Author Topic: pressure switch open and closed and open but not staying closed gmss921004  (Read 752 times)

Offline old furnace man

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Got a weird one here.
I get a no heat call with an error code pressure switch not closing cycle the power fires up no problem completes the cycle but on the next call for heat switch will not close switch is rated for.97"wc let it sit for 20min then try again unit fires getting 1.1" from the inducer port check draw on the ventor getting the proper fla  venting is good heat rise is 65 degrees found out the filter was plugged and changed before i arrived so the furnace was going off on limit so now bust out the analyser reading 10 percent co2 and over 100 ppm of co and exhaust temp of 115f  measured at the sidewall termination no water building up in the condensate backing up now here is when it gets weird let it cool down for another 30 min and turn it on with the blocked drain switch hose dissconnected so the gas valve will not open inducer pressure switch closes right away every time so i fire it for 20 seconds shut it off and try again now the switch is clicking closed and open repeatedly it seems the hotter the heat exchanger is the less vacum coming from the ventor port i think the heat exchanger is plugged or cracked but what do you guys think?

Offline NoDIY

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #1 on: November 19, 2017, 06:17:56 PM »
The over 100ppm has me thinking heat exchanger issues... The goodmans had/have issues with the gasket on the transition section between primary and secondary heat exchanger.

Offline old furnace man

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #2 on: November 20, 2017, 10:02:22 PM »
update
 I started out by calling goodman tech dept this morning as soon as they opened  gave him all my readings static pressure heat rise manifold pressure combustion analysis pressure changes in the ventor suction port in relation with the amount of time between cycles also I was allowed 40 of feet of venting with the number of 90s used and i had 31.5 feet of venting total I said the heat exchanger seems to have failed in some way he agreed so i went to my supplier ordered up the heat exchanger they say tomorrow so i say great done deal. Did you think it would be that easy I did for three minutes then i really found why garfield really doesnt like mondays the supplier calls back says the heat exchanger will be one to two weeks because it has to come from texas to ontario and the cant expitite it beacause they say that its too big a board a valve they say it could be but a heat exchanger no. fed ex or ups can but goodman won't. then it gets worse the supplier calls back with what i thought was good news but instead the heat exchanger is back ordered and it will be at least 5 weeks which is christmas so ill see it in the second week of january its november 20th right now. So the supplier gives me a number of some goodman big wig tech guy that can approve me a new unit or get me a new heat exchanger faster well victor didnt return my call then 2hrs later call again...... voicemail wait 2hrs more call again his time he rejects the call after the first ring thank goodness for goodman so i think about the relation of restistance and vacuum inside the furnace as an envelope so i talk to an ol feller who knows a thing or two about a thing or two so I have another opinion of someone who thinks like me that if i increase the venting to three inch I'll never have a problem again. Well so here I go rip out re drill holes and replace 31.5ft of 2" with 3" 5hrs later i'm done ready to fire up and test.... well temperature rise is lower furnace cycles properly combustion analysis is better pressure switch grabs everytime without hesitation hopefully i'm done with this one but just to add insult to injury when i realized i needed 2 45s not 2 couplings i went back to my supplier at the end of the day and the manager who i was hoping would have any kind of news on the tom f**kery going on with my situation and he slipped out the back door while i said hi to his old boss from 25 years ago when the manager was a co op student who mowed the grass and flipped burgers at our monthly bbq at the old ds fraser back in the day but here nor there the big thing with this situation is that i looked at the older revision of the goodman manual for the furnace and according to the gmss manual that i looked at the furnace can only run 25ft with the amount of 90s that i used with 2" venting I think the furnace was getting too hot inside possibly the seal between the primary and the secondary was becoming compromised as the furnace heated up with the restriction of the 2" venting even though temperature rise was 65 degrees and my supply temp was 15 degress below max. No matter what everything is running good now and i'm out 500 bucks material and a day's labour and woesley and goodman aren't gonna do nothing but have ostrich syndrome when i ask about the situation i'm in and how a contractor who's trying to do the right thing is getting the shaft in the end. But i guess that's the cost of being the boss.
Merry christmas

Offline walker

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #3 on: November 21, 2017, 06:24:40 AM »
The manual would have stated the max vent length, probably the first thing I would have looked at seeing a 100MBTU with 2" venting.  How are you out $500 in material did you not charge the customer for the repair?

