I have a 9 day old new Bryant furnace. It is the mid-grade 95% eff. furnace. The salesman told me because of the size of my house – 3200 sq. ft. I would need a 95,000 BTU unit. I was also told it would be quieter than my 18 year old Payne. So I need to know if I should call the intaller back for some issues or am I just being too picky?
1. It is not quieter. If anything it is louder especially on start-up. The ignition process – if that is what I hear before the blower comes on – rattles the duct work. The blower is about the same db level as the old model.
2. It starts up and runs for 10 minutes and shuts off for ten minutes like clock work. On/Off no matter what the set temp is in the house or the outside temp. The outside temp has been 26(N) and @ 35(D). I am on a prog thermostat so I have the temp at night set at 66 and during the day 68. Not much of a swing. Regardless of outside temps or inside setting the furnace is so precise you can set you watch to it – on for 10 off for 10 and back on.
Should I be concerned or is the way of the new products?
Thanks, Mike
Replies
I ain't a furnace expert, but I'd have the same reaction ... something isn't right. Maybe there is a sensor or device out of adjustment. I'd look up your model on line for some troubleshooting hints and/or maybe call a tech up at the factory. Know as much as possible before calling the contractor back.
Personally, I get a little uncomfortable around contractors who may have a tendency to tell you it's 'normal' when it isn't. No offense to contractors, but I do tend to be just a little cautious until they make me comfortable with service and logic. If I feel I'm getting the brush off because they are just too lazy to address a situation, I get upset.
As for quiet ... the nature of a forced draft combustion system will naturally have a tendency to be noisier, I think ... it's got a fairly high speed fan in it. I have a water heater that is the same way. Sounds like an [old] car starting/revving up. Not sure why anyone might say it would be quieter ... WHY? Fundamentally, it's got more fans; unless you had something unique about your old system, there should be little that makes the new one quieter (they haven't really been designing quieter supply fans).
If your ducts literally 'rattle', maybe it's time for a little work? Some duct sealant and then maybe some sound absorbing material around the first few feet. You could put a sound attenuator in it, but that is extreme for residential and usually isn't required w/ the low duct pressures and [relatively] 'quiet' :) operation.
Furnace size sounds right ... depending on how old the house is. Newer houses may not be near that much. Again, many contractors will rule-of-thumb the furnace size w/out calc'ing a load. You are in a cold climate, though ... so the size isn't particularly alarming to me. You also have the limitations of the available equipment sizes (if the next smaller size is e.g. 65,000 and your load is 70,000, then there is a tendency to CYI and go with what might be an oversize unit).
The entire story: I asked on this web site if I should have my furnace - the old Payne model - checked from time-to-time. The answer was a resounding 'yes'! One forum author suggested a local Heating/Cooling outfit Schaafsma. He concluded they are certified in not only the inspection process but in the ability to adjust flow/heat etc. with precision. I called.When the inspector did his thing at my house he called me on my cell and told me that he had shut-off the gas supply and pulled the switch on the old furnace because of a secondary heat exchanger problem - it was rusted out to a point where its integrity was lost.That night the salesman arrived and did a total walk through the house - checked insulation in the attic, the state of the windows, the door security and many other items. He then estimated the cost of a new Bryant - that is all they sell - and its size. It was installed 3 days later.I am far from a heating/cooling expert. When he - the salesman - was there he indicated the new Bryant would be considerably quieter than the Payne and more energy eff.. My old Payne was 90% eff. This new model is 95%.They told me that after installation - perhaps 4 weeks after - I would receive a call from a service tech who would make an appointment to review the furnace with me, check its operation and adjust of necessary.Should I wait until then? Advice is always appreciated.Mike
I think when you asked about the quality of the Bryant product, a large part of my response was: "the most important feature is the proper installation", or something to that effect. As you have learned, that feature isn't offered by all the hacks aout there.
By all means, call the installer back until you are satisfied. Do not give up until you are satisfied and don't let them off the hook. And do not wait until they get to the follow up. Have them re-schedule a "final" two weeks after you have had no problems.
The cycling is a set-up issue. The installer did not set/set-up the thermostat correctly, or did not provide the correct thermostat. Have them come back and set it up right.
The noise issue should be easily addressable by the installer (and was most likely caused by the installation) as well.
Good luck.
Edited 11/24/2008 2:19 pm by Tim
Could the on off cycling be short cycling from over-firing, or perhaps obstructed air flow?
