Thinking of replacing our NEW Gibson Furnace [Archive] - Glock Talk

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Mr King
12-22-2012, 10:16
In Jan 2011 our old dinosaur of a furnace (circa 1950) finally gave up the ghost. This happened during the coldest part and week of the year.

We called a furnace repair shop and they told us it would be cheaper to just replace it with a new one than to find the parts would cost (if they could even find them) for our old furnace.

So, we went ahead and replaced our old furnace with what the furnace company had in stock, which was a Gibson Furnace. The only thing that wasnt replaced was the thermostat on the wall. (which is also quite old)

Anyway, we just are not happy with the heat produced by this new furnace. The blower works fine and more air comes out of the vents than ever before with the old furnace, however, its just not keeping the house as warm as the old furnace, even with the thermostat turned wayyy up.

I checked the size of the furnace against the size of the house and it supposedly is to be the correct size, so I just dont know what else to do other than replace the furnace yet again, with another furnace, that sure wont be a Gibson Furnace.

Im toying with the idea of replacing the thermostat before I go ahead and replace the furnace again, but im not really sure that would help.

Any suggestions would be great! :wavey:

HollowHead
12-22-2012, 10:30
Most of the HVAC guys here blow a gasket at the mere suggestions of a layman, but here goes. We had the exact same thing happen and it turned out to be the old thermstat. The swing setting / cycle rate / anticipator settings / line voltage? for the old furnace were wrong and could not be made compatible with the new one. A call to the new furnace manufacturer fixed this with a $30 thermostat from Ace... HH

davew83
12-22-2012, 10:32
Thermostat first.
Why wasn't that changed when the unit was put it?

Mr King
12-22-2012, 10:33
http://www.diy-ha.com/images/Thermostat.jpg

This is the type we have right now.

The place that sold use the furnace said there was no need in changing the thermostat, thats why it wasnt changed.

FullClip
12-22-2012, 10:34
Changing the thermostat won't help anything with the heat that the furnace is putting out. It would be a good move to change to a programable thermostat to help save a little fuel by lowering the settings automatically while you're asleep or at work.

If the furnace is blowing more air through it than the old one, that may be part of the problem. The faster the air goes through the heat exchanger, the less heat it can pick up. Slow the air down, and while you won't feel such a breeze at the registers, it will be warmer sooner. But even with a high air flow, the place should eventually warm up to the thermostat setting.

Did the company that installed the new unit do an air balance to check the flows to the various registers?

davew83
12-22-2012, 10:35
Get a Honeywell Pro 5000

Restless28
12-22-2012, 10:37
Most of the HVAC guys here blow a gasket at the mere suggestions of a layman, but here goes. We had the exact same thing happen and it turned out to be the old thermstat. The swing setting / cycle rate / anticipator settings / line voltage? for the old furnace were wrong and could not be made compatible with the new one. A call to the new furnace manufacturer fixed this with a $30 thermostat from Ace... HH

Never heard this before. Thanks.:wavey:

FullClip
12-22-2012, 10:37
http://www.diy-ha.com/images/Thermostat.jpg

This is the type we have right now.

.

Change the thermostat! That one belongs in a museum. it won't fix your furnace heat output, but you'll have a little mercury to play with from the old one!!:supergrin:

Mr King
12-22-2012, 10:39
Did the company that installed the new unit do an air balance to check the flows to the various registers?


I don't know as I wasnt here when they replaced the old furnace.

HollowHead
12-22-2012, 10:40
Never heard this before. Thanks.:wavey:

Neither did the clown who installed the funace. He also didn't check the NG line pressure and failed to adjust for the inches of water it presented with. This is what we got getting a furnace replaced on the coldest day of the year... :rofl: HH

Mr King
12-22-2012, 10:48
the furnace is a gibson 80+ AFUE thermostat SK Downflow model, what thermostat would be the correct one?

FullClip
12-22-2012, 10:48
Is your new unit a 2 stage combustor?

If it isn't set right you could only be getting about 68% of the heating capacity from the first stage. check out this link and it may help. The company that installed the unit should have explained how it works and maybe they set it up wrong and the 'after-burner" isn't kicking in for you.

http://www.gibsonhvac.com/GasFurnaces.htm

I've got an oil fired boiler for my heat, wish I could get the efficiency of a gas unit...but no pipe line near me.

Mr King
12-22-2012, 10:52
Is your new unit a 2 stage combustor?