Offline NoDIY

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #4 on: November 21, 2017, 10:59:22 AM »
So you are going to continue using it with the high co over 100ppm?  You corrected an installation error for sure..  But what about the potential defective heat exchanger?

I suggest you cap and disconnect

Offline walker

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #5 on: November 21, 2017, 11:40:53 AM »
So you are going to continue using it with the high co over 100ppm?  You corrected an installation error for sure..  But what about the potential defective heat exchanger?

I suggest you cap and disconnect

There is no code against a furnace producing over 100ppm CO, its more of an indication that something is out of line, anything over 400PPM should be red tagged.  Most Goodman furnaces come out of the box producing over 100PPM,  some of them have a defective seal on the primary to secondary header, some just require a manifold pressure adjustment, which is usually the case, I find lowering the manifold pressure from 3.5 down to 3.3-3.4 on most of them get it down to 20-40PPM CO.

Offline old furnace man

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #6 on: November 21, 2017, 05:51:20 PM »
walker the max vent length with 5 90s is 40 ft i had 31.5 i wrote that in my post did you not read that part?

Offline old furnace man

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #7 on: November 21, 2017, 05:54:54 PM »
no diy there was no error in the installation according to the instalation manual and the 149 and the enbridge inspector who inspected it and the goodman technical bulletin said under 200 is acceptable

Offline old furnace man

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #8 on: November 21, 2017, 06:07:11 PM »
now that we cleared that up yes im out 500 bucks and no i didnt charge the customer for goodmans problem it wasnt the customers fault how ever im still going to replace the heat exchanger when it arrives some time in january the 3" venting brought down the ppm of co as i said in my big paragraph you guys dont like to read the whole thing do you. me i read the manual cover to cover everytime i do an installation even if i put the same furnace last week because things change and it sucks to be caught with your pants down ive been doing this for over 30 years and ive never had a reject in all that time because people pay me their hard earned money to do a job correctly and look sharp too its not a smash and grab type of trade youre always accountable even 20 years after an install. So please read the whole thing before making comments.
Thanks

Offline walker

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #9 on: November 21, 2017, 06:28:44 PM »
now that we cleared that up yes im out 500 bucks and no i didnt charge the customer for goodmans problem it wasnt the customers fault how ever im still going to replace the heat exchanger when it arrives some time in january the 3" venting brought down the ppm of co as i said in my big paragraph you guys dont like to read the whole thing do you. me i read the manual cover to cover everytime i do an installation even if i put the same furnace last week because things change and it sucks to be caught with your pants down ive been doing this for over 30 years and ive never had a reject in all that time because people pay me their hard earned money to do a job correctly and look sharp too its not a smash and grab type of trade youre always accountable even 20 years after an install. So please read the whole thing before making comments.
Thanks

How is it Goodman's fault the wrong size venting was installed? 

Offline NoDIY

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #10 on: November 21, 2017, 06:31:05 PM »
I'd love to the see that goodman bulletin. please post.

Offline walker

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #11 on: November 21, 2017, 06:37:07 PM »
walker the max vent length with 5 90s is 40 ft i had 31.5 i wrote that in my post did you not read that part?

As per what you wrote...

"is that i looked at the older revision of the goodman manual for the furnace and according to the gmss manual that i looked at the furnace can only run 25ft with the amount of 90s that i used with 2" venting I think the furnace was getting too hot inside possibly the seal between......"

The manual stated you could only do 25ft with 2" and you had 31ft...  Did you even read your own rant?

Offline NoDIY

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #12 on: November 21, 2017, 06:44:14 PM »
OK so it was incorrectly vented according to the manual that was shipped with the furnace.. Got it.. Good that you corrected the error.

