Hey everyone on the HVAC forums, I am having a bit of a problem with a furnace. Ill give you the details...
Model: Goodman GMSS920403ANAA
Parts catalog and exploded views: https://cdn.daikincloud.io/PIM/Assets/Documents/143576.pdf
PROBLEM:
1. Furnace will start as normal and light and blower will initiate.
2. After about a minute of run time the flames cut out but blower will remain on.
3. Furnace will then go through the restart sequence (30 sec or so) and relight the flames*
4. After about 10 sec to 60 sec (average 30 seconds) the flames will go out and this cycle will continue until thermostat temperature is reached. Then furnace will do a normal shutdown.
*Note: if the furnace is off for awhile (while I was working on it) the first flame cycle may not fail until 3 minutes into flame ignition, however, after this, the cycle will continue at an average of 30 seconds flame run time from then on.
(board has led diagnostics but is steady red [normal operation] through the whole process)
What I have tried.
1. Replaced flame sensor
2. Vaccumed out P-trap (and drain hose) and re-primed it.
3. Took out and inspected limit switch and verified continuity.
4. Checked pressure switch hoses for cracks or holes.
5. Checked intake and Flue gas outlets for blockage
Currently I have a board on order (PCBBF136) and plan to swap it out to see if the current one is faulty. I want to do this with the pressure switches as well. However I cannot find a replacement for the 2-stage pressure switch system anywhere [part #] (0130F00430)
My 2 questions are:
1. What might you think is causing the cycling problem?
2. I want to get a spare 2 stage pressure switch system as a spare part/test to work the problem and need help locating it or an equivalent. Where might I find one?
The manufacturer details on each of the pressure switches are as follows:
PW1: -0.20 PF ---- 9375VD-0290 ----Air Proving ----0130F00641 ---- SN:435216/00646 ---- Costa Rica ----43/17
PW2: -0.10 PF ---- 64-0491-A-00 ----Blocked Drain ---- SN:435231/04122 ---- Costa Rica ---- 43/17
Thank you for your time and any help you might shed on this elusive problem.
This does look like a problem with a drain. Water level in the collector box intermittently causing pressure switch to open. This is why if you leave it alone long enough for condensate to gradually manage to drain out, it'll work few min longer. But the moment water builds up again, it'll return to the same issue.
Did you clean the little tubing that goes between the collector box and the drain trap?
If I recall correctly (didn't even read your model. Just going off experience with high eff Gooan's), that pressure switch is in series with the gas valve. So when it opens, it interrupts gas flow. So it would never give pressure stuck open error, it'd give you a flame lockout.
I took all the water lines apart and vacuumed them out but the problem still persists. I think that you are on to something but it will be some time before I can take apart the inducer and inspect the secondary heat exchanger to see if the water problem starts there. (or to see if there is a blockage within) Perhaps in a week or so when it isnt -20 right now.
Use an electrical meter and see where the disconnect is. It could be your high limit opening. Use a clean filter and open all of your registers.