Air conditioning question

[cute fuzzy bunny]

Well, its not a refrigerant problem or anything non heat or overload related because on a cold start in the morning it kicks up and just runs.

I checked with the neighbors and they verified that this has the original 1987 thermostat in it. So given the options and my interests I ordered the $249 Totaline Wireless thermostat transmitter/receiver pair.

Big bennies to this are a) new technology and I know it works b) definitely has the 5 minute compressor restart lockout c) we can put the thermostat in the room we're in and have that room be the temp you set the thermo to.


We'll hit a 2-3 month period this summer (hell we should be in it already) when it'll be too warm outside to turn the a/c off even at night. We had a 3 week stretch last year where it barely dipped into the mid 80's at night. When that happens the upstairs in this house will be verrrry warm while the downstairs where the thermo is located will be nice and cool. Same problem with heat in the winter...it ends up very warm upstairs when all the cold air settles downstairs. We solved that last year by closing all the registers upstairs, but its kind of a pain in the butt to go around twice a day opening and closing old sticky registers.

First impressions are good ones. The receiver unit mounted in place of the old thermo and was no more or less problematic than a regular thermo replacement. The receiver take a pair of lithium AA cells and I fully expect it to eat a couple of these every month or so. Its programmable to house/unit codes so that in the unlikely event you have a neighbor with one, you can operate on different codes. The unit code allows you to get up to four of these and place them around the house...last one you push a button on becomes the 'active' unit and the one that sets the temp. The receiver has a little stand built in, and can be screwed or velcro'd to the wall.

Separately, looks like a replacement receiver or extra transmitter is about $130.

The unit can run heat pumps, two stage heating and cooling units, and so forth, so it should be compatible with any new replacement heating or air conditioning stuff I buy.

I'll probably just stick this to the 3rd floor wall upstairs in the atrium area outside the master bedroom that looks down on the other three bedrooms on the second story. Sort of a middling ground and I have a ceiling fan circulating air gently through that area. Then if I need the room we're in a bit more comfortable I can grab it and bring it there.

Another interesting feature is the 'auto fan' timer. You can set it to automatically run the fan for xx minutes at the start of every hour.

I'll update on how well this works for us. So far it beats installing extra heating or cooling units in various parts of the house.

 

[cute fuzzy bunny]

Okay, two weeks later I havent noticed any restart problems with the air conditioning, so the problem must have been that the old thermo wasnt giving it enough time between starts. It supposedly had the feature, but I guess something was busted or wore out in its 17 years of service.

We're very much liking the wireless thermo. I finally found the perfect place to leave it that results in the whole house being comfortable. I'm also using the 'auto fan' feature to turn the circulation fan on for 5 minutes at the top of the hour, every hour. That keeps us from getting warm or cool spots, which was a problem with Gabes room in both the old and new house.

So now that i've played with thermo location, I know the ideal spot to put the replacement permanent thermo when I get the system replaced in a year or so. Or I can just have them stick the receiver unit on the side of the new fan unit when they install it and forgo the cost of running new thermo wires and buying another unit.

So far no replacement batteries for 2 weeks, my one concern was that this might eat batteries. It does have a plug for a transformer, and i'm sure that the giant box o' transformers i have in the garage contains a compatible one.

 

[samclem]

Congrats, that was a relatively cheap fix and the info on where to put the thermostat was probably worth that price in itself. If the same thermostat send to your furnace (or are you on a heat pump?) then come winter time you'll have a chance to assure yourself that the thermostat is in the right place for heating or cooling.

I didn't know there were thermostats that would let you program the fan to come on for a prescribed amount of time on a set schedule. Nifty.

 

[cute fuzzy bunny]

I knew you could use an X10 type unit and have an X10 controller run it, or use PC based software...but I hadnt seen anything like this and was pleasantly surprised by it.

It'll help in the winter too. Where the thermo used to be is downstairs in a cold spot in the winter and we got way too much heat upstairs as a result. With the neutral location I've found, that shouldnt be a problem this winter.

