Newmac cl86 wood/oil furnace questions...

[CowboyAndy]

Okay, we have been burning almost 24/7 for a few weeks now and I have a few issues.

First, overnight burns. We've been trying different things, and have had some success. But my concern is this: When I get up in the morning, the house is between 3-6 degrees cooler than what the thermostat is set for (the tstat just controls the draft inducer fan). But when I go down to the basement and open the furnace door, there is a good amount of coals and almost melts my face off. The plenum is warm/hot, warmer than the first time the blowers come on after first lighting it. Why arent the blowers coming on after an all night burn when the temp of the plenum feels warmer than other times it comes on? The hi/low limit switch that controls the blowers is mounted on the BACK of the plenum, pretty low and towads the outside edge. Is this the correct placement for it?

FYI, I load it up at 10pm, set tstat to 73-74 and close the slider for the draft fan half way. I get up at 5:30 am to reload it.

Also, the blowers seem to run in pretty short cycles, usually they run for about 30 seconds to a minure, about every 5 min. Again, could this be caused by the placement of the hi/low limit switch?

 

[JustWood]

What is the low limit switch set at? Mine is at 105.

 

[smokinj]

What is the low limit switch set at? Mine is at 105.

mine is set at the same 105

 

[CowboyAndy]

I will check this afternoon when i get home.

What should the hi limit be set to (is that adjustable too?)

 

[JustWood]

My high setting is at 155. Your manual should have the correct settings. I have experimented with my low setting . I adjust it to 115-120 durring shoulder season burns to keep the firebox hotter and keep creosote from forming. Once we get real cold weather I adjust it back down to 105 because the furnace runs wide open more often and thus keeps the chimney cleaner.

 

[CowboyAndy]

Okay, checked it yesterday. first tab was at 100, second was at 120. hi safety limit was at like 250ish. I talked to my uncle who is a hvac contractor in Mass, he suggested 2 things to make it more efficiant.

I had mentioned that it seems like it short cycles... he suggested adjusting the pulley for the blowers, saying that it was moving too much air, thus short cycling.

He also suggested adding a second fan switch, placed in closer proximity to the firebox, as the current fan/hi limit switch is located at the rear of the furnace but the fire box is all the way in the front. He said to wire it in parrallel, and that would make it more adjustable and controllable.


Thoughts?


FYI, even though it was a little warmer last night (40*, has been low 30's), i loaded up as usual last night and left it with full air, tstat set to 74. I went down at 5:30 this am and there was a good 4-5" coal bed, blazing hot and the house was 76.

 

[JustWood]

Start with simple stuff first. Check manual or call Newmac for correct settings. If they are set correct I wood experiment with the adjustment. If the limit switch is far away from the firebox I wood try lowering the low setting from 100 to 90 or 95. That will make your fan run longer. Seems if your face is melting off when you open the door and the fan is off then the low limit is set to high.