Furnace Issues

[ExtraSlow]

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Looks similar to mine. You can close it off completely to increase humidity in your house, or open it more to lower the humidity. Note: the flap inside is probably cut off so you can’t close it completely. They are less than $2 at Home Depot.

The low spot in the flex duct probably has a gallon of water or ice in it.

I replaced the circle flap thingy in the valve to one that seals nearly completely. I had some problems with skunks hanging out near that intake and stinking the house up. So that's about as closed as it can get.

[sabad66]

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That's why you should have three furnaces for true redundancy/failover protection.

Might as well go yolo and go with a raid6 furnace setup for maximum redundancy

[ZenOps]

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Love these cold air temps. I have some serious frosting happening on the cold air intake, and I assume that's why my floor around the furnace is soaked. Note this is not the combustion air intake, but one that ties into my cold air return line.
Attachment 89037
Attachment 89038

Should be a cheap and easy fix, the black line is draining properly, but the white must be extended to drop straight into the drain. You want the moisture in the rest of the house, not right beside the furnace.

Fitty cent fix is to get a smaller aluminum pie plate (like those Swanson chicken pies), and cut holes in same pattern as whatever drain you have, as well as a couple bigger holes of which you shove the two drains into (try to make sure it direct drops into the drain) Check every now and then to see if there is moisture under the pie plate, if there is its doing its job (condensing warm water and dropping it back down drain)

[benyl]

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That's why you should have three furnaces for true redundancy/failover protection.

That resembles my setup.

Two furnaces and a boiler to heat the DHW, basement, washroom and garage floors.

[ExtraSlow]

Not really an urgent issue, but I'm balking at the cost to install one of those fancy lower power blower motors, so I'm looking at what I have now.
On my carrier 58STA, there appears to be a few different blower motor speed settings possible. You move around the wires, as per the manual :



Now I can't tell any difference in fan speed between heat, cool, or the 24/7 circulation. If there's any difference, it's subtle as hell.

Mine is set with this following:
BLW: White
COOL: Black
HEAT: Blue
SP1: Red
SP2: none.

So, if my goal is slower, but not off, fan in circulation mode, and lower energy use overall, should I be messing around with this, or just spending the $250 on the fancy Mars Digi-motor?
Don't want fan speed any lower on cool for sure. I already have occasional icing issues.

[Darell_n]

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Not really an urgent issue, but I'm balking at the cost to install one of those fancy lower power blower motors, so I'm looking at what I have now.
On my carrier 58STA, there appears to be a few different blower motor speed settings possible. You move around the wires, as per the manual :



Now I can't tell any difference in fan speed between heat, cool, or the 24/7 circulation. If there's any difference, it's subtle as hell.

Mine is set with this following:
BLW: White
COOL: Black
HEAT: Blue
SP1: Red
SP2: none.

So, if my goal is slower, but not off, fan in circulation mode, and lower energy use overall, should I be messing around with this, or just spending the $250 on the fancy Mars Digi-motor?
Don't want fan speed any lower on cool for sure. I already have occasional icing issues.

The most noticeable change will be the amp draw, if you put a clamp meter on it at different speeds. I physically move the wire for COOL between high and low speed in summer and winter. It can be done with an external relay, just haven’t gotten around to it.

Edit: Your manual shows continuous blower on HEAT speed, so it is already on the lowest horsepower possible with the fan only running. My Carrier furnace is the opposite.

[cdnsir]

Not quite an issue and more of a tuning question, hoping you guys can help.

So couple of years ago the mid-efficiency furnace was replaced with a high-efficiency one. Was told these don't run as hot and more fan circulation was required and I just left it at that.

Fast forward to now, I'm wondering if maybe there are settings I can adjust to get it to warm up quicker. It consistently takes just over 1 hour to get the house to warm up 2 degrees, with the floor register heating up to 40-45 degrees (depending on location) while the fan is on second stage. Is this normal?



I was told the thermostat and/or the furnace determines the most efficient settings to use for hitting the target temperature. But looking into the manual, turns out there are some settings I can adjust via bluetooth (yea this was a wtf moment...). Has anyone tweaked settings like these before? I basically want it to run hotter (if that's even possible) and adjust the 2 fan settings to run at an optimal setting that can push lots of air out without sounding like a jet taking off.

[16hypen3sp]

Woke up this morning to my first ever furnace problem in my place.

Lennox model ML193UH Series

It seems it's not meeting one of its start up requirments.