After a week of 100+ weather, i'm already looking forward to the winter...

 

[Zipper]

You're apparently unfamiliar with californias central valley...

We're only about four feet from the surface of the sun here.

Radiant barriers lose effectiveness (supposedly) after 3-5 years due to dust collection.

I could increase the r-value in the attic, but we're getting hit in the upstairs on all the walls and you can just lay your hand a foot in front of them and feel the heat coming through.

The meat locker thing shouldnt be a huge problem...once the system kicks in the warm air from upstairs gets recirculated downstairs. The only real problem happens when the air stops moving, its staying nice and cool downstairs, and the heat builds up upstairs. A whole floor acts as a nice thermal insulating layer. Until you want to sleep up there.

Only trouble i'm having is finding one of these wireless dingy's available for sale locally. I'd like to take it back if I dont like it.

We have a 5 level backsplit and years ago I solved the hot bedroom freezing basement problem.

We have a laundry chute that goes from the top level to the bottom.

In the summer when the air kicks in I have a small concentrated direct flow fan that I aim up the chute.

It forces the cold basement air upward and the house maintains a constant temp throughout.

 

[cute fuzzy bunny]

Yep, innovative!

As I mentioned above, theres a spot in the house where the 3rd floor master bedroom closet shares a wall with the 3 story high 1st floor entryway. The two furthest points from each other in the house. A 12" square cut and a quiet 500-800cfm fan and we'd have full rotational air circulation.

Except the wife said I cant cut any more holes in walls or ceilings until I fix the one I cut in the garage ceiling in our old house. Which I still havent fixed yet. I havent clarified with her yet whether selling the house with or without the hole in the ceiling qualifies as having 'fixed' it.

The five minute auto-fan cycle pretty much accomplishes the same thing, since we've got dual air returns on the 1st and 3rd floors...for probably about the same cost as running a little fan all the time.

 

[cute fuzzy bunny]

Well its been almost a year since we bought this place, and its furnace replacement time.

To close out some of the above, the totaline wireless thermostat remains a two thumbs up item. The sending unit is still on its original set of batteries. Battery consumption was a basic concern in the purchase. Seems it'll run for at least 6-7 months on a set.

We take it upstairs to the bedroom before bed, and that room stays at the temps we like while the rest of the house cools down. The furnace only has to fire for a minute or two every now and then, by the thermostats orders, to keep that room comfortable. Whichever one of us gets up first takes it downstairs and drops it on the kitchen counter and the much cooler temps downstairs make the furnace fire off and warm the whole house up. Then it keeps the main living area temps at the same comfort zone.

Perfect for the ER or someone home all day that wants comfort, and an excellent solution for someone who has a poorly located thermostat or a particularly hot/cold room they spend a lot of time in.

 

[cute fuzzy bunny]

And now for the rest of the story, its time to replace the furnace.

Step one is that I've identified a couple of problems with the existing furnace. Its got a flakey flame sensor and I'm pretty sure a small crack in the heat exchanger. When it starts, it clicks the ignitor for about 3 minutes, then turns the burners on, then shuts them off a few seconds later, then relights them. When the blower goes on, the nice solid blue flames in the burners start to dance a little and get yellow edges. The former (I think) means the furnace cant detect the burner flame right away, so it douses the burners. The latter might be a crack in the exchanger that is blowing some vented air into the combustion chamber. No CO in the house so far.

I could call the home warranty company and they'd probably clean or replace the flame sensor and might replace the heat exchanger. Unlikely they'd swap the whole furnace and if they did, it'd be a piece of crap. Small chance I could get them to just cough up money for a replacement. Probably a month of phone calls to get them off the dime. Not sure thats worth the trouble...anyone else go through it? Its American Home Shield.

Past that, I've had some guys come out to give me quotes on replacements. So far they're split between guys that look everything over and then we stand in the driveway talking over some vague approximate numbers with a promise of a later full estimate and guys who show up with a briefcase full of laminated glossies designed to scare you about buying a furnace from anyone else, and offering tantalizing delights from their product offerings.

