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Good evening all. It appears the culprit is an intermitantly operating barometric bypass damper.Thanks for the comments & suggestions. Hopefully the problem is solved. Will replace the damper next week when I return to Carolina.

It does re-enter close to the return plenum. thanks on the plexiglass tip.

This is an air handler manufactured by "The First Company" that has an evap. coil upstream, or on the suction side of the fan, with a hydronic hot water heating coil on the pressure, or discharge side of the fan.

Originally Posted by steamdrm

We took readings on the A/H return inlet, and the A/H outlet.

So one of the readings was taken between the evaporator coil and blower unit?

What is the bypass for? Is it zoned?

I would certainly look into that bypass. How does it enter return close to evap coil?

Another trick is plexiglass panel to see exactly where the water is coming from.

We took readings on the A/H return inlet, and the A/H outlet.

Where exactly did you take your TESP readings?

It does seam a bit low, the coil alone should have more static than that

No open air returns, but it does have a prior existing Carrier barometric bypass damper off the supply duct. The damper shaft indicator shows closed, but it could be leaking through.

Originally Posted by drife678

Is the condensate line trapped properly?

The condensate line is in fact properly trapped. The coil is mounted below the fan and the fan velocity appears to be "sucking" or lifting the condensate off of the coil.

Is the condensate drain sucking in air? It should have a trap that is vented on the downstream side (not the pan side) and it should make a good seal. If the trap is not deep enough or there is no seal, and the trap is on the negative pressure side of the fan, it could be sucking air in through the condensate drain which can cause water to be flung everywhere and it seems like this would lower your external SP but not sure to what degree.

Is the condensate line trapped properly?

Need to see some pics of how coil is positioned.

That is pretty low static. Does it have open air return?

Relocated to "Tech to Tech"

Is it a standard blower motor or ECM? I went to a call with an ECM wound out and would not ramp down no matter what I did. (>1 year old) I swapped out the motor....open the door, get on the floor, everybody walk the dinosaur. I did not check static pressure though....hmmm

Condensate Carryover

Good evening,
I replaced an existing 4 ton air/air heat pump with a 4 ton straight cool/ hot water hydronic coil air handler.
The new air handler sucks or pulls the condensation off of the evaporator coil and slings it throughout the interior of the air handler cabinet.
The new evap. coil has been cleaned of any manufacturing oils. External duct static seems to measure around .2" WC.
The manufacturer's rep. says there is no way the ESP can be that low. I'm mainly a boiler guy and this is a project at my own home, and I'm looking for help.
Thanks