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-   -   Boiler Problems @ LowThermostat Setting (http://www.diychatroom.com/f17/boiler-problems-lowthermostat-setting-33103/)

Ron6519 12-03-2008 05:38 PM

Boiler Problems @ LowThermostat Setting
 
Have a friend with a weekend house in upstate NY. The 8 year old Burnham hot water boiler operates flawlessly at 65-70 degree settings. When set at 55 degrees(when no one is there )the Carlin primary trips. It will come back on when the reset button is pushed and stay on with the thermostat set higher.
Last year the boiler tripped in January. Pipes froze and caused $65K in damages. Safeguards are now in place to prevent that happening again, but the boiler is still an issue.
The service guys have been out there at least a dozen times with no solution. I've recommended that she change companies, but that's up to her.
Are there any temperature sensitive components on these units?
Ron

beenthere 12-04-2008 05:18 AM

Not really, as far as to cause this problem.

But, as the oil and air get colder from the low temp setting. Its harder to ignite the oil. So it could be that its set up to use just a little too much combustion air.

Many times, techs will over air the flame to get a 0 smoke. This can cause it not to light when its cold.

Ron6519 12-04-2008 08:04 AM

Well, Monte the service tech came by yesterday morning for another ,"no heat" call. He pulled out the nozzle assembly and adjusted the electrode position and some barrel adjustment on the side of the gun.
This morning after setting the thermostat down to 55 last night, I woke up to a house temp of 55 and the boiler hadn't tripped. I raised the temps to 68 and it fired right up.
The only variable that's different is the outside temperature. It's about 15 degrees warmer today then yesterday.
I'll try the same experiment tonight and see if still works tomorrow.
This is a direct vent boiler with a dedicated air intake directly to the gun. The flexible flue pipe gently arcs outside about 10 feet from the boiler.
I'm a little optimistic at this point, so I'll enjoy the moment.
Appreciate the reply.
Ron

beenthere 12-04-2008 10:02 AM

Electrode and combustion air settings are more important on direct vents then natural draft units.

tk03 12-04-2008 02:01 PM

On direct vent equipment I would like to see a CO2 of about 12-12.5%. As Beenthere says cold air and oil can be a problem. Many tech's want to set the CO2 at 10 - 11 %. As the air gets colder it will contain more oxygen. Ask the tech what the C)2 is or check to see if it is written down there somewhere.

Ron6519 12-04-2008 03:57 PM

Quote:

Originally Posted by tk03 (Post 193773)
On direct vent equipment I would like to see a CO2 of about 12-12.5%. As Beenthere says cold air and oil can be a problem. Many tech's want to set the CO2 at 10 - 11 %. As the air gets colder it will contain more oxygen. Ask the tech what the C)2 is or check to see if it is written down there somewhere.

These are the numbers from the July 2008 tune-up
0 - 01 - 350 - 11 1/2 - 84 3/4

I don't know what the first two numbers are, but I guess the:
350 = Stack Temp
11 1/2 is the CO%
84 3/4% is the theoretical efficiency

The boiler has been adjusted twice since then. According to Monte, the service tech, the last adjustment(10/28) was incorrect for the AFll 150 gun.
I'm thinking, Monte will be the go to guy for future tuneups and repairs.
We'll see what happens when the exterior temps get into the low 20's and the teens.
Thanks to the informative posts here, I have a better sense of at least some information about this boiler and can ask some relavent questions of the service guys.
Thanks.
Ron

beenthere 12-04-2008 04:18 PM

The "0" is your smoke reading.
The "1" is your over fire draft.
The "350" is stack temp.
The "11" os CO2.

With those readings. You had too much combustion air.

Ron6519 12-04-2008 04:35 PM

Quote:

Originally Posted by beenthere (Post 193842)
The "0" is your smoke reading.
The "1" is your over fire draft.
The "350" is stack temp.
The "11" os CO2.

With those readings. You had too much combustion air.

I'm finding out these direct vent/intake boilers are very sensitive to tuneup adjustments, far more so then the old basement air intake I used to have.
Ron

beenthere 12-05-2008 04:48 AM

Yes they are.
Unfortunately, some techs don't seem to understand that.

Ron6519 12-05-2008 06:54 AM

Quote:

Originally Posted by beenthere (Post 194145)
Yes they are.
Unfortunately, some techs don't seem to understand that.

Well, so far so good. Woke up to the set 55 degrees and the boiler started right up when the thermostat was raised to 68. Outside temps are 28 degrees.
Ron


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