If it isn't set right you could only be getting about 68% of the heating capacity from the first stage. check out this link and it may help. The company that installed the unit should have explained how it works and maybe they set it up wrong and the 'after-burner" isn't kicking in for you.

http://www.gibsonhvac.com/GasFurnaces.htm

I've got an oil fired boiler for my heat, wish I could get the efficiency of a gas unit...but no pipe line near me.
it says its a single stage high effieiency gas furnace.

FullClip
12-22-2012, 11:10
it says its a single stage high effieiency gas furnace.

Well, then I'm kinda' at a loss for the fix...was hoping it was the two-stage deal.

Give the installers a ring and see if they'll come out and check it out, or maybe somebody here on GT can offer more advice on a fix.
If the burner is running but you can't heat the house with it, either it's too small a unit or it's wicked wiicked dirty and you've not getting the heat transfer from the combustion to air heat exchanger.
have you checked the duct work for leaks where it may be pulling in cold air?

Mr King
12-22-2012, 11:12
have you checked the duct work for leaks where it may be pulling in cold air?

I had a buddy of mine check the ductwork and I know for a fact that the ducts are tight. I had him do that last summer.

Fastbear
12-22-2012, 11:27
Change the thermostat! That one belongs in a museum. it won't fix your furnace heat output, but you'll have a little mercury to play with from the old one!!:supergrin:

For what its worth here, we have a 120 year old two story expanded home built around 1887. In 1938 my grandfather purchased this property. He had the original coal furnace converted into two NG floor furnaces which used 120VAC for thermostat regulation and opening the gas solenoid. When wife and I purchased this property from Dad six years ago the larger gas furnace had a small pilot leak. The older gas man came over and converted both furnaces to thermocouples. The units now generate their own electricity for the purpose of thermostat regulation (mercury switch) and opening the solenoid. The newer thermostat (programable) on one had to be replaced with a mercury switch. The orignal thermostat was a Honeywell. Now, the electric company can drop power and guess what. The house stays warm because the old floor furnaces generate their own electricty. Some old things still work for the application.

misunderestimated
12-22-2012, 11:35
So when we talk about comfort is not the same its hard to diagnose this as a problem. So some simple questions

If you set the thermostat to 70 degrees will it make the house 70 degrees and then shut off? if yes then the unit is mechanically working,

So now what makes you feel uncomfortable?

When we replace an old 62 year old unit we explain to the customer your old unit may have had air blowing out as hot as 180 to 200 degrees even hotter if its been modified by past repair guys putting wrong size blowers and other after market repair parts.A new furnace may only put out 140 degree discharge air and if the duct work is uninsulated or in outside walls or exposed to the outdoor temps it may not feel like its working but it is .

Is this a trailer or a manufactured home/ this is where most of the complaints come from and i explained why

The solution is to lower the blower speed and then insulate the ducts

the higher the blower speed the lower the temperature of the air coming out

FullClip
12-22-2012, 11:43
For what its worth here, we have a 120 year old two story expanded home built around 1887. In 1938 my grandfather purchased this property. He had the original coal furnace converted into two NG floor furnaces which used 120VAC for thermostat regulation and opening the gas solenoid. When wife and I purchased this property from Dad six years ago the larger gas furnace had a small pilot leak. The older gas man came over and converted both furnaces to thermocouples. The units now generate their own electricity for the purpose of thermostat regulation (mercury switch) and opening the solenoid. The newer thermostat (programable) on one had to be replaced with a mercury switch. The orignal thermostat was a Honeywell. Now, the electric company can drop power and guess what. The house stays warm because the old floor furnaces generate their own electricty. Some old things still work for the application.

The thermostat just starts and stops the heating system, or in some types of systems sends the signal to the valves or dampers that need power to operate the electric motors or solenoids. How are the fans (hot air) or zone pumps (hot water) work without electricity?
In example my place I need power to the burner (fuel pump and combustion air fan) and the three zone pumps. The voltage from any thermocouple is pretty small, and of course it isn't AC current, so it ain't gonna power any motors that need power to run the furnace or boiler.

