Air conditioning question

[cute fuzzy bunny]

Quote:

Originally Posted by cute fuzzy bunny I put the kill-a-watt on our unit with just the fan running. I forget what the reading was but I remember the expletives I spit out...it was pretty high. 150-180 watts...something like that.

Wow was that freaking wrong. Just checked it again and its 700 watts. Our old one (only 8 years old) was 533 running just the fan.

It might be time for a new furnace and air conditioner a little sooner than I thought...

[HFWR]

When I replaced my AC unit, anything above a 12 SEER had a two-stage fan. However, the cost went from $3k-ish to >$7k...

A problem I have is, after the system has been off for a time, then kicks on, the first several seconds consists of all the hot air (duct work in attic) being cleared from the ducts, sometimes RAISING the temp in the house a degree or two...

If I wasn't so lazy, the fan on my current furnace (which serves as air handler for both heat and AC) has a half speed tap. With a fairly simple solenoid switch and some minor circuitry, I could run the fan at half-speed while the compressor is off, recirculating the air in the ductwork, and preventing excessive heat build-up, and saving at least a few bucks in electricity over leaving the fan running at full speed all the time...

[cute fuzzy bunny]

Wouldnt you actually be making it worse? Right now you're getting an insulative heat leak into the ducts in the attic that probably hits a certain point and remains there. If you ran air through it all the time, wouldnt you suffer a continuous insulative heat gain spread across all the air in the house as its run through?

[HFWR]

Beats the heck outta me... I just figured keeping the air moving would limit the temp swings.

[cute fuzzy bunny]

It'd keep the temps more regulated and consistent...

[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]

Quote:

Originally Posted by cute fuzzy bunny 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]

Quote:

Originally Posted by cute fuzzy bunny ...............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?