Print

[oaky]

A couple of weeks ago, I upped my boiler temp from 185, to 190.
Since then, there has been a churgling sound from my Taco circulator, it only does this when the boiler overshoots the set temp, starting at about 195+, then quits when the temp comes down past around 195, then all is quiet with the circulator until it comes up past 195 again. The churgling sound can be heard in my basement through the lines. Odds are, that there is air trapped in the circ, snapping the valves on/off in all locations doesn't seem to do the trick. It worked when I initially filled the boiler with water for the first time this fall.

The BL-2840 only overshoots the set temp on windy days, otherwise, the low/high set temps are tight.

[slimjim]

Try backing the temp down by 3-5 degrees!

[oaky]

Having the temp set at 190, keeps the creosote under control for my BL-2840. With these high winds, I just closed the air adjuster for the draft blower to about 1/2" open until the winds die down.

When I heard that sound while in the basement, I would go out and unplug the circulator for around 30 seconds, plug it back in, and it was quite for a moment, then I would repeat this process a total of 3 times, and it finally remained quiet, maybe coincidental, I did notice the boiler temp tumbling down right afterwards, thinking it may have gotten better circulation now.

Whenever I used to start my pressurized Aqua-Therm for the first in the fall, there would be poor water circulation, so I have done the same procedure mentioned above & it always worked. I'll continue this procedure tomorrow & see if it was coincidental or not. I have the stove all stoked up & planning to stay indoors for the rest of the night.

[oaky]

Closing the blowers adjustable air intake to within 1/2", didn't help, my high temp limit switch (set at 200f) on my gas furnace blower kicked on, temp in the house is 80, t-stat set at 77. Went out to the owb, the temp boiler temp read 206F & the circulator pump was churgling away, smelling quite hot. I went ahead and tried the unplugging/plugging in method, seemed to have helped again. I backed off my set boiler set temp from 190 down to 180.

[Jwood]

So what is causing these boilers to creep up with the high wind just curious?

[oaky]

In my case, there is a backdraft cover inside the air box that prevents any firebox exhaust from escaping towards the draft blower. When the winds are blowing, I can hear the this cover opening & closing during wind gusts. I would assume this is the cause. Checked all door gasket, they are all tight.

[Jwood]

So would everyone say that the air is pushing through the blower or is it creating a siphoning effect on the stack?

[slimjim]

I think more than likely it is turbulence moving the air in both directions, not sure it would do the trick but a Barometric damper installed at the Tee or a motorized damper that automatically closes when the blower shuts down installed at the stack would do the trick and reduce stack temp losses!

[oaky]

My previous owb temp would overshoot my set point on windy days, Installed a manual damper (my first 2 feet stove pipe was black single wall pipe) and this took care of the problem, of course, this isn't possible now with all class A chimney (5 feet), unless going with Slimjim's suggestion.

I'm still stumped on what is causing that noise in my circulator when the water temp goes over 95 degrees.

[jreimer]

Hi Oaky,

What's your altitude where you live?  My guess is when the water temps are that high and the pump is running there is a reduced pressure in your lines enough to cause the water to flash boil in the pump and create steam bubbles.

[oaky]

I'll have to admit, that's a new one on me, jreimer that water could flash boil inside the circulator, causing steam bubbles, I'm not saying that this can't occur, because it could very well be that's causing the sound above 195F. I don't recall ever hearing this sound on my previous owb, it had the same Taco 007F5 circulator, nothing has changed on my current setup other than adding an extra 10' to my line run, an inline sediment filter & a few extra ball shut off valves.

Not sure about the altitude, but the town about 30 miles south of me, I believe is at sea level, they're always flooding out.

[jreimer]

It would only take a 3 PSI drop in pressure somewhere in the system or circulator for the water to boil at 195.  Or maybe the water is a little hotter at the top of this boiler than 195? 

[oaky]

It would only take a 3 PSI drop in pressure somewhere in the system or circulator for the water to boil at 195.  Or maybe the water is a little hotter at the top of this boiler than 195?

On occasion, I can hear the water sizzling around the secondary heat exchanger when 200-205F, maybe the water temp sensor is located too far from the hot spot. I have a separate water temp sensor attached to the supply/return lines behind the BL (attached to a brass fitting), that water temp sensor usually reads about 6 degrees lower on the supply line than the Johnson digital readout, not certain which is correct or if both are correct sense the temp sensors are in two different spots.

[oaky]

No one has ever heard a churgling/scraping sound coming from there circulator behind their owb when boiler water temp goes over 195F then becomes quiet again when temp drops below 195?

[slimjim]

Are you seeing any visible steam from the vent tube?