How to set up IC burners to run on low pressure

Paul_11

I have some large buildings, where with orafices, quick vents, and a vaporstat I can get them to run on 1 pound pressure.

My problem is with the burners. Many times these large boilers have large #4 oil IC fully modulating burners.

When I get done with my work they never go to high fire anymore and don't run very long, so there is no modulation going on.

The property managers and coop presidents tell me that while the building's occupants are very happy, and very comfortable, they aren't saving much if any money.

When I first started hearing this a few years ago, I was reluctant to believe them. However, I have seen this latest IC burner go on and off every 5 or 10 minutes. It is not running much, but it is definitely not running efficiently. It does not stay on long enough to reach steady state efficiency.

I am not a large oil burner guy, and the oil guys working on these burners either have no clue or are having lots of difficulty.

Has anyone figured out a way to utilize the modulation capabilities of the IC burners while running at 1 pound pressure.

Honeywell says they don't make a vaporstat that contols modulation. They do have the L91, but the only operate at higher pressures.

I could suggest replacing the burner with a smaller one, but still I can only downfire an oil burner in NYC by 20%.
Installing a Weisshaupt at 80% of the boiler rating is my next option.

What am I to do?

Paul
A Real Good Plumber, Inc.





<A HREF="http://www.heatinghelp.com/getListed.cfm?id=236&Step=30">To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"</A>

Blackoakbob

a couple ?...

Hi Paul are these burners air pressure atomizing and do they have a potentiometer for controling the firing rate? It may be possible to put a manual pot where the existing firing rate control is and dial it down to a low fire rate which would take over after startup. Then just manually adjust it to the lowest point at which it would heat the building and allowing it to run longer and longer as the demand increases. Not to say that someone would have to do combustion tests to make sure of proper draft and stack temp is maintained. Run it by your burner people. Best regards,

EBEBRATT-Ed

The efficiency of a large burner running on low fire is poor. Thats why on many jobs they jacked up the steam pressure and let the burner come on at 1 psi and off at 10 psi to reduce short cycling and modulated it in between.

Try down firing the old boiler as much as possible. Inc steam pressure wil reduce short cycling (I know you don't want to do this)

The best you can do is compromise. The only alternative is boiler replacement.

Thats why oil and gas fired burners screwed up steam systems.

They worked great on coal.

ED

Paul_11

Thanks blackoakbob & ebebratt for your thoughts.

The burner is an atomising burner with full modulation, but anything but low fire causes short cycling.

I think that you are right, ebebratt about IC's not running very efficient on low fire.
I do run some Weishaupt WL burners on low fire and they perform very well.
The boiler is a 9 year old Rockmills, so I hate to replace it.

I will have to make some calculations and see if replaceing the burner with a Weishaupt and down fireing the boiler 20% gets me to where I want to be. If not I will suggest they replace the boiler.
When you are spending $40,000 to $50,000 on oil a year, you have some room to work with regarding a burner or even a boiler replacement.

Thanks again for your thoughts.
Paul
A Real Good Plumber,Inc.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Tom_80

Burner

We've done this before and had to set up the burner for about a 50% derating, then the modulation of the burner comes back into play and you start to see your effieciency rise.

Paul_11

in NYC the DEP only allows a 20% downfiring

I wish it weren't so.
Paul
A Real Good Plumber, Inc.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Darrell_3

ic burners

it would be nice to list the boiler hp and the model of the burner however the condition you're having is common in many buildings today, there is no need to replace the burner at this time it seen you're working with a very tight system based on your information, i would do the following drop your firing rate by mean of changing the metering pin install a second pot to operated the burner modulation and another area to look would be to operated the heating system on your heat timer indoor sensor to regulated the amount of heat you want in the system there are many option to at least deal with this problem with a IC burner there is really no reason to replace the burner.

thank you,
harry 5332

good luck paul

Darrell_3

that only true if the job has been file to operate at a design firing rate. you can either upgrade or downgrade your firing rate and and submit paperwork work to DEP for a new certificate of operation.

good luck harry 5332

master02

ic set up

i believe you miss the question, i am aware that the paperwork must be file but no where here did it mention that, the author was asking a question


go back and read what he is looking for, gamercash

oil-2-4-6-gas

i do 90% commercial and of that probably 60% is IC Burners air atmozing unfortunately in NYC--(im in westchester but we do some DAR tests in NYC) the size of the burner has to match the boilers size --and the inspectors look at the stamped # on the metering pins --///you have some options though --you can run the burner in manual low or 1/4 fire (you will have to set--up with an analyzer) you can get 80% BUT you have to readjust for the DAR test --you need to adjust the differential on the pressuretrol to go off on pressure but drop a lot before coming back on. you can add a delay timer to keep the burner off for a minimum time /// you can change the stroke on the mod-motor to reduce the amount of air and oil for high fire --But you will have to return it to 20% low fire and 80-100% on high before the DAR test --you can change the pin for the test --and readjust ----or talk to someone who has been working with IC's for a long time for the "secret"

oil-2-4-6-gas

the 1 pound modulating control does not exist --if it had a spring return mod motor it would be simple --just a switch but maybe you can wire something to work ----a reverse acting vaporstat to a relay spdt by-passing the L91 --just a thought i never heard of a reverse acting vaporstat and not sure if the relay would work but i would try it

Blackoakbob

another way

I did have another suggestion, you could put a Spence type pressure reducing valve on the outlet of the boiler set at the delivery pressure, set the boiler at max and use the boiler and near boiler/header piping as a steam chest to store steam which would be recharged with long on and off cycles with the boiler. Good luck

tim smith

Maybe talk to IC about converting over to electronic trim as

long as they approve the turn down rate you want. I would check this first to make sure on how far you go down as it may be for not if you can't really get down to where you need.