DRAFT

Jim Davis_3

Draft regulator might be fine but it is either too small or set improperly. The whole purpose of the draft regulator is to prevent from happening exactly what you have listed. It is supposed to relieve the excess draft(draft is always higher in the winter than the summer)and not allow it through the equipment. If it is wide open with the readings you have listed then it is too small for the chimney.

Toddid Goldsmith's

DRAFT

I SERVICED MY BOILER AUGUST 27 07,RAN A COMBUSTION TEST. HAD A 0-SMOKE, CO-11%, STACK TEMP-400, ADJUSTED THE DRAFT REGULATOR, HAD A -.02 OVER THE FIRE,AND -.04 AT THE BREECH. THE OUTSIDE TEMP. WAS IN THE EIGHTIES, WHEN I RAN THE TEST. JUST CHECKED THE DRAFT AGAIN, OUTSIDE TEMP, IS ABOUT TWENTY FIVE, GUESS WHAT I FOUND. I HAD A -.04 OVER THE FIRE, AND -.08 AT THE BREECH.DRAFT REGULATOR IS FINE. IF YOU SET EM UP IN THE SUMMER, DON'T MEAN THEY ARE GOING TO BE RIGHT IN THE WINTER.

Darin Cook_5

CO2

The temperature of your incoming combustion air is going to dictate what to set the CO2% at.

TIP: It will not be 12% CO2 on set-up all the time!





Darin

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Bob Bona_4

Yup

do not max out your CO2 settings in the summer. 9 times out of 10 they will change for the higher in the winter. Give some cushion for cold oil, lint/dust build up, air changes..You look for the sweet spot when tuning burners.

Toddid Goldsmith's

DRAFT

ROOM TEMP. WAS THE SAME, COMBUSTION AIR TEMP WAS THE SAME. BOILER AND OIL TANK ARE IN A ROOM THAT IS A CONSTANT 70 DEGREES, +OR- THE DIFERENTIAL IN THE T-87.I ADJUST TO A 0 SMOKE, THEN DROP THE CO2 10% FOR LINT AND OTHER DEBRIS.

Dick Charland

Draft will change and often dramatically during the winter. Outside air temperature, barometric pressure, humidity and chimney height/location all factor in. The difference is caused primarily by the change in outside temperature. The colder the air gets outside the larger the difference in temperature and the higher the draft. If the combustion air is connected to the burner it is recommended that when setting up, testing the burner in winter that you not maximize the settings. The colder the air gets, the more dense a cubic foot of air becomes holding more oxygen. As the air warms up each cubic foot of air would hold less oxygen and will pose a problem as far as a clean fire. This helps to explain the problems often seen with equipment not properly set up during warm weather and the resulting service calls as cold weather develops.

DEREK_12

DRAFT

I whent to a call to day. The chimney man no namese, could not put a 7in liner in this 40ft chimney so he put a 3in and a 4in liner in. These two where hooked up to a 7in smoke pipe this boiler is a pressure fired with a carlin 301 crd with a 3.50 nozzle. with out the boiler running the draft is -.01 start it my draft gauge gose to +12. My qestion is is there a fix? I know a 3&4 dosn`t = 7 in lineres.

DEREK_12

DRAFT

I whent to a call to day. The chimney man no namese, could not put a 7in liner in this 40ft chimney so he put a 3in and a 4in liner in. These two where hooked up to a 7in smoke pipe this boiler is a pressure fired with a carlin 301 crd with a 3.50 nozzle. with out the boiler running the draft is -.01 start it my draft gauge gose to +12. My qestion is is there a fix? I know a 3&4 dosn`t = 7 in lineres.

Jim Davis_3

3" + 4" liner = maximum 5" flue. Why did you need a liner?

This is a dangerous situation that will allow fumes into the building. Get someone there as quick as possible to make the proper recommendations.

Bob Harper

Actually, a 3" liner plus a 4" liner does not equal one 5 inch liner. The cross-sectional area of a 3" is 7". A 4" liner is 12.6 sq.in. for a total area of about 20". A 5" liner is about the same but, the effective area is less. Moreover, you have to de-rate flexible liners by 20% each. Simple fluid dynamics: when you double the area of a conduit, the flow capacity increases by the cube--not just double. Any firefighter knows this. This is why one large liner or conduit is always better than two of equal cross sectional area.

How was this sized? By the appliance collar or firing rate?

If they say they cannot get a 7 inch liner down, that probably means it would require flue tile removal, which is a royal P.I.A.
I'm curious with Jim, what was the reason for the liner?

DEREK_12

BOB Thank you for the reply. This chimney guy from mass looked at the breach colar witch was 7" not the boilers max firing rate. He came back the next day and removed the liners and lost a customer for good reason. Wow what we see out here in the field.

Toddid Goldsmith's

Draft

I took a pump operators course when I was involved in the fire service. We were talking about friction loss, and the volume of water that would pass through different size lines.The question of whether 2- 2 1/2" lines would supply the same vollume as 1-5" line came up. The instructor explained to us that they would not.Then one the blackboard he drew a 5" circle, then he drew 2 2 1/2" circles inside the 5" circle.When I saw that diagram, it sure sunk in. Try it with a 7", and a 3"and a 4" circle.