Modern furnaces need to go through series of stages before they will light. These stages check the various safety systems. They require electricity for sure….
A pure travesty that should not be allowed by any Building Code - no matter what supposed advantages might be perceived to arise on the score of floor heating, or otherwise - IMHO.
My understanding is that is actually required by code, because the exhaust is not warm enough to continue up to the roof height, causing fumes to potentially back up into the house. When we got our last water heater, the installer had to go to one step below most efficient so that we could use existing flue and not have to cut through the brick wall at the front of the house.
My brand new HE combi boiler does vent through my existing chimney. I paid extra for it. They dropped a pvc liner down it and connected. Inlet is low and just on the outside wall of the house (Optional, can be just inside, but fresh air intake is best).
Not all chimney can work though for HE exhausts, I got lucky
Our furnace has an exhaust fan to stop that from happening. Seems like that method could be use in other applications to avoid a vent being set at a level that it could be blocked by snow.
I suspect that code specifics vary by local, and could very likely have changed since mine was installed. Also possible that such a solution was not possible in my house.
Also possible that installer was only slightly less ignorant than I!
My exhaust vent was directly below the intake, PVC like yours. In very cold temperatures, the steam from the exhaust vent rose up into the intake vent and created ‘snow’ in the outer 3-4" of the PVC, which blocked it. The furnace wouldn’t run due to lack of intake air. I learned to check that pipe and clear it often when temps fell below 5 degrees.
I have never studied any sort of code; only learned for very specific applications for something I was doing.
But having studied physics, that just sounds dumb! Even without cold temps, that would mean (since warm air rises), that your intake would be sucking in some amount of your exhaust. That means that in best conditions, it’s getting air with less O2, and more CO2, which is not what you want for good combustion. Realistically, the loss of efficiency is probably very low, but still real.
Is there any sort of good reason to put them this way?
Aaaaand the thing is on the blink again. Farted out last night, flipped the breaker a few times (it wasn’t tripped this time), and I was warm this morning.
I’m gonna call someone about this, 'cause 1, I don’t know the first thing about HVAC, and 2, I don’t want to crawl under the house again. Having my house explode because of those two things would be embarrassing.
Yeah have someone tune it up.
One thing to check real quick. Have you changed your air filter recently? I saw one unit completely lock out cause the air filter was SOLID. YES some systems have air flow sensors!
I had a furnace with a bad induction motor bearing. The induction motor runs the fan that helps to induce the draft required to exhaust the combustion gases.
The furnace would run fine as long as it didn’t need to run too long. On a very cold day the furnace stopped running. It didn’t trip the breakers at the panel. It did trip an internal sensor that had to be manually reset (by turning power off/on).
We called for a technician to come out and in the 30 minutes he was there the furnace ran fine (because it had been off for a few hours) and all the numbers he measured were within spec. He was all packed up and ready to leave and I asked him to wait just a few more minutes. Sure enough the furnace kicked off due to overcurrent. The bad bearing friction was causing heat to build (more electrical resistance) and the inducer motor to draw a few more amps every minute it ran until finally it was drawing too much and would trip the overcurrent sensor shutting the furnace down.
He replaced the inducer motor and it ran fine thereafter.
As to the flue and combustion air, there are most definitely codes that require the flue to be higher than the intake as well as requiring them both to be more than 36" above grade (to be above regular snow and bushes and such) when exiting a wall. In fact it is even in the installation booklets for the equipment… if your installer “reads”. The issue is that residential installations are not usually inspected… at least when a furnace is replaced. It might get caught when selling the house.
Another thing that installers don’t do right: the gas regulator
The regulator has a diaphragm and that can fail.
The guy that came to install a replacement regulator (because you can’t buy this in a big box store - so you have to hire someone who can get it from a contractor supply) put this in with the “top” pointing sideways. I told him that up needed to be up. He said no, this is a multipoise valve and will work in any orientation. I said yes, that is true, but the fine print says when vented to the outdoors. When it isn’t, that little nub (vent limiting device) screwed into the vent location has to be up to work correctly.