 

Found that bulletin on CO
http://www.hvacdist.com/Tech%20Svc%20Bulletins/AMANA/SF-041.pdf


Offline old furnace man

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #13 on: November 21, 2017, 09:26:23 PM »
seriously you guys really didnt read the rant at all. you guys skimmed the paragraph again i've attached the service bulletin the 2014 installation instructions and the 2017 installation instructions to show the ppm issue and the fact the venting is according to the manual of the time of installation http://www.hvacdist.com/Tech%20Svc%20Bulletins/AMANA/SF-041.pdf then the 2014 http://www.shop.thefurnaceoutlet.com/media/GMCSS9-INS.pdf then the 2017   https://www.alpinehomeair.com/related/Goodman%20GMSS9%20GCSS9%20Installation%20Instructions1.pdf in the rant when i said older manual i meant the furnace was installed this year and ran fine for months  now ive shown you my supporting documentation to prove what iv'e said already are we in agreement that ive vented the furnace in the first place with the 2" venting according to the manual shipped with the furnace? again if you guys arent reading the whole thing again the furnace was installed in march of this year. i know the goodman bulletin has already been posted but i posted i again if anyone didnt read it. So did you guys actually read this whole thing this time?

Offline Porcupinepuffer

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #14 on: November 22, 2017, 04:09:59 AM »
 I'm just a little confused. What manual was shipped with the furnace? The one where the 2" venting was only good to 25', or the one where the 2" venting was good for 40"?

I go with the manual that comes with the furnace... You do have slight differences in the model numbers. One manual lists them with an "a" at the end. The other doesn't.

Offline old furnace man

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #15 on: November 22, 2017, 08:03:17 AM »
 Porcupinepuffer the furnace was installed this year and came with the 2017 manual which allows 40ft of 2" venting with 5 90s the "old" manual that does not pertain to the 2017 furnace says 25ft with 5 90s on 2" in my last two posts ive said old manual im really starting to think you guys are just trolling me i described it in the rant of the difference in manuals. ive looked at all the revisions for the manuals from2014 to2017 and in the 2014 you can only go 25ft and in the 2015 you can go 40ft.

Offline Porcupinepuffer

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #16 on: November 22, 2017, 12:53:31 PM »
Nobody's trolling. It's a little hard to decipher with the lack of periods and run-on sentences. Even reading it in my head I was losing my breath a couple times.

One second I'm reading about venting, and then the next second I'm reading about co op students, flipping burgers, and ostrich's.

Personally, I would have made sure I was getting paid for changing out the venting before touching it. I don't know about anyone else, but we pay quite a bit more for the materials when we jump from 2" to 3" pvc.

Offline NoDIY

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #17 on: November 22, 2017, 04:20:45 PM »
Ya no trolling.. I lost track of what was written a few times.. The lack of punctuation and ramblings on made it hard to understand..


That said.  Even though you helped make the pressure switches by exceeding well past what you needed to vent it.. As you said. It was installed correctly initially.  It didn't make pressure switch and has CO over 100PPM before upsizing the vent. My concern is the secondary.. Is it possible the gaskets connecting both heat exchangers are leaking as they are known to do on Amana and Goodman? Is it possible that reducing the vent restriction could mask the effects of the leaking gaskets?.

What the the CO readings now?

Not trying to be an ass we are not on site.  so we are all just speculating based on the information or lack of information given..

I get Amana says up to 200pm is acceptable but, typical readings is well under 100ppm for most if not all residential furnaces.. It raises my attention when I see CO over 100ppm.. Reminiscent of carrier heat exchanger failures the CO did not sky rocket overnight


Offline walker

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Re: pressure switch open and closed and open but not staying closed gmss921004
« Reply #18 on: November 22, 2017, 06:06:00 PM »
Amana/Goodman have since fixed the issue with the gasket coming apart.  That was seen on the older models 2011 and earlier if I recall correctly, a 2017 should not be experiencing that issue, unless it's a newer problem that hasn't been addressed as of yet. 

I would get a hold of Victor again, and maybe get him on site. 

He's helped me in the past on a few weird ones.