"Ask not what the world needs. Ask what makes you come alive... then go do it. Because what the world needs is people who have come alive."
Howard Thurman
Yes, absolutely. Over-firing or the unit being oversized for the load is classic reason for a system short-cycling. The thermostat my simply be limiting the unit to 6 cph (cycles per hour, which I think is a default for most new programmable t-stats) which is exactly what it is supposed to do. It could be something as simple as supply air being directed at or in the general direction of the thermostat, where it was not previously. Or it was but the new unit moves more air.
I don't know how obstructed air flow would affect the unit cycling, at least not in the way described. I would expect a reduced/obstructed airflow to cause the unit to be less effective at meeting the thermostat setpoint, resulting in longer cycle times, not shorter.
Not knowing the specifics and I made the assumption (I do know better than to do so, but...) that the OP has not changed the thermostat, its setting(s) or location and also that the excessive cycling did not occur with the previous unit, all other factors being unchanged. These need to be verified by the OP.
What we don't know: output of the previous unit, air flow of the previous unit, any known problems related to air distribution, previous unit cycle times, or any other changes made during the swap that could affect unit cycle time.
"What we don't know: output of the previous unit, air flow of the previous unit, any known problems related to air distribution, previous unit cycle times, or any other changes made during the swap that could affect unit cycle time."I'm not a heating guy so bear with me:Old unit was a 90% efficient Payne rated at 85,000 BTU. There were no heating problems - no cold rooms or excessive heat build up in the summer time (central air). There were no consumer complaints about air distribution. Previous unit had no cycle times that were time related. No other changes made during the swap - duct work is intact and has been in the house as is for @ 30 years.Mike
Hard to say for sure. You can barely hear our HE furnace when it starts up, but it's a two-stage unit so it starts up quiet and only puts the fan on full if it runs longer than a certain time. When the fan's on full, though, you can for sure hear the air whistling through the registers, just like our old furnace.
We have had some trouble with rattles and a whistle in ours, but I tracked down most of those problems.
The 10 minutes on/10 minutes off sounds suspicious. And the installer should be able to do something about the rattles.
Do keep in mind that every piece of this type of equipment has its own unique noises, and often you've gotten used to the old stuff and "tune it out", but not the new equipment, even though it's quieter.
Thanks - the 10 minute routine must have something to do with an internal clock? Anyway, I have called and left a message. No response yet. When I do hear from them - or they come to my house to inspect I will let all of you know what was said /done and evaluate from there? Thanks, Mike
when i first put in our unit,i had lots of cycling. heres what was happening,i had put in a honeywell thermastat that would hold to 1 degree. sounds great.
so i set it at 70,temp goes to 69,furnace fires and the chamber starts heating up,the blower kicks on and boom i n 1 minute the thermasat says 70, time ti shut off. off goes the flame,fan cools the chamber down,shuts off. in about 4-5 minutes thermastat hits 69 and here we go again.
solution, i put in a old honeywell round thermastat that swings about 3 degrees,kicks on at 69 shuts off at 72. everyhing is great.
as far as noise,i just worked on a furnace this morning that the exhaust vent was much nosier than the blower fan. do you here yours a s soon as the burners ignite or when it starts blowing air.
i gotta say i would be a little leary of the story you got to begin with . if you had a 90% furnace i would guess no older than 20 yrs,thas pretty early for chambers to wrought out.if a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
The stat should have a deadband/throttling range adjustment to go beyond 1 deg. That's a stretch and hard on your furnace to cycle that much. 4-6 deg span would be better.
Now that I think about it ... I like my radiant floor because the pump cycling doesn't always kick on the water heater ... so it doesn't cycle much, really. I had an HVAC guy said he didn't like the water heater tank because it would cycle on anytime my stat called for heat ... but that isn't the case at all. He preferred an instantaneous water heater which WILL cycle every time the pump cycles on.
HUHHHHHH?
We usually aim for 1/2 degree either side of setpoint.
You don't tell office workers that 6 is normall? That's getting close to what some leases allow for total allowable temp range.
Sure I do ... my employer mandates a comfort range of 68 in winter to 78 in summer. In between it floats. 2-4 deg deadband I think is a common 'standard' (thinking the old Honeywell pneumatic controls days).
