This article was written by HVAC contractor and Building Science Whiz, Michael Housh. Thanks, Michael! For a while, I’ve fallen into this camp where I feel Manual J overshoots heating loads. First off, I would like to say that Manual J is only as good as the information you give it, but we often run […]

Go to your truck, pick up a contactor, and look at it closely. You may find some interesting ratings you never noticed—things like terminal ambient temperature ratings and torque specs. One reading you may overlook is the RES AMPACITY of the contactor or relay. The RES rating is the RESISTIVE LOAD AMPACITY (amperage capacity) or rating. […]

See the photo above? This is a unit we (my company) serviced for a commercial customer. It doesn't matter if we aligned the belt, dialed in the charge, cleaned the condenser (using THIS thorough process), and got the drain pan clean. We look like dummies because the panel fell off. Also, as you may notice, […]