P Trap Hvac Condensate Drain Line Design

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.

P trap hvac condensate drain line design.

It s similar to the trap under your kitchen or bathroom sink. Minimum maximum sea level. Co ndes at r i p r ec om ndati. Do you know the proper way to size a p trap on an hvac unit.

A p trap serves a very important purpose on an a c unit. 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. All air conditioners have a special drain for. W c 1 2 in.

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. Condensate drain pan h 2 minimum sea level when condensate begins to drain off h fan inlet pressure in. Trap for draw thru unit condensate beginning to drain away. 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.

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. What is a p trap you say. A central air system routes condensation through a u shaped trap located in the drain line just outside the air handler. That is why in the summer your car drips water.

Fan inlet pressure negative h figure 3. Minimum h fan outlet pressure in. 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. 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.

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.