6 degrees is "getting close to the allowable temperature range" ... yes ... exactly. Kind of what I thought I was saying. Kicks it on at 68 and off at 74 to let it float down. Maybe a BIT much, but not necessarily out of reason, do you think? I think the 4 Fdeg is kind of standard though ... on 68, off 72 and then cooling on 74, off 78. One degree, in my book is too tight. Although I've worked on some research facilities that require a tighter deadband ... but that is a different story and system all together.
Nope. 1 degree should be easily attainable. No complaints from customers usually dictates 1 degree swing.
Oh, I don't argue comfort and that it can be attained. Just that it is hard on equipment and overall efficiency ... equipment is best run for as long as possible. On/off cycling isn't good. 1 deg IMO is not good and humans usually can't tell a temp swing of less than 3 deg, so really a 4 deg swing is doable, normal, and generally comfortable.
1 degree isn't hard on the equipment at all if you're talking a large commercial setup with pneumatic controls. After all, you're just switching dampers on and off. Harder on a residential setup, probably hardest on oil.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
I thought that's exactly what I said ... but I guess not exactly. Commercial systems are 'easy' to do ... you just don't want to control it that tight. Hard on a small residential system that kicks on/off a lot ... right. I must not be writing clearly late at night.
You're both right and you're both wrong. The details of the system and how it is intended to operate make the difference. For a on/off (standard residential, single stage, multi-speed FA sys) control scheme, a deadband of less than 2 or 3 degrees is foolish. For a VAV (residential 2-stg with a variable speed FA sys) 1 degree is not bad and easily workable without undue cycling and stress on the system. IMPO, a deadband of less than 2 degrees in any application is inappropriate, but that's an opinion. Other factors contribute, the stability of the structure (mass, drafts) and one of the most often poorly executed "features of any system, location of the thermostat.
Whether the controls on a commercial system are electronic or pneumatic is immaterial. The manner in which the system modulates and what is controlled does. Commercial systems, BTW, do not modulate by "switching dampers on and off", at least not those that work properly.
Budget: I can hear mine fire-up. It makes a noise like a jet engine starting - but much quieter. You can hear the fire start. Soon after the blower comes on and lasts about 8 minutes. 10 minutes later the whole process again.The Payne furnace had a problem. A failure that resulted in a modification for free. Apparently the Co. would replace the secondary exchanger for free or give me $1,500.00 towards a new furnace. I opted for new. So I paid a total of $2200.00 for the new Bryant including install.My thermostat is @ 5 years old. It is programmable. Frankly, because I am so seldom there I simply keep it at 67 and dress warm when home. Is this perhaps causing part of the problem.Mike
why don't you pull up a chair ,get a book and watch your thermastat.
you have it set at 67. see when it kicks on.make a note,see when it kicks off. how much spread does it have? the tighter the spread the more it's going to cycle,but the cycles will be short.
heres something i don't think has been mentioned, w is your thermastat location. any chance the new one is blowing a little harder and directly hitting the stat? that will really mess with it.
the sequnce you should here is,click,stat calls for heat
you should here a fan kick on,it will run for a few seconds,this is the vent fan.
then you will here the burners light,they will probably burn for 45-120 seconds then the blower fan will come on,
then stat is satisfied and shuts it down,with the fan cooling the chamber for maybe 60-140 seconds.
i had a thermastat that the sun would hit in the afternoon,it went nuts with heat or cool.
what a deal on the old furnace,1500.!!!
if a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
Edited 11/25/2008 7:09 pm by alwaysoverbudget
Electronic programmable thermostats have a "cycles per hour" setting that is intended to limit excessive cycle from an oversized unit and/or poor systems layout and/or thermostat location. IF the system is oversized or the thermostat is located in an are that it is satisfied very quickly, but the heating load is not being met, it will cycle excessively. The unit itself has no clock and other than some pre-programmed (and unchangeable) sequencing in the firing logic built-into the fan control board, has no idea how long it is firing or not firing. There is an exception for a two-stage furnace operating with a single-stage thermostat. It will heat at low fire for a set time before initiating high fire. This, too, is pre-programmed and fixed logic of the fan control board.
Cant speak on the noise issue but I rememeber from my HVAC supply house days that more efficient furnaces run more often and for shorter durations. It has something to do with the temperature of the air coming out.
A more efficient furnace will blow cooler (to the touch) air than a 70%er. Because of that it needs to run more often but at the lower temp, it s more efficient.
Family.....They're always there when they need you.