Looks like I may have a space problem in replacing the current unit and I may have to go with one of the smaller cabinet (34") Rheem units, but I havent researched any other low profile units.

Current furnace is an 18 year old single stage 100,000btu carrier that used to be a 70% efficient model, coupled with a single stage 4 ton 9 seer a/c unit. The heater is a bit oversized, I might get away with a 75000 and definitely with a 95000 btu unit.

Anyone replace anything like that recently? What'd you pick and why? What was the total cost?

I'd try a DIY replacement, but california code updates are extensive. I'd have to run a new gas line and flue, and the ducts have to be sealed to 15% loss or less and program tested by a state approved company before they'll issue a permit to replace.

 

[Walt34]

Back in the early '70s I worked on heating & A/C. The flames dancing when the blower starts tell you that the heat exchanger is definitely cracked. That is a dangerous condition - that's one way carbon monoxide gets in the house. If you're not getting any yet, you will. Keep an eye on your CO detector!

The last time we replaced a furnace (natural gas) about 7-8 years ago we ended up buying the exact same size. During cold spell (for us -5 F is as cold as it ever gets) the furnace ran constantly except for about 5-10 minutes then come back on. That's about where you want to be so you won't be chilled in even the coldest weather for your area.

We bought an 80% efficient model vs. the 90% efficient because the cost difference wouldn't make up the difference in efficiency. Additionally, the 90% one had to have specialized service annually, the 80% I just kept the filter clean and looked at it once in a while.

The warranty company may replace the furnace. Things may certainly have changed but when I was working on furnaces a broken heat exchanger meant scrap the furnace because the cost with labor was almost the same as a new furnace. The worst they can do is say "no". Or you could offer to pay the difference to get a new furnace.

 

[cute fuzzy bunny]

Yeah, I put a call into the home warranty company. Its worth the $55 for the service call just to see what they'll say.

Plus I seem to have some spare time on my hands to be annoying.

 

[travelover]

...............Plus I seem to have some spare time on my hands to be annoying.

If we don't hear from you we'll know the CO leak got ya.

 

[cute fuzzy bunny]

Some might say that it already did...

Four detectors in the house. I think its just blowing OUT through the crack right now, not drawing in. Upflow furnace. I dont think its a big crack either, its just making the blue flame a little yellow and making it dance a little at the edges.

 

[ERD50]

100,000 BTU sounds way over-sized. We have a large house in Northern IL, and a 125,000 BTU furnace (90% eff) does not run full-time in even the coldest weather each year (typically a few -10 to -15 days, occasionally lower). Average insulation.

Like Walt34 says, that is the optimum - just enough to cover the worst cold spell. Cycling on for just a few minutes is inefficient.

-ERD50

 

[cute fuzzy bunny]

Dang thing just croaked on me. Spark only, no pilot. Guess what i'll be doing for the next couple of hours...

Good thing I put that call into the home warranty company. Looks like my optional replacement situation just changed.

 

[F M All]

I can't stand the suspense any longer ................ what happenned next?

 

[cute fuzzy bunny]

Well finally someone expresses concern!

I ended up taking the whole thing apart, cleaning it, applying some percussive maintenance and putting it all back together again and all was well. My initial problem was that either I wasnt getting any gas to the pilot or the spark wasnt hitting it. Not sure if the gas valve was stuck, the sparker wasnt adjusted right or some sensor was dirty or out of whack.

It ran well for another couple of weeks, although I hoped my 'maintenance' might have hastened its total demise. No such luck. But I'd have enough of the old clunker.

I then went through what I learned was an enormously bizarre process of trying to buy a new furnace and air conditioner and have it installed. I believe most HVAC companies are right on par with car dealers. They seemed to be divided roughly into three camps: (1)the guys who werent going to do anything except give me droning sales pitches until I was ready to pay them to do whatever it was they were going to do once I paid them, whatever that was, (2) the guys who were high volume mills with a slick sales pitch and cheap guys who would slap the system in, and (3) some guy and his brother(s) who took some classes and started a business doing it.

