Lennox unit no Mod & Ser tag
#1
01-06-18, 11:30 AM
Lennox unit no Mod & Ser tag
No heat call @5*F and -20 wind chill. Lennox RTU, No data tag, schematic indicates a GS16-(maybe 036)... gas / electric PKG.
control compartment packed in snow, cleared out same. #1097-4025 IFC board. unit @ 3.6" WC, fan runs OK vac hose OK. all logs lit and steady, unit trips intermittently on code 2 ( flame failure) during heat cycle after about 3 to 5 min, and two more times then locks out... flashes a 2 code, but I can hear the ignition continuously sparking afterward, while in lockout.... sensor rod was also removed & cleaned. I believe the board must be bad... your thoughts. gas pressure on manifold was steady, till it cut out. Did not however read supply side. Too dam cold. another weird thing, gas pressure was up to 8"wc upon initial light off but quickly comes down to 3.6 and steady. haven't seen one shoot up like that and then come down in about 2 seconds.
control compartment packed in snow, cleared out same. #1097-4025 IFC board. unit @ 3.6" WC, fan runs OK vac hose OK. all logs lit and steady, unit trips intermittently on code 2 ( flame failure) during heat cycle after about 3 to 5 min, and two more times then locks out... flashes a 2 code, but I can hear the ignition continuously sparking afterward, while in lockout.... sensor rod was also removed & cleaned. I believe the board must be bad... your thoughts. gas pressure on manifold was steady, till it cut out. Did not however read supply side. Too dam cold. another weird thing, gas pressure was up to 8"wc upon initial light off but quickly comes down to 3.6 and steady. haven't seen one shoot up like that and then come down in about 2 seconds.
Last edited by hvac01453; 01-06-18 at 12:00 PM. Reason: additional data
#2
01-06-18, 01:14 PM
Group Moderator
See if these manuals for a GCS-16 are your unit.......
Lennox_GCS16.653.pdf
Tech_Spec_gcs16_2-5.pdf
3.6 WC is very close to stated manifold pressure of 3.5 +/- .03
Lennox_GCS16.653.pdf
Tech_Spec_gcs16_2-5.pdf
3.6 WC is very close to stated manifold pressure of 3.5 +/- .03
#3
01-06-18, 02:23 PM
Lennox links
The bottom link was more like the unit. The top one is 89 vintage, my schematicis dated 8/03, it also has about 5 horizontal tubes with the cone ends like a jet, instead of the sealed chamber style. I also removed a few wasp mud packs on the gas tube tops where primary air gets mixed, as well as bees nests. I have noted thus far, it must be a 2-3 ton due to the OAD16-41 air damper for that cabinet. I thank you for the link..
What else do you think I should check ? I hate replacing parts willy nilly. When I saw all the snow packed all over the board I thought it was that, for sure. Especially when it locked out and the indoor fan stopped also, all well and fine, flashed a code 2 , and then I could hear the sparker zapping like crazy, I though I had an electrical high voltage short somewhere with all that snow being in there at first till I saw the electrode zapping like crazy during this lockout. I thought, this isn't normal, something in this board is toast.
Mike
What else do you think I should check ? I hate replacing parts willy nilly. When I saw all the snow packed all over the board I thought it was that, for sure. Especially when it locked out and the indoor fan stopped also, all well and fine, flashed a code 2 , and then I could hear the sparker zapping like crazy, I though I had an electrical high voltage short somewhere with all that snow being in there at first till I saw the electrode zapping like crazy during this lockout. I thought, this isn't normal, something in this board is toast.
Mike
#4
01-06-18, 03:37 PM
Group Moderator
Yeah.... with the board in lockout.... there should not have been ignition.
If your back is against the wall for a repair.... pull the board. Take it inside and check for visible water damage or corrosion that could be cleaned. Possibly just drying the board out well could help.
If your back is against the wall for a repair.... pull the board. Take it inside and check for visible water damage or corrosion that could be cleaned. Possibly just drying the board out well could help.
#5
01-07-18, 10:05 AM
at ninety something an hour, I don't think its cost effective enough to do, and almost all articles I've read online say if it ever gets wet to replace it. Now snow and wet, well theres a fine line there, both are conductors and I never actually saw water droplets on the board but during the run cycles Im sure some of the snow dusting may have melted or it got wet before I got there while it was warm in that section. It started to work again after another reset. Starting to think maybe a gas supply problem may have been involved. That was the only gas pressure I didn't check, it was just so cold...
#6
01-07-18, 11:45 AM
Group Moderator
I thought this was your unit. I don't recall you mentioned servicing it for someone else.
I do know one thing..... when heat is needed NOW.... you do what you can. If you don't want to spend the time on the board.... it would be prudent to replace it.
I do know one thing..... when heat is needed NOW.... you do what you can. If you don't want to spend the time on the board.... it would be prudent to replace it.
#7
01-08-18, 09:53 AM
Board replacement?
Well, now being 3 days later, and the temps have come up to a sweltering 29*F, The Unit is running fine and heating. Customers are reluctant to replace anything when it is working. Thanks for the advice. Just like to bounce things off others in the field.
Mike
Mike
