P Trap Hvac Condensate Drain Line Design

Fan inlet pressure negative h figure 3.

P trap hvac condensate drain line design.

If fan is located before the coil in the system the fan will push small amount of air and water down condensate drain. Minimum h fan outlet pressure in. See when moist air hits something cold the water condenses out of the air and collects on the cold surface. What is a p trap you say.

Condensate comes from evaporator coil. Minimum maximum sea level. If fan is located upstream of coil fan will pull water up drain line counter to water flowing down. Trap for draw thru unit condensate beginning to drain away.

Traps with insufficient height between the inlet and outlet design deficiency on draw through systems can cause the drain to back up when the fan is on possibly causing. Co ndes at r i p r ec om ndati. W c 1 in. Condensate switches imc 307 2 3 states that all hvac equipment that produces condensate must have either a secondary drain line or a condensate overflow switch a secondary drain pan with a secondary drain line or condensate switch or some combination of these installations should be used to prevent overflow if the primary drain line blocks.

Since p traps seal against air leakage they were the natural solution to prevent air leaking in the condensate drains of early 1900s air conditioning units. W c 1 2 in. I have a forced air furnace air handler in my basement with a standard a c unit condenser out side a c coil in the main supply truck about a couple inches over the furnace air handler. Three quarters of an inch is sufficient for up to 20 tons according to the imc unless the drain outlet size is larger than in ch use t able 307 2 2 for condensate pipe sizing.

I am not sure about code but the need for a trap will depend on design of a c system. It s similar to the trap under your kitchen or bathroom sink. Do you know the proper way to size a p trap on an hvac unit. That is why in the summer your car drips water.

Drain s 2015 imc 307 2 2 requires that an air conditioning condensate drain inside diameter should not be smaller than in ch and should not be smaller than the drain pan outlet diameter. A p trap serves a very important purpose on an a c unit. Condensate drain pan h 2 minimum sea level when condensate begins to drain off h fan inlet pressure in. All air conditioners have a special drain for.

The pull of the water to the drain has to exceed the sucking of the supply fan negative pressure rule of thumb add 2 5 to the static pressure before the fan return and internal to the unit and that s the long end. As air conditioning caught on in the 50s p traps were the standard that every contractor field designed and installed even if it was unknown to them whether the drain pan was at. The condensate line comes out of the main trunk and runs to the floor just above the drain near the furnace. Trap failures due to freeze up drying out breakage blockage and or improper installation can compromise the seal against air ingestion through the condensate drain line.