I didnt get anywhere with category 1 because I'm not doing business with someone until they tell me what they're actually going to do and how they're going to do it. These guys either havent figured out that you have to invest in the sales process and occasionally not get the business.

I wasnt comfortable with category 3 types because if the guy gets sick and something goes wrong with the system, I'm screwed.

So I went with a #2 company. Literally. They did at least 15 things completely wrong, several of them safety related. I ended up fixing a couple of things and showing them how to hook up one piece of the equipment that they'd obviously never seen before and werent smart enough to figure out. There are at least 3 things that I hate about the job that cant be fixed without tearing it all out and starting over, and i'm still duking it out with the salesman over those.

But its 95% right, looks a bit ugly because they gave me an ARI matched coil thats the wrong size, didnt quite fit...yet is slightly more efficient than the one thats the right size.

So now we've got a Carrier Infinity two stage furnace and variable speed blower with a 16 seer two stage air conditioner and a Trane Cleaneffects electronic air cleaner. We run the unit on low fan all the time drawing about 95 watts of power including the air cleaner. The cleaner allegedly removes everything down to the size of bacteria, and since installing it my wifes asthma has improved as have my allergies. I use the Infinity control to rev up the fan periodically to keep the air moving.

The two stage heating uses an adjustable gas jet to produce either a medium or full flame, and the variable speed fan adjusts from 500-1600cfm of air flow, starting gently and then building. If the low flame doesnt warm the house quickly enough or the control detects a large variance in temperature (like someone opened a door for a while), it kicks in the full jets. The two stage cooling uses a reciprocating compressor that runs one way to produce about 50% of its cooling ability (at about 50% of the cost) and then spins backwards to produce the full 100%.

So what you end up with is a system that runs longer producing a bit less heat or cold, with more gentle blower action, yet is very capable in high heat and cold situations, and excellent circulation and balancing of temps throughout the house...for a lower electric and gas bill than the 15 year old system we used to have that would blast out ridiculous amounts of very hot or cold air spastically throughout the day. It also solves our problems of having the upstairs too warm year round.

I'm guessing it'll be even cheaper this summer when its 110 out and we're running at 16 seer/12.5eer vs the old systems 8seer outside unit that was 1/3 buried in dirt when we bought the house...

Glad you asked?

 

[samclem]

CFB,

- Hey, you were a naysayer on centrally installed air cleaners. What changed your mind (or was it simply DW's wish) to buy the air cleaner? I take it you believe that the relief in allergy symptoms is more than the placebo or Hawthorne effect, right?

- Variable burners/fans, etc. I've got a two stage setup-not as deluxe as yours, but the same principle. I've had folks tell me not to use a setback thermostat at night, because it will actually increase my gas bill. There reasoning: In the AM, when the thermostat re-sets to a higher temp, the furnace will also go to high burner (since it sees that you are several degrees off the desired setpoint, which wouldn't normally happen unless the low burner were unable to keep up with heating requirements. In high burner the furnace is (somewhat ) less efficient. So, according to these wags, you shouldn't use the setback because it forces the furnace to be less efficient for a time.
I have nothing to refute this with, other than a gut feeling that leaving the house 5+ degrees cooler for 6+ hours probably saves more gas than is used up by the slightly less efficient burner mode in the fairly short time that the thing is playing catchup.

BTW, my experience with HVAC contractors was also poor. None of them wanted/knew how to do a proper heat load calculation. I did it myself online, and installed a system approx 50-60% of the size the contractors wanted to install. We've set some record cold spells and the system has never had any trouble keeping up. If I'd not done my own research I would have ended up with an overly expensive, less efficient furnace and an AC system that left too much humidity in the house (due to an excessive fan size).

 

[jazz4cash]

Data! I need data! [-]Watts [/-] BTUs Tonnes AFUE (or whatever its called)

 

[jazz4cash]

CFB,

-
BTW, my experience with HVAC contractors was also poor. None of them wanted/knew how to do a proper heat load calculation. I did it myself online,.................. .

do you happen to have a link to an online heat load calculator?

