[sdcruiser]

I had about the same problem last heating season. One repairman said it needed a new control board and then online I read about the pilot ignitor. I replaced stark electrode and pilot burner and it seemed to fix it. The it started again so since I bought the control board online previous, I put that in too. Well it worked perfect all last season and a few days this year. Then it started acting up again. It lights the pilot and main burner but then both of those go out after maybe 2 minutes (sometimes). Then it will rapidly sort of click off and on like it's trying to start up again all the while the main blower is still running (as it should since it just shut down). I smelled gas awhile ago, disconnected everything and aired out the furnace room. I came home hrs later and started it again only to see it fail as described. Then when I tried again in about 10 min it ran right up to target temperature (10mins) like nothing was wrong.

I don't trust it anymore so it's become a manual system until I can fix or replace it. I'm about to dump $$$ on a new York Pulse unit unless anyone has any sage advice for me. It's 21 yrs old now. Thanks

[wmproop]

York is OK,, if it `s installed correctly

[sdcruiser]

I've got the symptoms down a little better now. Cold morning, 45 outside and 63 inside, heat off at thermostate. Turn heat on and furnace begins start cycle and warms for about 2 min. Then flame goes out and furnace runs cool down cycle with main fan running (has not hit target of 67 yet) then it once again initiates a light off and warms the house to the target temperature just fine. The next time it tries to warm it may work fine or it may cycle while it tries to light off the ignitor. I usually shut it off manually because I have smelled gas at this point. It has a new 3 wire ignitor assy and the main control board assy replaced last winter. Any thoughts on what I might replace while freezing in san diego (OK not really that bad) waiting for the quotes to come in. How about the temperature sensor right above the main burners? Thanks

[KC13]

Considering the action you describe and the parts you have replaced already, it sounds like you have a faulty pressure switch. The unit will attempt to establish pilot, but the absence of the pressure switch circuit is not powering the holding coil of the gas control. The pickup coil is dropping out when the pilot switches to the hot contacts. Since you haven't posted the model number, this would only be true if your furnace is an induced-draft design.

[sdcruiser]

It's the 58ss080CC. Yes it does have an air pressure sensing switch, large round device with the sensing line.

Funny thing is the first repair man said it was the board but then I put the ignitor in first and that "seemed" to fix it. But I had the board and when it acted up again I put that in because I could not get my money back. It operated fine all last season. But one estimator thought that it wasn't the board or ignitor but pointed out something in the draft induction system.

Looks like furnaceparts is out of this part. Is there anyway to jumper around this to check if it is the problem? There are 3 wires to it. One is NO (normally open), NC (normally closed) and C for common I think. It's a $90 part. If there's no way to jumper maybe I can "borrow" one from a neighbor. We all have the same 21 yr old Carrier.

Thanks for the advice. I see flashes from the board under the pressure switch when it starts cycling. I took all the board out today, cleaned contacts, inspected for missing solder, etc. It did the same thing and I can hear the valve opening and then closing maybe 30 secs later... when it senses no pressure generated I bet!

[KC13]

If poor or compromised draft conditions aren't a factor, it is likely that the switch contacts are oxidized, presenting an inconsistent problem that can be difficult to pinpoint. A voltmeter connected between NO and C would reveal if the switch circuit is breaking when the problem occurs.

[sdcruiser]

Your hunch was correct. I think the NC portion of the switch needs to stay that way to enable start up, the NO portion must close to keep the valve open. The NO of my switch is operating fine but the NC opens with pressure and causes the valve to close. So I jumpered it as it started so that both are NC and the furnace is running now. I need to confirm the flue is not plugged and I'm not bypassing this because of another problem. Does this sound right? It's now above 59 in the house thanks to you.

[sdcruiser]

Leave it to an Ohioan to help a former Ohioian. I'm in San Diego now. I found the part online for $71 and I'm looking in San Diego now. I checked the flue on the roof and no obstructions. The small fan is working but not sure about the larger one that makes the draft. Since the normally open portion of the switch does close I'm wondering if this means the inducer is making pressure? The NC portion opens causing the valve to close. I need to find a theory of operation somewhere I think. Thanks again.

