Furnace or Thermostat issue?

Posted by JKirkby on October 6, 2009, 2:52 pm

Hi Everyone,

I recently replaced my thermostat and upgraded from a mercury based
thermostat to an electric programmable model and am having some issues
with my furnace. Let me know what you think:

When I turn the furnace blower on "auto" and the heat to on and set a temp
above the room temperature, the heat turns on, the fan turns on, and the
house is brought up to temp. The furnace kicks off and the fan keeps
running. When I turn the thermostat to "off" from "heat", the fan still
runs. The only way to get the fan off (ironically) is to turn the fan
setting to "on" from "Auto" and the system shuts down.

When I installed the new thermostat, I don't think I diagrammed the old
wires (stupid, I know) but could incorrect wiring be causing this problem?
If not, do you think this is a fan/limit control issue? This is an older
furnace (an Imperial II from GE, at least 15 years old MODEL NUMBER
21LU130K28) and the thermostat is a honeywell RTH111/221.

Any advice here would be appreciated.

Sincerely,
-------------------------------------
James Kirkby

Posted by Real Pisser on October 6, 2009, 3:57 pm

> Hi Everyone,
> I recently replaced my thermostat and upgraded from a mercury based
> thermostat to an electric programmable model and am having some issues
> with my furnace. Let me know what you think:
> When I turn the furnace blower on "auto" and the heat to on and set a temp
> above the room temperature, the heat turns on, the fan turns on, and the
> house is brought up to temp. The furnace kicks off and the fan keeps
> running. When I turn the thermostat to "off" from "heat", the fan still
> runs. The only way to get the fan off (ironically) is to turn the fan
> setting to "on" from "Auto" and the system shuts down.
> When I installed the new thermostat, I don't think I diagrammed the old
> wires (stupid, I know) but could incorrect wiring be causing this problem?
> If not, do you think this is a fan/limit control issue? This is an older
> furnace (an Imperial II from GE, at least 15 years old MODEL NUMBER
> 21LU130K28) and the thermostat is a honeywell RTH111/221.
> Any advice here would be appreciated.
> Sincerely,
> -------------------------------------
> James Kirkby

Captain Kirk,

how many wires were hooked up to the old mercury thermostat? was it one of
those YoYo types? prepare to be treated here.

Posted by JKirkby on October 6, 2009, 5:14 pm

JKirkby had written this in response to
http://www.thestuccocompany.com/hvac/Re-Furnace-or-Thermostat-issue-38631-.htm
:

Captain Kirk,

how many wires were hooked up to the old mercury thermostat? was it one
of
those YoYo types? prepare to be treated here.

Hi There - thanks for the warning :)

There were four wires with the old thermostat. After disconnecting them
and realizing that I should have paid attention (duh), I used the old
thermostat to map the new connections as best I could as some of the old
wires were still leading to the connections.

The old thermostat was rectangular and used mercury to tell the temp and
had the same setting as the honeywell. It was just old as dirt and not
programmable.

-------------------------------------
James Kirkby

Posted by JKirkby on October 6, 2009, 5:13 pm

JKirkby had written this in response to
http://www.thestuccocompany.com/hvac/Furnace-or-Thermostat-issue-38630-.htm
:

JKirkby wrote:

> Hi Everyone,

> I recently replaced my thermostat and upgraded from a mercury based
> thermostat to an electric programmable model and am having some issues
> with my furnace. Let me know what you think:

> When I turn the furnace blower on "auto" and the heat to on
> and set a temp
> above the room temperature, the heat turns on, the fan turns on, and
> the
> house is brought up to temp. The furnace kicks off and the fan keeps
> running. When I turn the thermostat to "off" from
> "heat", the fan still
> runs. The only way to get the fan off (ironically) is to turn the fan
> setting to "on" from "Auto" and the system shuts
> down.

> When I installed the new thermostat, I don't think I diagrammed the old
> wires (stupid, I know) but could incorrect wiring be causing this
> problem?
> If not, do you think this is a fan/limit control issue? This is an
> older
> furnace (an Imperial II from GE, at least 15 years old MODEL NUMBER
> 21LU130K28) and the thermostat is a honeywell RTH111/221.

> Any advice here would be appreciated.

> Sincerely,
> -------------------------------------
> James Kirkby

Hi There - thanks for the warning :)

There were four wires with the old thermostat. After disconnecting them
and realizing that I should have paid attention (duh), I used the old
thermostat to map the new connections as best I could as some of the old
wires were still leading to the connections.

The old thermostat was rectangular and used mercury to tell the temp and
had the same setting as the honeywell. It was just old as dirt and not
programmable.

-------------------------------------
James Kirkby

Posted by Steve on October 6, 2009, 9:14 pm

I don't suppose that you actually *READ* the operating manual??? nope??
didn't think so.

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