 

[samclem]

The "Gold Standard" is a formal "Manual J" calculation by a certified contractor. You can buy the book and software to do it yourself for a hundred bucks or so. Maybe you can even find a contractor who will do it right--I couldn't.

Here is the online calculator I used (no guarantees--but it worked for me):

MrHVAC.com Heat Gain and Loss Short Form Load Calculator

 

[cute fuzzy bunny]

You pretty much found the source of the impetus for the air cleaner install. My issues with air cleaners are that they can remove what they take in, but much of what can cause respiratory problems is direct source (having a dog sleeping next to your face or a cat on top of your head) or large particles that settle on the floor, couch, bed, etc. Get a bright light point it at your choice of furniture or flooring and give it a whap. Heck, go into your closet and give your clothes a good shake.

An air cleaner just wont help with that. The biggest benefits are keeping the critters and other allergens out of the house as much as possible, cleaning as much as possible, and even then I think you're just mitigating the potential problems somewhat.

As far as the usual allergen reduction pleated filters, I got fairly unanimous feedback from HVAC pro's in person and online: they get to do a lot of repairs as a result of their use straining system fans through excessive static pressure and damaged coils/heat exchangers from reduced air flow. Plus those old systems dont run often enough except during the hottest and coldest days of the year to do much air filtration.

So, per the wife, when she's sitting in a room with an air purifier, it makes her feel better. I clean their filters, so I know they arent really catching that much. The prefilter takes a nice thin layer of fuzzy dust over a months use and I generally get 3 years out of a hepa filter before the air flow starts dropping.

Since our three big room air purifiers were nearing the end of their service lives, I had the choice of peeling off a thousand bucks for three new ones, going through a couple of hundred bucks of filters and maintenance on them per year, and having what I know is a practically useless "solution". Oh, and they cost me about $250 a year in electricity to run.

Or, since we had an aging furnace, I figured I'd try drinking the HVAC marketing koolaid and try one of these centrally mounted units coupled with the low flow constant on variable fan furnace. Generally the cost was about $1500 for this combo over a non variable fan and no air cleaner. The electricity costs to run that fan and purifier for a full year at my rates is about $130. I remove and vacuum, wash or blow out the prefilter and collection cells and those should last between 5 and 10 years. No filter costs for the furnace or the air purifiers.

I'm getting another small benefit in equipment lifespan by virtue of having the filter sitting directly under the furnace rather than at the return grills inside the house. Theres no such thing as a perfectly sealed duct (well, the aeroseal guys will give me some trouble about that) so those returns are pulling at least a small portion of their air from the attic or crawlspace. Plus the dust and crud thats in that air, which in my old system ended up catching on what was the best filter in the house: the wet a/c coil, reducing its flow and efficiency and requiring cleaning.

So economically I come out way ahead. The wifes happy. It actually seems to be doing something useful for us where the old room units werent doing much of anything other than blowing a little air around. Its good for the equipment.

This system is a 90k btu furnace, four ton, 80% afue. I didnt go for the higher efficiency gas burner for a bunch of reasons. Our winters are so mild I'd get about a $30-40 savings (max) per year...it'd take me ten years to get something approaching a payback for a 92% AFUE. The >80% units use a PVC vent instead of the old 4-5" duct and I had nowhere to vent it since the unit is in the garage with two floors overhead, a very visible side of the house on one side and a lot of expensive landscaping on the other side, both of those with large roof overhangs. So I'd have had to have a black pipe sticking 3' out of one of those sides for venting. Oh, and the 90+ furnaces have a secondary heat exchanger and a lot more junk in them that can break, and theres a lot of anecdotal evidence in the HVAC community that they're not as reliable in the long run and need more maintenance.