Inducer motor starts and igniter begins to get hot and glow. Next stage should be ignition but it aborts before any main burner flames.

From the installation manual, start up sequence is as follows:

1 - When thermostat calls for heat, combustion air inducer
starts.

2 - Combustion air pressure switch proves blower operation. Switch is factory set and requires no adjustment.

3 - After a 15-second prepurge, the hot surface ignitor energizes.

4 - After a 20-second ignitor warm-up period, the gas
valve solenoid opens. A 4-second Trial for Ignition period begins.”

5 - Gas is ignited, flame sensor proves the flame, and the
combustion process continues.

6 - If flame is not detected after first ignition trial, the ignition control will repeat steps 3 and 4 four more times
before locking out the gas valve (“WATCHGUARD”
flame failure mode). The ignition control will then automatically repeat steps 1 through 6 after 60 minutes.
To interrupt the 60-minute “WATCHGUARD” period,
move thermostat from “Heat” to “OFF” then back

Anyone have any ideas? It was working fine when I went to bed last night. Comb. air press switch maybe?

[ThePenIsMightier]

Did you kill the power to it for 30 seconds and then turn it back on?

[dj_rice]

Flame sensor. 9 times out of 10 is what ExtraSlow would say

[16hypen3sp]

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Did you kill the power to it for 30 seconds and then turn it back on?

Yes, first thing I did. Turned power off, removed top access panel, turned power back on, set thermostat to call for heat, inducer turned on, igniter starts to glow, suddenly aborts.

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Flame sensor. 9 times out of 10 is what ExtraSlow would say

There are no flames. It's not getting to that point. I took off the tubes on the pressure switch and blew thru them to ensure they were clear and they are. So maybe a problem with the switch itself? Maybe the gas valve is fucked?

[ThePenIsMightier]

Is this a new enough unit to give you error codes based on the ~Morse Code blinking lights?

*I hope you replaced top access panel before attempting restart. They hate having shit open.

[vengie]

Agreed with flame sensor - remove it, buff and clean with sandpaper and re-install.

Had a very similar issue on my furnace 2 years ago.

[ExtraSlow]

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Flame sensor. 9 times out of 10 is what ExtraSlow would say

It's usually something really small and simple and cheap. I am a diagnosis noob, but hey it's a weekday today, call up AMRE or your favourite local parts supplier and spend a few bucks on the cheap parts so you have the chance to test things. And yeah, my furnace had the morse code blinky lights that kinda helped.

[ThePenIsMightier]

AMRE also has great YouTube videos of common fixes.

[16hypen3sp]

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Is this a new enough unit to give you error codes based on the ~Morse Code blinking lights?

*I hope you replaced top access panel before attempting restart. They hate having shit open.

Yes but no error is being displayed. It's just a solid red LED which means 'Normal Operation' but I will let the furnace keep doing its attempts to ignite to see if it does go into WATCHGUARD. Wife went to work early this morning and when she left, she thought it sounded weird.

[16hypen3sp]

Alright I've counted 9 ignition attempts and no WATCHGUARD mode came in. No error lights on the board. It just keeps trying over and over. The gas valve isn't opening so there's no gas to the burners. Step 4 in my post above is where things are going wrong.

I ran outside and made sure no motherfuckers were pranking me by closing the main gas line valve. Fired up my gas fireplace (which is always off including pilot) to ensure good gas flow and bring up the temp of the house a bit.

[littledan]

Try hitting the gas valve medium hard. The solenoid might be gummed up sticking closed?

[ExtraSlow]

My other tip for anyone who's got furnace issues is to call your local equipment rental place and reserve 3 of the high-output 110V heaters for pick-up before the weekend. That way, if your repair is slow, you can be assured you'll make it without a dangerous situation. Also probably worth having a couple of the cheapest 1500W heaters sitting on a shelf somewhere nearby.

Had a family member lose a furnace in -35c weather, and some portable heaters kept things safe for a few days until the real repair could be made.

[16hypen3sp]

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Try hitting the gas valve medium hard. The solenoid might be gummed up sticking closed?

Haha, you read my mind. I've solved many o' problems at the large industrial plant I work at with the precision percussion adjustment method. Unfortunately, it's not helping me out on this one. I have the pressure switch out. So I'm going to get a new one of those right now and start there. Really don't want to fuck with the gas valve assembly.... So I'm just hoping it's the switch because it's an easy fix.