Mr King
12-22-2012, 11:45
So when we talk about comfort is not the same its hard to diagnose this as a problem. So some simple questions

If you set the thermostat to 70 degrees will it make the house 70 degrees and then shut off? if yes then the unit is mechanically working,

So now what makes you feel uncomfortable? {{{{{{{{im comfortable at about 70 but, the furnace thermostat at this moment is at full blast and its just 70 in here now. this is during the warmest part of the day.}}}}}}}}}}}}}

When we replace an old 62 year old unit we explain to the customer your old unit may have had air blowing out as hot as 180 to 200 degrees even hotter if its been modified by past repair guys putting wrong size blowers and other after market repair parts.A new furnace may only put out 140 degree discharge air and if the duct work is uninsulated or in outside walls or exposed to the outdoor temps it may not feel like its working but it is .

Is this a trailer or a manufactured home/ this is where most of the complaints come from and i explained why

The solution is to lower the blower speed and then insulate the ducts {{{{{This is a 100+ year old home}}}}}}}}

the higher the blower speed the lower the temperature of the air coming out

{{{{{{The furnace blows out hot air from the ducts but its not always hot air it blows out, often its just air and not warm at all}}}}}}

RenoF250
12-22-2012, 12:33
I would sit and watch it and see if the burner is cycling off. You may have a bad over-temp switch that thinks the burner is getting too hot and turning it off. Or it may actually be getting too hot because of insufficient airflow.

sawgrass
12-22-2012, 12:40
In Jan 2011 our old dinosaur of a furnace (circa 1950) finally gave up the ghost. This happened during the coldest part and week of the year.

We called a furnace repair shop and they told us it would be cheaper to just replace it with a new one than to find the parts would cost (if they could even find them) for our old furnace.

So, we went ahead and replaced our old furnace with what the furnace company had in stock, which was a Gibson Furnace. The only thing that wasnt replaced was the thermostat on the wall. (which is also quite old)

Anyway, we just are not happy with the heat produced by this new furnace. The blower works fine and more air comes out of the vents than ever before with the old furnace, however, its just not keeping the house as warm as the old furnace, even with the thermostat turned wayyy up.

I checked the size of the furnace against the size of the house and it supposedly is to be the correct size, so I just dont know what else to do other than replace the furnace yet again, with another furnace, that sure wont be a Gibson Furnace.

Im toying with the idea of replacing the thermostat before I go ahead and replace the furnace again, but im not really sure that would help.

Any suggestions would be great! :wavey:

Replace the thermostat. Also the fan speed might be set too high. This prevents the needed time for the heat to exchange from the combustion process to the return air.

Some things to check are:

Temp rise
Gas input/clocking the meter
Orfice size
Duct size

Good luck and Happy Holidays.

davew83
12-22-2012, 12:42
Sounds like the burners aren't firing for some reason. Again start with the thermostat and go from there.

sawgrass
12-22-2012, 12:46
Change the thermostat! That one belongs in a museum. it won't fix your furnace heat output, but you'll have a little mercury to play with from the old one!!:supergrin:

That old T87 is one of the most reliable thermostats ever made. Too bad we can't continue to install them.

sawgrass
12-22-2012, 12:50
Here is a very basic 'sequence of operation' for most modern gas furnaces.

1. Power to the furnace
2. The door switch is closed
3. 24 volts to the thermostat on “R”
4. The thermostat calls for heat
(R-W closes)
5. Furnace checks to see the pressure
switch open
6. The induced draft motor starts
7. The pressure switch closes
8. The circuit board verifies that the
safeties are closed
9. The ignitor glows, trial for ignition
10. The gas valve opens
11. The burners ignite
12. The flame sensor proves
flame
13. After a time delay the
indoor blower starts
14. The furnace warms the
space to setpoint
15. R-W opens
16. The gas valve closes
17. The flame goes out
18. The blower times out
and stops
19. The system waits for the
next call for heat.

misunderestimated
12-22-2012, 13:11
{{{{{{The furnace blows out hot air from the ducts but its not always hot air it blows out, often its just air and not warm at all}}}}}}

Some furnaces have a timer in them that allows the gas valve to come on and heat the furnace up before it blows cold air out, then once it satisfies the thermostat and the gas valve goes off it then turn off the blower after a predetermined time.

Some units use a temp sensor to complete the same thing

Regardless of how its done the unit should not blow out cold air unless something is malfunctioning . If the unit is oversize for the duct work it cant get rid of its heat and cycles on it limit and then shuts off the gas but the leave the blower running till you do a soft reset that may be as simple as Turing the thermostat off or resetting the power to the unit

A quality HVAC technician should be able to diagnose the problem real quick with some simple measurements

misunderestimated
12-22-2012, 13:13
That old T87 is one of the most reliable thermostats ever made. Too bad we can't continue to install them.