Sam, as far as your setback question...I dont think thats the case. A furnace uses a certain number of therms of gas to create a certain number of btus of heat to create a certain amount of degrees of change. Whether its using a full flame for an hour or the half flame for two hours, its the same. The only difference is run time and comfort level. You'll get some additional duct heating/cooling loss in the longer running first stage, since the ducts are r-6 or at best r-8. So its plausible that setting back not only saves you some energy at night, running it up in the second stage in the morning might be MORE efficient. If your ducts were 100% efficient with no loss, it'd probably be a toss-up.

I couldnt find a guy to do a manual J either. Manual J discussions tend to run like our annuity conversations and there is merit on both sides. A full manual J takes about 3-4 hours to run, and in general for most ordinary homes, might change a seasoned installers opinion by a half ton or so. Where you get into strange stuff is older homes that lack insulation, lots windows, drafty homes, funny basements with odd ventilation, homes with lots of vaulted ceilings, etc. Then some environmental aspects outside the home can also make a lot of effect like lots of trees and shrubs, adding solar screens to the windows, storm windows, yada yada yada.

I had one guy measure all the rooms with a laser tape (which I immediately wanted) and do a 20 minute back of the envelope calc and he came up with a 3.5ish number, but said the 4 ton would be recommended for the higher air flow in the summer when the heats blazing. Four other guys came back with 4 ton. One guy suggested a 5 ton, but I know my ducts wouldnt take that much air flow...the house would sound like the boston pops warming up for a concert when the fan was running on high.

The bottom line for the 3-4 people still eating popcorn and reading this is that an oversized system will waste a little money up front for higher equipment costs, run short run times, which is inefficient, will blast out lots of very hot and cold air, which is uncomfortable, and not run often enough to balance air temps. A system thats too small will be unable to keep up on the hottest and coldest days, but up to a point a system thats slightly too small is way better than one thats slightly too big.

I got into a stalemate with two companies. They had their guy come out and eat up 90 minutes of my time telling me how good their company was without disclosing what equipment they'd use or recommend ("it depends!"), sizing or approximate cost. I told them 4-5 times that they were sitting there because I'd already vetted them and come up with only people that were recommended and didnt seem to have a lot of problems. Which didnt stop their sales pitch. We then got into a race condition after that where they wouldnt cough up any details until I was willing to give them the business. No way.

Interesting reading some of the hvac web sites. These folks seem to have a strong disdain for the homeowner and anyone wanting to do any maintenance and repair on the unit themselves - quite a difference from our own general philosophy here. They want the hvac stuff to be a mysterious black box that only a pro touches. They often compare their learned skills to be the equivalent of an MD and worthy of the same price/hour. In short, they remind me of financial planners. But of course, not the really good ones like we have here

I think if I were going to do it again, I'd skip the slick willies and the large mill shops and just find a company with the word "sheet metal" in their name (there were plenty) or the guy and his two brothers, do a quickie load calc on my own, tell them what I'd like them to install, and let them do the mechanical install. Make sure I get a FACTORY transferable parts and labor warranty.

I found some anecdotal operational and reliability data that backed up what CR came up with...that carrier/bryant/payne and trane/american standard might make slightly better gear and goodman/amana/janitrol was a little behind the pack. But a good system badly installed wont do as well as a slightly below average system installed well.

Based on product cost and availability, plus long warranty I might install one of the goodman variable two stage units with a higher seer a/c than i got. The equipment is enough cheaper that I could get that for less than I paid for this. Everyone fixes goodman, there are plenty of places both B&M and online to get parts and whole units, and they've got one of the longest warranties in the business.

My original intent was to go that route, but I had the damnedest time getting someone to give me a quote on the product. Everyone listed goodman, but bad mouthed the product and downplayed the cost savings on their way to quoting me a carrier or trane system. I think the installer industry in general hates goodman for the way they sell to everyone and their price policies...doesnt make for a happy exclusive marketing arrangement for the retailer/installer.

At the end of it, I was just tired of the whole thing, didnt want to fight city hall to save $500, and figured it might be money well spent to put in one of the major brand names and make it a minor benefit to a buyer on resale.

You may now return to your regularly scheduled program, War and Peace...