They have one inlet...sometimes. Sometimes they have two.

They have one outlet...sometimes. Sometimes they have two.
                        Well now, that's clear as mud.

Ok, the porting (inlets and outlets in laymen's terms) is determined by what type of three way valve it is; either a mixing valve, or a diverting valve.
Mixing valves have two inlets and one outlet. Diverting valves have one inlet, and two outlets.

The common port is normally marked AB, and the other two ports are marked A and B.
Either valve can be used to vary either flow or temperature, depending on how its piped.

As with a two way valve, the three way valve generally shuts off against the direction of flow to stop water hammer and allow smoother control.
And I almost forgot; they're either open, closed, or somewhere in between.

Next article we'll talk about how to pipe them.

Here's the basics on two way valves-

• They have one inlet and one outlet.
• They're either open, closed, or somewhere in between.

As far as the internals go; some are single seat, others are double seat. Some are globe, some are ball, some are gate, and some are butterfly.
Here's what you need to know about them-
They need to be piped correctly meaning, the inlet needs to be the inlet, and the outlet needs to be the outlet. They generally (almost always) close against the flow of water to prevent water hammer caused by water pressure slamming the valve shut. This is especially important with single seated valves.

What’s to know about valves? They’re either open, or they’re closed. Right?

Fact is, there’s a lot to know about valves, and being valve savvy is one of the things that makes a master technician.

What are valves used for in our industry?  You name it, valves are used to control it:

• Steam for heating
• Steam for humidification
• Hot water
• Chilled water
• Condenser (cooling tower) water

How many kinds of valves are there? Let’s see, five….plus a few variations.

• Two way
• Three way Mixing
• Three way Diverting
• Modulating
• Non modulating

In the next few articles we’ll talk about porting and piping, applications and of course, troubleshooting.

                                                                                     Stay Tuned

How many times have you run across this one-
The home owner calls and complains of water dripping from the ceiling diffusers, but it only happens in the winter, and it's an A/C system. You go to the home, look at the system, and find the ductwork and air handler sopping wet. What's up with that?
Here's the low down.
This is a common occurrence in homes with separate heating and cooling systems, like baseboard hot water, steam, or radiant floor for heating, and an air handler in the attic for cooling.
OK, so now the big question- Why?
During the summer the air handler is running in cooling; there's 50 degree (give or take a few degrees) air in the supply duct, and 80 (give or take a few degrees) degree air in the return duct, and it's all surrounded by 100 degree air (give or take a few degrees).
In this situation everything is fine, you may have some condensation on the outside of the duct work, but only if the insulation is ripped or too thin.
Now comes the heating season.
Now, the air surrounding the ductwork is colder than the air inside the duct.
The warm air in the space rises into the cold ductwork and air handler. Why? Because hot always travels to cold. The warm humid air from the living space hits the nice cold ductwork and air handler and guess what happens next.
You know how condensation forms on a cold beer can on a hot summer day? The temperature of the can is below the dew point of the air, causing condensation to form, Well, the same thing happens in your duct work and air handler, only it happens on the inside of your duct work.
Now we know why it happens, the next question is- how do we stop it?

You can't, you're hosed.

Just kidding. You have two options: stop the air from entering the ductwork, or keep the ductwork and air handler temperature above the air's dew point. You can try blocking the air flow by sealing the vents or wrapping the filter in a plastic bag (do not forget to remove the covers / wrapping before running the A/C come summer!)
The other option? Run the air handler fan at a low speed, or at 20 minute intervals during the winter using a timer; this will keep the ductwork and air handler temperature above dew point.

The folks at Total Performance Diagnostics asked us if we would like to take their system diagnostic program for a test ride. What was our response? 'Heck Yea!'

So, they tossed us the keys, and off we went. We took it for a spin by throwing a few system operational readings at it and checking the results.

And what did we think of it? It rocks!

In a nut shell-The program is user friendly and provides an easy to understand, detailed system report. It' understandable why it won the Bronze Dealer Design Award for 2012. 

Keep in mind, I'm against the "dumbing down" of our profession (or any profession for that matter) and personally feel that technicians need to understand how to troubleshoot systems using their noggin.

That being said; there have been times (quite a few times) that a problem stumped me, and having a diagnostic tool like this would likely have pulled my butt out of the proverbial flames.

Something I really like about this program; you still need to know how to take operational readings, that helps keep the dumb-down factor low.

Another reason I like this tool; It's provides proof to the customer (and you) that your diagnosis and repair are correct.
I would definitely recommend adding this to your arsenal of diagnostic (and sales) tools.

Patrick