W1, W2, & E
I got this question via email (edited slightly for length): Some things I've done because I've been taught to do them yet I don't know why I do them. One of those things is putting a jumper between w1/e and w2. Sometimes, in the case of a Goodman for example, I've been taught to combine […]
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Modulation Motors
Modulation motors are not often seen in residential equipment, but we see them a lot in commercial and industrial applications on many different types of equipment. I see them primarily on larger burners to control the fuel firing rate, but they also control water flow through heating coils, the water level on cooling towers, and […]
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The Good Old Heat Anticipator
As a technician, you most likely know some customers who still have an oldie thermostat (you know, those old mercury bulb things, like the round Honeywell CT87 and such). Keep in mind that those usually have an adjustable heat anticipator. If you’re newer in the field, you may not have seen or worked with those […]
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4-20ma Control Basics
Back in the “good old days,” controls were all analog and mechanical, which simply means that they acted in a directly connected and variable manner based on a change in force. Both pneumatic (air pressure) or hydraulic (fluid pressure) systems are examples of mechanical or analog controls. When the pressure increased or decreased on a […]
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Commercial Contactor Considerations
This tip was created by Jason Pinzak and originally posted on the HVAC Technician's Facebook group. It is reposted here with permission from Jason. Thanks! Contactors are useful in commercial and industrial applications, particularly for controlling large lighting loads and motors. One of their hallmarks is reliability. However, like any other device, they are not […]
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