Coleman Evcon Model#DGU04008UC Blocked condensate syst error

[slrox]

I had an error code 3 flashes which is “pressure switch stuck open”. After I checked and disconnected the pressure switch (vertical diaphragm valve part# 024-25997-000), I noticed water inside the membrane area. I drained and installed back and it was running fine for 8 days.
After I got 10 flashes error code which means “blocked condensate system”.
It ignites and burns for 1 minute and shuts down again for 1-2 min. 10 flashes. Ignite and burn for 1 min. And it’s happening for 7-10 times until a continuous run.
What should I check? Why is coming water inside the pressure switch?

Please help

[hvac1000]

You have a condensate drain on that furnace. Check to see if it is plugged up or restricted. The water you are seeing is supposed to drain from the unit to the outside.

[slrox]

I checked the condensate water drains / pipes and nothing is obstructed or clogged.
But water is still collecting in the combustion air blower and eventually in the pressure switch.
And the symptoms are the same: 10 flashes error code which means “blocked condensate system”. It ignites and burns for 1 minute and shuts down again for 1-2 min. 10 flashes. Ignite and burn for 1-2 min. And it’s happening for a few times until a continuous run.
From where else can the water get into blower and pressure switch?

[hvac1000]

Water is supposed to drain from the secondary heat exchanger. Obviously that is not happening since you are having this problem.
On many units there is a way to adjust the sealed combustion pressure but you would need a digital manometer. The old water style tools do not work well in this category. Water is being held or forced back and not out. Could be that Robert who has more experience on these type of units will chime in on this. One thing you may also check is to make sure your discharge flue vent pipe (the one that runs warm to the outside is not partially restricted.)

Many systems depend upon some vapor loss from this to balance the system.

[slrox]

I checked the manifold pressure and it was as prescribed by manufacturer: 3.5".
One thing my HVAC guy pointed out: the tiny hole on the pressure switch where the hose from the ventor-motor to the pressure switch goes in was obstructed. He used a thin wire to make sure is free of dirt. His explanation for the water in the pressure switch and hence the 10 flash error for blocked condensate system: the tiny whole being clogged a negative pressure sucked the water from the blower.
I watched if the error occurs again. It happened once, but maybe is still draining the accumulated water in the blower.
Does it make sense?

[hvac1000]

Yes it does. Glad he got it going for you.