[KC13]

If you jumpered NO to C and the unit sustains operation, that proves the switch was not maintaining the circuit. Make sure the switch circuit isn't breaking due to a problem with the combustion draft. The "flash" from the board? Likely the inducer relay arcing. If inducer operation becomes erratic this may be why.

[KC13]

Leave it to an Ohioan to help a former Ohioian. I'm in San Diego now. I found the part online for $71 and I'm looking in San Diego now. I checked the flue on the roof and no obstructions. The small fan is working but not sure about the larger one that makes the draft. Since the normally open portion of the switch does close I'm wondering if this means the inducer is making pressure? The NC portion opens causing the valve to close. I need to find a theory of operation somewhere I think. Thanks again.

What a coincidence... my oldest son lives in S.D. serves in the navy, stationed at Coronado.

[sdcruiser]

Small world. I've been here since 1971 and grew up in Cleveland.

I pulled the draw motor assy just to check. Everything seems normal for a 21 yr old carrier. I sealed it back up with hi temp rtv and I'm going to order the pressure sensor now. So can I send you some coffee. I roast as a side business and hobby and would like to pay you back for your willingness to share your knowledge. You saved me about $9K this year. I know one of these years I'll have to replace this thing along with the AC but not this year at least. Thanks again.

[KC13]

Small world. I've been here since 1971 and grew up in Cleveland.

I pulled the draw motor assy just to check. Everything seems normal for a 21 yr old carrier. I sealed it back up with hi temp rtv and I'm going to order the pressure sensor now. So can I send you some coffee. I roast as a side business and hobby and would like to pay you back for your willingness to share your knowledge. You saved me about $9K this year. I know one of these years I'll have to replace this thing along with the AC but not this year at least. Thanks again.

Sweet! I'd love some! Check your private messages.

[sdcruiser]

So the pressure sensor arrived today and I installed it. Plugged the unit back in and fired it up. Up until now I've been jumpering both contacts closed and it's been operating perfectly.

So the pilot lit, mains lit, it heated for about 2 min and then when I came back in from outside the pilot was again on and it was going through another start cycle which it did and it ran for many minutes just fine. I'm going to try it again but in the middle of the cycling I think it did THIS a time or two also. So I may be chasing two problems. I'm probably going to put something in this summer.

I got the quote for the Goodman 2 stage variable 95% and 16 seer AC along with duct cleaning and it's about $8K. I think the installer didn't want to believe my heat load calcs (I did several) and upsized the furnace and AC (4 ton instead of 3 ton). It may be because the smaller unit might not have enough air flow @ 1200 cfm for a 2100 sq ft 2-story house I suspect.

Oh the coffee was shipped out today. I don't think the Kona is that great but the Nicaragua is very good.

[sdcruiser]

I just tested it again and this time it started and ran for about 4.5 min at which time the pilot and main went out and system started cycling again, clicking on off on off.

So I jumpered it again, NO to NC and NC to NC and it started and ran just fine. I even jumpered the NC to NO while it was running and it ran fine and did not quit.

So I checked the switch while it was running and the NC goes to NO when burners are lit and the NO goes to NC. I didn't see it change until the burner shut off when it reached the set point. I'm not sure what the state is when it's cycling but the switch seems to be behaving as expected. I wish I knew what the NC and NO switch purposes were so I could trouble shoot this better. Looks like there's a new furnace in my future after all unless I can get this figured out soon.

[KC13]

NO is normally open, NC is normally closed, and C is common. At rest, C connects to NC, and NO is isolated. When running, C connects to NO, and NC is isolated. If possible, connect a voltmeter across C and NO, and observe meter when drop-out occurs. Unless switch is disengaging, you should read 0 volts.

[MarkwithaK]

I got the quote for the Goodman 2 stage variable 95% and 16 seer AC along with duct cleaning and it's about $8K. I think the installer didn't want to believe my heat load calcs (I did several) and upsized the furnace and AC (4 ton instead of 3 ton). It may be because the smaller unit might not have enough air flow @ 1200 cfm for a 2100 sq ft 2-story house I suspect.