No, the most efficient setup is where the furnace runs continuously. When it's constantly cycling it doesn't get a chance to run at optimal conditions for very long.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
I agree with you on this one. Cycling is a result of inexact equipment sizing, limited modulation and simplistic controls. With the exception of modulating, condensing boilers, gas fired appliances are the most efficient at their maximum capacity with large temperature differences. Addionally, the start-up and shut down sequences, particularly the start-up are fuel wasting processes.
The thermostat is Honeywell 33. It word fine on the old Payne without the cycling problem. It is the DR area of the house - frankly right in the middle of the first floor area. No sunlight can hit the thermostat so that is not an issue. I took your suggestion to heart. I got John Grissom's 'The Appeal' and watched. I set the thermostat to 67 degrees. The furnace did it regular cycling - 10 min on and 10 min off. The thermostat temp never changed. It did not go up a degree or down a degree. Since I am not a physics major that seen to suggest one of two things:1. The cycle of the furnace is so quick at 10/10 that the temp in the house never changes OR2. The themostat temp difference is perhaps a 1/2 degree +/- so it never shows on the temp scale since it registers only whole degree increments? Now what?Mike
Something is clearly missing here: Presumably the outside temp is varying in some reasonably random fashion from day to day, and is going up during the day and down during the night. If the furnace were firing exactly 10 minutes on/10 minutes off the inside temp would not remain at all constant.I wonder if it's the fan that's cycling 10 on/10 off, for some obscure reason. Or perhaps the furnace is coming on, erroring off somehow, and turning itself off for 10 minutes to reset.There should be a LED/LCD error code display on the control board for the furnace. Check that (there should be a window to let you see it with the inner cover still in place) and make sure it's blank or zero. If it's showing a code, look that up in the book your installer should have left with you.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
I am not at home right now - hate the idea that work gets in the way of home projects. I will check tonight. This display should be on the front panel? If no there is it perhaps inside of the front cover panel? Can I open that without damage? Thanks, Mike
Remove the outer front cover -- should just snap off, or maybe you have to lift it up off of hooks. Should be able to see the error code readout through a window in the inner cover once that's done.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
And, FWIW, our 2-stage HE furnace maintains the inside temp (as read on the thermostat) within a degree. I'd guess it runs about 10 on/15 off at 20F, and maybe 15 on/10 off at 0F. It switches to high output after 8-12 minutes.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
"It starts up and runs for 10 minutes and shuts off for ten minutes like clock work. On/Off no matter what the set temp is in the house or the outside temp"Does it really cycle every 10 minutes no matter what temp is set on the thermostat? Have you tried setting it at 6 degrees above and below room temp, say, 60, then observing the cycles. Next set it at say, 72 and observe. Let us know the results. From what you've posted, the furnace would still cycle every 10 minutes. If this is the case, someone here will give you a good answer, and it has nothing to do with normal high efficiency furnace operation or sunlight on the thermostat.
"Does it really cycle every 10 minutes no matter what temp is set on the thermostat? Have you tried setting it at 6 degrees above and below room temp, say, 60, then observing the cycles. Next set it at say, 72 and observe."I will try that experiment tonight. That is an excellent suggestion and I'm almost embarassed I did not try it before - more to come after Turkey Day.The outside ambient air temp does fluctuate during a 24 hour period. 24 low last night and 38 high today.Thanks everyone: I actually enjoy this stuff even though I am a novice.Mike
The thermostat is Honeywell 33. It word fine on the old Payne without the cycling problem.
The thermostat may be the problem. I just had a new system installed with a similar gas furnace - mine's a Carrier.
They replaced my thermostat with a new one. The installer told me the HP/furnace would cycle improperly w/o the new thermostat and was critical for proper operation. The blower is variable speed. The new thermo is designed to keep the fan running as slow as possible with a minimum of cycling and everything speeds up slightly as more heat is called for. What may be happening in your situation is the thermostat is telling the fan to run at high speed when it should be running at low speed.
http://www.quittintime.com/ View Image
Edited 11/26/2008 4:43 pm ET by seeyou
> The new thermo is designed to keep the fan running as slow as possible with a minimum of cycling and everything speeds up slightly as more heat is called for.I doubt it. Unless you buy a really fancy unit the thermostat doesn't control fan speed -- even the better digital units just wiggle the wires like an old Honeywell Round.All of the "smarts" are in the furnace, not in the thermostat. The furnace decides when to call for higher heat, when to increase fan speed, eg.(Irritating as heck to us computer types -- you have a computer in the thermostat, one in the furnace, one in the zone controller, and one in the humidifier, and they all talk to each other via a protocol more primitive than Morse code.)