Yup it was a great design if we could only get past that tiny mercury situation

Hicksville Kid
12-22-2012, 13:18
I also agree with the thermostat replacement guys.

Remember the old adage......replace the cheapest thing first.

Mr King
12-22-2012, 16:53
Thank you all so much for all the info so far! I have purchased a Honeywell digital to put in, hope this fixes everything, ill report back when i can about how it does. thanks again!

RonS
12-22-2012, 17:33
You never know what you are going to get when you have someone come fix something.

Last year my best friend had his furnace/heatpump replaced due to a part failure. His 10 year old furnace had never worked right, his gas bill was high but the house never got really warm.

When the new HVAC people came to install the new unit they checked things out and found that the cold air return in the attic had never been completed when the old unit was installed ten years ago.

Two years ago my mother had a new electric furnace installed in her upstairs appartment. It never got warm. My BIL finally figured out that it was wired wrong. Don't have the details but whenever it called for heat only half the unit came on. I would think that colorblind people would not take jobs as electricians, but that was the companies excuse, the electrician was colorblind and couldn't figure out the wiring.

G17Jake
12-22-2012, 18:25
If you installed a high efficiency furnace, the new thermostat may fix things for you. There is something about the cycle rate and heat anticipator that is different for HE furnaces.

sawgrass
12-22-2012, 18:39
If you installed a high efficiency furnace, the new thermostat may fix things for you. There is something about the cycle rate and heat anticipator that is different for HE furnaces.

Most newer furnaces have to be set up with a series of dip switches on a circuit board. Few installers know how to do this properly. If he replaces the T87 with a new stat, it may be able to determine heating needs through memory. An actual heat anticipator that is set based upon gas valve amperage (wrapping a wire ten times....never mind)

Mr. King, thankfully my days of running service over the holidays are behind me, but I'll help you if you get stuck.

'cause you gotta love a Colt's fan'

LEO/Dad
12-23-2012, 07:20
From: misunderestimated........Thanks!

"Regardless of how its done the unit should not blow out cold air unless something is malfunctioning . If the unit is oversize for the duct work it cant get rid of its heat and cycles on it limit and then shuts off the gas but the leave the blower running till you do a soft reset that may be as simple as Turing the thermostat off or resetting the power to the unit

A quality HVAC technician should be able to diagnose the problem real quick with some simple measurements"

I retired in Sales/HVAC Distributor. We had a contractor that was old school and just didn't want to attend training on the new furnaces. He was retiring soon, so we didn't want to cut off his sales. He had a really good reputation in his rural community. One day, a competing contractor in this same rural community told us a story about being called by the customer of said contractor about a problem similar to this. The guy kept changing things, but just couldn't solve the problem. Dick told us the problem was the return air just wasn't big enough. The new furnaces move so much more air, the furnace was overheating, and shutting off and cycling on the high limit. Dick changed the return air, problem solved, customer happy. The T87 Honeywell is still available as T87N w/o mercury switch.

Z71bill
12-23-2012, 07:33
Long shot - but I seem to recall something about --

The fan should blow a different volume of air depending on whether the AC (cold) or heat being on.

If the blower motor is running too fast - high volume of air with the heat on - a high efficiency unit will not function as well - slower air flow will actually give you more heat.

Or is this only with electric heat?

Mr King
01-14-2013, 13:19
Sorry for not getting back sooner on this, but our problem is solved.

The Problem was that I was using the dense hepa type filters which in turn caused heat to build in the furnace and it would shut itself down.

Who would have thought that I was doing the wrong thing trying to get any pollen and animal hair out of the air was a bad thing? :/

The thermostat was not the problem at all.

Thank you all for all your help. :)

Cybercowboy
01-14-2013, 13:25
Sorry for not getting back sooner on this, but our problem is solved.

The Problem was that I was using the dense hepa type filters which in turn caused heat to build in the furnace and it would shut itself down.

Who would have thought that I was doing the wrong thing trying to get any pollen and animal hair out of the air was a bad thing? :/

The thermostat was not the problem at all.

Thank you all for all your help. :)

Indeed! We have a nice new unit that replaced our 15-year-old system last August. We use inexpensive but good paper filters and change them religiously every month. We have concrete floors and several cats so that is important.