As usual I have to say that I would steer clear of the variable speed motors. As far as oversizing your A/C, you have to be very careful about how you size the capacity. Most people do not realize that one thing the A/C system does is remove humidity from your house along with heat. On an over-sized system the heat will be removed but the humidity will not. This can cause problems ranging from an uncomfortable humidity level on up to mold issues cased by the humidity. Likewise, an over-sized furnace can have problems with the high limit if your duct work is not the correct size/configuration. Keep in mind that an improperly sized system could void any warranty.

[sdcruiser]

As usual I have to say that I would steer clear of the variable speed motors. As far as oversizing your A/C, you have to be very careful about how you size the capacity. Most people do not realize that one thing the A/C system does is remove humidity from your house along with heat. On an over-sized system the heat will be removed but the humidity will not. This can cause problems ranging from an uncomfortable humidity level on up to mold issues cased by the humidity. Likewise, an over-sized furnace can have problems with the high limit if your duct work is not the correct size/configuration. Keep in mind that an improperly sized system could void any warranty.

Yes that's my concern too with the 4 ton single stage system. The existing 10 seer 4 ton doesn't run all that long, however our humidity in San Diego isn't all that bad either. With a two stage AC (not offered in a Goodman until 5 ton) you have some flexibility. Two story houses of course really suffer without zoning because the upstairs is generally too warm on those few hot days where you need AC. So that's one reason all vendors here seem to ignore calcs and go with the rule of thumb. Even my worst case 40 deg day and 70 inside that yields about 28 K Btu/hr is ignored. I've checked it 3 ways including timing run time of the existing 72K Btu/Hr net unit and have come up with less than 30K every time. But they still want to install a 70-80K furnace.

Oh and the ducts are a nightmare with high noisey velocities on the two close downstairs ducts and only the one cold air return in the family room. The first register is only about 10 feet from the furnace and I've put a blue coarse filter in back of the register to quite it down. I won't go into how the cold air return was in the beginning but they utilized a false ceiling and hollow walls. When that didn't meet code they tried to put the cold air return right above the dryer in the wash room. The family room location was a compromise and I've added some baffling in the cold air return to quiet it down some. You can look into the cold air return and see the bottom of the furnace otherwise!

So I have heard the original variable motors had problems but that the latest generation has solved those issues that over-stressed many motors. Any truth to this?

KC, so far I've just looked at what the switch is doing statically. The resistanceof the NO portion when closed and furnace jumpered to run does creep from .05 K ohm to about .15 k ohm due to the temperature change but I don't see anything else unusual. Yet it works perfectly if I just jumper the wires as if everything is NC. For safety I disconnect the NO open leads once the furnace completes a cycle. I'm not sure if this is necessary and I'm too safety minded to run the furnace jumpered when I'm not at home. I'm sure I'm compensating for some other issue. I thought for sure the pressure switch would fix it. When it ran for 4.5 min perfectly I thought it was going to be OK but something caused it to "blow out" and then start cycling as if it was trying to re-start.

[MarkwithaK]

What calculations are you working off? Have you done a Manual J on the building?

So I have heard the original variable motors had problems but that the latest generation has solved those issues that over-stressed many motors. Any truth to this?

I have said this numerous times in other threads and let me repeat myself before those that praise the VS motor jump my back, my issue with variable speed motors is not their quality but their high repair/replace costs. Based upon rates in my area and my cost I can replace an entire system (high efficiency w/ conventional blower, 15 SEER condenser and Evap coil) for the same it would cost to replace a VS motor when you factor in labor and mark-up.

[sdcruiser]

Yes I can imagine the variables are costly. But if they last as long as a conventional is that really an issue? My conventional motor is 21 yrs old now. Is your experience that the variable need to be replaced more often. I'm sure the usage in your area is higher too.

[MarkwithaK]

Do not expect 21 years out of either a VS motor or a conventional motor for that fact. Quality just isn't the same. Newer parts are designed to eventually fail, that's just the harsh reality. Just to throw some numbers at you, to replace a VS motor you're looking at between $1000.00- $1200.00 easy and that is just for the motor. Factor in labor and you could up around $1400.00 If your local service company's mark-up is higher then obviously your total bill will also be higher.