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
If he has an infinnity control, it ain't your grandma's stat.
I have an Infinity control.http://www.quittintime.com/ View Image
The old style T stats had inside them a thing called an "anticipator". It was little dial thing about the size of a dime inside the T stat. It was adjustable and you needed an amprobe to find the right readings. You then applied those readings to the anticipator dial.
Basically what happens when you set the t stat at 70F and as the heat starts to rise, the anticipator anticipates in adavance of the 70 degrees and shuts off the furnace. Even though the furnace shuts off prior to reaching 70 degrees there is still an overshoot of 70 degrees though much less if there wasn't an anticipator . The anticipator also works in reverse in that it anticipates in advance that the room is cooling and need to turn the furnace on before it actually needs to.
If you had a furnace that didn't anticipate anything your furnace would go an an off hundreds of times in a day. The closer the on and off times are the more times the furnace needs to work. That is the reason why people leave their fan on all the time to help moderate the temp and to stop stratification of the hot and cold air.I'm sure the digital T stats have an electronic version of the anticipator built in and is probably adjustable.
Your cooking oven doesn't have an anticipator so when you first turn on your oven to 350F the temp will over shoot to maybe 450F then drop down to maybe 250F then kick on and over shoot to maybe 400F and drop down to 300F. Over several cycles of on and off the cold oven heats up so that the oven cycles at about 325F and 375F which gives you your wanted "average" temperature of 350F.
You can now tell your wife that when the recipe says to preheat the oven at 350F, wait for several cycles.
roger
roger
All of the "smarts" are in the furnace, not in the thermostat. The furnace decides when to call for higher heat, when to increase fan speed, eg.
There is truth to that, but something like a Honeywell VisionPro IAQ stat does a whole lot... and it communicates with the interface module over 3 wires. That one stat will control a whole boatload of stuff through a single touchscreen interface.
The stat will call for multi stage heat (or cooling) and the equipment responds.
Blower timers are on the furnace board, and the programming for the variable speed drive motors is in the motor housing controller.
The IAQ model is probably similar to the Infinity control.
The Carrier "thermidistat" protocol (which I assume is what the Infinity controller uses) employs 6 wires minimum, and up to 11. The main differences between it and a regular thermostat (aside from programmability, remote control capabilities, etc) are:* Two stage heating
* Two stage cooling
* Dehumidify connection
* Humidifier connection
* Outdoor temperature connectionIt wires like a conventional thermostat.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
The Honeywell IAQ will do all that with just 3 wires from the thermostat location to the interface control module.
Great for those times when there are just 4 wires from the stat location to the equipment location.
There can be plenty of wires from the interface module to the equipment... but no need to chase all new wires to the stat.
The IAQ will also control a heat pump, 3 heat stages and an ERV.
Maybe the Carrier unit works the same way -- I can't find any detailed docs so I just quoted from the furnace spec.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
Nope. The Infinity is a 4 wire. Been awhile since I played with one, but it does a whole lot more than a regular stat. Even tells you the static pressure. When you use the infinity stat, you wire to different terminals at the furnace than if you used a regular stat.
Well there must be a matching receiver unit that's used with the Infinity furnace, because it has no provisions for a 4-wire control with all of those functions.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
I believe you're thinking about AC units.
Family.....They're always there when they need you.
Nope.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
The salesman told me because of the size of my house - 3200 sq. ft. I would need a 95,000 BTU unit
So, was a load calculation done?
rattles the duct work
I bet, somewhere, there is PVC vent pipe pushing against the metal ducting.
It starts up and runs for 10 minutes and shuts off for ten minutes like clock work
Thats an odd one for sure. I would suspect a DIP switch setting on the board somewhere. That should be covered in the installation instructions... which, hopefully, they left for you. Troubleshooting without that information is sketchy at best.
The Payne furnace had a problem. A failure that resulted in a modification for free. Apparently the Co. would replace the secondary exchanger for free or give me $1,500.00 towards a new furnace. I opted for new. So I paid a total of $2200.00 for the new Bryant including install.
You paid 2200.00 to gain 5% efficiency and chose a middle of the road unit?.... Uh, ok.
A better choice would have been a variable speed two stage system with a two speed/variable speed inducer motor. *That* would have been quieter.
Edited 11/27/2008 11:30 am ET by danski0224