Tundra 2 / Heatmax plenum temps

[Case1030]

Hi Case,
I would like to change the on off settings forthe fan on my T2 as well.

Could you please provide the specs for the ohm resistor you are using. A pic of the set up and the resistor would be very helpful too.

Thanks

Sounds good. I can help you out. What temperature are you trying to achieve?
I'll send photos later tonight. There is a chart I used that shows temperatures based on resistance I can send aswell.

 

[Case1030]

Here is the chart I used to figure out the ohm resistor size needed.

https://www.pyromation.com/Downloads/Data/385_f.pdf

Also remember it's not going to change the reading. Its just tricking the probe into thinking its hotter than it actually is. The furnace will function the exact same as stock but engage fan at 95f.

 

[Mrpelletburner]

Just something to think about. How tall is the plenum? i.e. I don’t have the extension installed.

Does the plenum height make a difference?

 

[Case1030]

Just something to think about. How tall is the plenum? i.e. I don’t have the extension installed.

Does the plenum height make a difference?

I have my plennum fully extended with the extension. I think it would help in a power outage situation and possibly heat exchanger efficiency, but not quite sure.

I'd also like to hear others input.

Edit: I think its 3.5 feet

 

[Socratic Monologue]

I do not have the extension installed -- just the single section.

 

[Gearhead660]

I have my plennum fully extended with the extension. I think it would help in a power outage situation and possibly heat exchanger efficiency, but not quite sure.

I'd also like to hear others input.

Edit: I think its 3.5 feet

The ceiling in the basement is about 7 ft. The plenum is a couple inches from the ceiling, so just about fully extended.

 

[Mojappa]

Mine is extended, total height is 32”

 

[brenndatomu]

The ceiling in the basement is about 7 ft. The plenum is a couple inches from the ceiling, so just about fully extended.

Does the T2 have a 6" CTC requirement above the plenum like most units do?

 

[Mrpelletburner]

Does the T2 have a 6" CTC requirement above the plenum like most units do?

- The plenum can be adjusted from 64" (163 cm) to 88" (224 cm) depending on ceiling height. See Section 5.1: Hot air distribution plenum height according to ceiling height.

- The start-off plenum must have a minimum height of 24" (610 mm) from the top of the furnace (X). In this case, use only the section of the plenum (the one with the 10 openings).

- The minimum clearance (C) between the top of the plenum and the ceiling is 5" (127 mm).

- The ducts minimum clearance (D) to combustible materials is 1" (25 mm).

- The ducts may pass through a combustible wall maintaining a clearance of 1” (25 mm) around ducts

 

[Case1030]

Hi Case,
I would like to change the on off settings forthe fan on my T2 as well.

Could you please provide the specs for the ohm resistor you are using. A pic of the set up and the resistor would be very helpful too.

Thanks

I switched it to a 3.9 ohm 95-96f... this is an old photo to save me from taking the circuit board off.

 

[Gbawol42]

My plenum is also almost fully extended and my connections are angled up after they leave the plenum. Did this also for the power loss situation.

I also wondered if this effected the temp enough to cycle the blower more since there was more room for the heat to rise above the temp probe at not really build up fast.

 

[nellraq]

I switched it to a 3.9 ohm 95-96f... this is an old photo to save me from taking the circuit board off.

Hello again case,

got a 3.9 resistor in......works great.

How did you determine the new kick on and kick off points?

Thank for your help. The furnace works so much better now.

 

[Case1030]

Hello again case,

got a 3.9 resistor in......works great.

How did you determine the new kick on and kick off points?

Thank for your help. The furnace works so much better now.

I used a chart that factors ohms into temperature difference. Essentially I took the difference between ohms and temperature to find the correct resistance needed to drop the cutoff point to the desired number.

Happy to hear I could return some knowledge back into the fourm. I sure have absorbed alot in the last couple years!

 

[Gearhead660]

I switched it to a 3.9 ohm 95-96f... this is an old photo to save me from taking the circuit board off.

What watt resistor did you use or doesn't it matter? The higher the resistor ohm, the lower the actual temp is when it kicks the blower on?

 

[Case1030]

What watt resistor did you use or doesn't it matter? The higher the resistor ohm, the lower the actual temp is when it kicks the blower on?

I believe it is either .5 or 1 watt. It shouldn't make much of a difference between the the two.

And yes higher the resistance lower the temperature kick on.