of extremely cold water entering the boiler or cool water at a high flow rate". The boiler bypass allows you to slow down the flow in the boiler and allow the boiler to operate as designed and not stress or condense. The boiler water gets hotter quicker and you get hotter water entering the system water to increase the water temperature of the system. We have solved many fuel use problems with a boiler bypass. All reducing the boiler run time, system water heating up quicker.
When the boiler is sized properly, and there is much more radiation than the heat loss, the boiler will run longer to heat up the home as there is too much cool water going through the boiler. A boiler bypass will reduce the flow in the boiler and allow you to run the boiler at any supply water temperature you want within reason. There are specific formulas to determine what delta T you adjust the boiler rise to. Once you adjust the proper flow through the boiler and size the boiler properly, this is the most efficient operation. If the flow in the boiler exceeds the rate to be less than a 20f delta T the water will take a long time to heat up. The flow should normally be between 20f to 40f. Slow the flow down in a boiler it get hotter faster.
The use of a thermal bypass valve would require a system bypass again which is going to reduce the flow in the system. I would only use the thermal bypass if I pipe the boiler with p/s piping.
tk03 is offline   Reply With Quote
Old 07-08-2009, 07:57 PM   #26
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,942
Rewards Points: 3,554
Default

Boiler size


A thermal bypass, will close the bypass when the boiler reaches 140F.
So the boilers full BTU output go to the home, instead of a constant reduced flow of just a bypass.

An open (non thermal controlled) boiler bypass reduces the amount of heat going to the home at design conditions.

Often, not providing the actual GPM the boiler should have.

Check out the Burnham MPO. See how its built in thermal controlled bypass works.
Although it uses a system bypass. Its done the right way. As far as it doesn't hinder boiler performance at design conditions.

Last edited by beenthere; 07-08-2009 at 08:00 PM.
beenthere is offline   Reply With Quote
Old 07-08-2009, 09:35 PM   #27
Member
 
tk03's Avatar
 
Join Date: Sep 2008
Location: PA
Posts: 167
Rewards Points: 150
Default

Boiler size


Quote:
A thermal bypass, will close the bypass when the boiler reaches 140F
If the boiler reaches 140f. If it is a large water volume system the return may be low for a long time.

Quote:
So the boilers full BTU output go to the home, instead of a constant reduced flow of just a bypass.
The boiler bypass always keeps the flow up in the system.
Quote:
An open (non thermal controlled) boiler bypass reduces the amount of heat going to the home at design conditions
.
The system water get to the temp that is required. The colder it gets outside the less the off time of the thermostat. So the system temperature remains higher at the call point.
Quote:
Often, not providing the actual GPM the boiler should have.
That is where a good tech does the formula to determine flow. Once adjusted the flow in the boiler or system does not change.
Quote:
Check out the Burnham MPO. See how its built in thermal controlled bypass works.
Although it uses a system bypass. Its done the right way. As far as it doesn't hinder boiler performance at design conditions
First off it is not thermally controlled. It is injection.
Page 29 of the I&O manual stats this
4. The MPO is designed to withstand thermal shock
from return water temperatures as low as 100F, but
prolonged return temperatures of below 135F can
cause excessive flue gas condensation and damage
the boiler and/or venting system.
Use a boiler bypass if the boiler is to be operated
in a system which has a large volume or excessive
radiation where low boiler water temperatures may
be encountered (i.e. converted gravity circulation
system, etc.) The bypass should be the same size as
the supply and return lines with valves located in
the bypass and return line as illustrated in Figures
18A and 18B in order to regulate water flow for
maintenance of higher boiler water temperature.

Even the MPO wants a boiler bypass in a large water volume system.
It is backed up with the piping drawings showing a boiler bypass.
Link to Burnham MPO website manual
http://www.burnham.com/PDF/IO/MPO.pdf
So again use DOE and use boiler bypasses when needed.
tk03 is offline   Reply With Quote
Old 07-08-2009, 09:45 PM   #28
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,942
Rewards Points: 3,554
Default

Boiler size


I have the manual already, haven't read it for a while.
Nice boiler, installed 2. But prefer another brand.

Use IBR, and you never have excesive prolonged cold return water temps.

Using a boiler bypass. After you adjust it for proper temp rise. Your still subjsct to prolonged low return temps.

Usually means your using more circ then the system should have.

If the boiler needs/should have 1 GPM for 20 rise per 10,000 BTUs.
Why use a circ that is moving more then that(say 14GPM).
And have to have a constant bypass to keep the water flow at proper GPM(say 10 GPM).

Use a thermal bypass with a circ that is moving 10GPM, and when return water temp is up, it flows full GPM. When return water temp is low, it bypasses.
beenthere is offline   Reply With Quote
Old 07-10-2009, 08:28 AM   #29
Member
 
tk03's Avatar
 
Join Date: Sep 2008
Location: PA
Posts: 167
Rewards Points: 150
Default

Boiler size


Most all of the boiler manufactures request a boiler bypass. Look it up. Weil Mclain. Buderus, Peerless etc.
Quote:
Using a boiler bypass. After you adjust it for proper temp rise. Your still subject to prolonged low return temps.
It will but it does not matter. Cool water at a low flow rate is not a problem. Cool water at a high flow rate is a problem.
The use of a boiler bypass will increase the comfort levels tremendously. The talk of the industry today is ODR and Radiant. They both operate on low system water temperatures to elevate comfort. That is what you get with a boiler bypass.
Quote:
Use a thermal bypass with a circ that is moving 10GPM, and when return water temp is up, it flows full GPM. When return water temp is low, it bypasses.
When it is bypassing the flow (gpm) that is bypassing is deducted from the total flow. This will reduce the flow in the system and reducing flow in the system which you also have stated reduces heat output. If flow of hot water to the system is reduced than it takes longer for a large water content system to heat up and gives uneven heating. It is also trying to heat the system water to 180 or whatever the high limit is set to. As we know today with the ODR use becoming so popular and will become code in a few years on all boilers, the idea is not to heat the system water to 180 every cycle, every day.
I guess the bottom line is if the manufactures want boiler bypass than why not pipe per the manufacturer specifications? Why reduce the flow in the system to reduce heat output?
tk03 is offline   Reply With Quote
Old 07-10-2009, 08:58 PM   #30
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,942
Rewards Points: 3,554
Default

Boiler size


Its a recomendation. Its not a requirement.

Bypass is seldom needed in a proper set up.

If a house only needs 10GPM, and thats what the boiler needs. No resaon for the bypass, Unless boiler is undersized. Or connected to a old gravity system with 3" pipes.

beenthere is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need Help I Have a BOILER PROBLEM mikerouse1989 Plumbing 7 02-01-2009 06:07 PM
Burnham V7 series oild-fired boiler is turning itself off Pickngrin HVAC 6 01-12-2009 09:26 PM
Boiler w. Hydronic Air & Honeywell Aquastat DanA28 HVAC 1 01-08-2009 05:21 PM
Weil McKain boiler size my5cats HVAC 1 02-24-2007 05:38 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.