Recently, Indiana code no longer allows the use of the non-vented limiting device feature. Probably because “certified” guys like this were putting the regulators with the nub in the wrong orientation on a commerical building that is inspected.
Who knows how many houses have them in wrong. It is only right in my house because I, as someone who does HVAC design and knows some things, happened to get home before he was done doing it wrong.
Just did that when I went under the house. I definitely put it off far too long - it was GNARLY. Surprise, Rhea doesn’t like crawling under the house.
I’m getting some recommendations for local HVAC from coworkers and my neighbor, and getting ready to pay the fees involved in having this happen at the worst time while they’re very busy. Yaaay. Hopefully it’s an easy/cheap fix rather than a “turn off the gas & pay for a new one”.
I haven’t seen the back side of this unit since I’ve only crawled to the front a few times to change the filter, and I haven’t been to that side of the house.
And likely expensive…
There was no physical reason for them to do it, the original builder did it. There was plenty of wall space, no vegetation or protrusions to be avoided.
I discovered a few years ago that the builder neglected to put Tyvek wrap behind the siding on about 1/3 of the 2nd story exterior wall. It’s like they ran out and never came back with more. But they installed the siding over the bare OSB so there was knowledge and intent to ignore. It’s a condo, I only own the inside but I made sure to get that corrected by the management company. The OSB was covered with mold.
When the workman removed the OSB (4x8) it slipped from his hands and sheared off 2 gas meters below it. The gas was pouring out, super strong smell and loud hissing. Fire department and energy company arrived stat!
Happened to me, when I was very young.
Could be as simple as a run capacitor if it’s a forced air system. That’s a $20 part and about a 90 second job. Either that or the board could be fried.
It’s most likely 1 of those 2 things. But keep us up to date bc I love this stuff…. I do my own HVAC repairs. The only thing I don’t mess with is the freon, or whatever we are calling it now. Don’t have those tools and they are expensive.
Thankfully just $95 call charge - he spent 30 minutes under the house, baffled, did a check-up and a tune-up. Says the furnace itself is in good health. Yay for my house not being at risk of exploding after all.
It genuinely could be the system overheated over the air filter the one time, but it doesn’t explain why it farted out again the next day without tripping the breaker. It has, thankfully, behaved since. He gave me a referral to an electrician, which I’ll entertain after this winter storm fiasco.
So could be two things, it could be a faulty breaker, it does happen.
@joebcrafts made an excellent point up thread that I hadn’t thought of so next time it freaks out take note
For those who have em, start your snowblowers and or generators today and let em run a little. Makes starting them when you need them this weekend SOOOO much easier.
PSA as always, if you use a portable generator, remember to use it safely, exhaust and electricity can kill. If you backfeed into your panel DO NOT DO SO without a professionally installed interlock, backfeeding the grid can not only kill your generator, it can kill a lineman working on the “dead” line.
IIIII return with updates!
Sunday, heat went back out. I bought an oil filled space heater when this first happened, so I was cozy in my room, and the cats got snuggly.
Monday, Electrician came out and looked at my panel. Breaker tripping was determined to be unrelated, but he did find a loose wire that wasn’t actually tightened into its breaker, so he replaced that and checked the others. Then the guy who crawled under the house saw a flashing indicator that it as the pressure switch, and banged that until it came back on. Had heat overnight, was off again this morning when I woke up.
Today, HVAC comes back out with the diagnosis that the electrician passed along and replaced the pressure switch, which would either stick open or closed. Overall, about $300 in various parts, labor, service calls, and a day and a half off work, but I might actually have heat again, reliably, for the continued chaotic freezing event we have going on.
And if I don’t, I’m going to hurt someone.
Wow, that sounds cheap! Especially since multiple people were involved. Obvious that you’re not in my area!
Great that you got it taken care of (fingers crossed).