Archive for December, 2009
There are many different types of valves for different applications, so how do you know which is the best to use for your application? We’ll start by looking at globe valves and ball valves. The main difference between these two types is the way they close. A globe valve uses a plug (stem) that closes against the flow, and a ball valve has a gate (ball) that closes across the flow. Globe valves are good for regulating flow, whereas ball valves are better for on/off control without pressure drop.
For many decades globe valves were considered the industry standard in control valves. They are designed with a stem that moves up and down inside the valve to control flow. They are commonly used on hot and chill water coils, and larger models are often used to control flow to chillers. One of the main limitations of globe valves is that their close-off rating can be lower than other valves, especially in the larger sizes.
Ball valves are designed with a ball inside the valve. The ball has a hole through the middle so that when the hole is in line with both ends of the valve, flow will occur. When the valve is closed by turning the ball 90 degrees, the hole is perpendicular to the ends of the valve, and therefore flow is blocked. Ball valves are very durable and usually have excellent shutoff even after years of use. They are generally preferred over globe valves in shutoff applications. The main limitation for ball valves is proportional control because of the large amount of flow that the ball allows.
Check back soon for more valve comparisons. Up next, 2-way vs. 3-way valves. Until then, I hope everyone has a Happy New Year!
Check out Sophia Bellos as she shows us why Honeywell’s direct coupled actuators are a great choice. Sophia demonstrates unique features that save time and money on valve and damper installations including Honeywell’s new Zelix Actuator.
Stromquist & Companykeeps a large inventory of these products in our Atlanta and Florida locations so if you are a Stromquist customer or are located in Georgia or Florida call today for a free catalog. Others can contact one of our affiliates at Controls Group North America.
- Determine the throttling range for your control system. Let’s use 3-13#’s as an example.
- Next measure the ambient temperature at the thermostat with a precision temp meter.
- Adjust the setpoint knob on the T Stat to the current ambient temperature.
- Pull the branch line off the T-Stat and T tap a gauge between the T-stat and branch line.
- Adjust the calibration screw in the T-Stat until the branch PSI reads zero.
- Now adjust the calibration screw in the opposite direction until the branch pressure reads mid range. In this case our differential is 10#’s of pressure, so (13-3)= 10(diff) /2 or 3+5 = 8 psi.
- Verify the box damper and reheat valve(if applicable) are both closed. Fine tune if needed.
- Remove your calibration gauge and replace the branch line back onto the T-Stat.
- Adjust the T-Stat to the desired setpoint.
Your T-Stat is now calibrated…
You can’t get heat and your troubleshooting skills (hopefully learned at a Stromquist & Company training class) have lead you to the conclusion that your gas valve will have to be replaced. Being the great technician that you are, you write down all the information and part numbers of the furnace or heater you are working on and head off to see Bob, Jerry, or Mark at the Stromquist counter to get a new valve.
After driving across town you are less than happy when you are told that the replacement gas valve cannot be determined by the furnace or heater number. Although there are hundreds of gas heater and furnace manufacturers, there are only three major controls companies that make gas valves for these companies: Honeywell, White Rodgers, and Robertshaw. What makes it tricky is that these three companies will make and sell these valves as OEM (original equipment manufacturer) parts for all these different heater companies and will put different part numbers on them. In some cases, the valves even function differently.
Why would a manufacturer want a different part number? For one thing it makes it very difficult for you to get a replacement valve at your local distributor. Think about it, these companies are in business to make money and if you have to come back to them for your replacement parts, they are able to sell more products. The problem with this is that very few of them have local inventory, and since they are manufacturers instead of wholesalers, quick shipping is usually not one of their skill sets. So you have to wait, which is usually not an option when your heat is not working. In a few cases the valve is built differently and you have no choice but to go back to the manufacturer, which usually results in you paying higher prices and dealing with longer lead times.
The good news is that with the right information, your local distributors like Stromquist & Company can provide you with the right gas valve at the right price. To make sure you get the right valve, either take the bad valve out and bring it into your local distributor or use your camera and take pictures of the valve, making sure to get the part numbers in the picture. Make sure to watch Mark’s video, Replacing Gas Valves On Furnances and Hot Water Heaters.
I think we would all be a little frustrated if we had to use a separate radio for each station we listen to. Before open protocol architecture, this scenario is similar to what end users of DDC systems had to do. It wasn’t uncommon to walk into an engineer’s office and see an array of monitors spread across the desk. Not only was this unsightly, it was expensive to maintain. As time went on, the attempt to solve this problem with custom drivers that could talk to proprietary systems failed miserably. It was messy and costly to reverse engineer, and the manufacturer would make changes that would break these bridges to freedom. In addition, once an equipment manufacturer was in the building with their product, it was next to impossible to get them out. Thus began the true motivation behind an open protocol.
By its most general definition, open protocol is the property of public domain. This means that there is no physical ownership, and it’s free for anyone who wants to develop it. To achieve success in such an open standard would require not only a free-for-all mentality, but also a robust, intuitive and flexible approach to building automation solutions.
Over the next several posts I will dive into what types of open protocols the industry has to offer. We will look at their strengths and weaknesses and talk about what the future has in store for open communications within the building automation industry.
It is the holiday season, and it has been a tough year for all of us. We all share common goals and activities in this industry and that makes us a family. As a family, we at Stromquist and Company would like to wish all of our family members all the warmth and happiness that this holiday season can bestow upon you.
The time we take to remember someone who is or has been special in our lives will help melt away all the problems we may have experienced during this past year and will prepare us for the New Year with a renewed feeling of hope.
To all the friends and family of Stromquist and Company our thanks and gratitude go out to you for the past year and the years to come.
Our newest employee, Paul Morin, recently conducted a training class on installations and terminations. Before coming to work for Stromquist, Paul worked in HVAC contracting so he knows a lot about the industry. He is a very sharp guy and a great teacher. His class covered methods of wiring, different types of wiring and cables, VAV box schedules, mechanical drawings and much more. After the class, those in attendance said it was very beneficial and that they really learned a lot from it. One attendee said that what he learned in the class will definitely help him on future installations and wiring. The class was received so well that we are going to have Paul teach it again after the first of the year. We will post more information on it when we get it scheduled, so be on the lookout and plan to attend if you’re in the Atlanta area.
There are hundreds of furnace and heater manufacturers out there, yet there are only three main companies that make the gas valves for all these heaters. The companies that make the gas valves usually put a different part number on the valves for each of these heater companies. This makes finding the right replacement valve tricky.
Although you can go back to the manufacturer to buy replacement parts using the part number of the heater, you usually wind up paying a lot more for the valve and will have a hard time getting the valve shipped quickly.
The best choice is going to a local wholesaler like Stromquist & Company, or another company within CGNA ( Controls Group North America).
When you go to the local wholesaler don’t make the same mistake most people do. Most people take the part number off of the furnace, but we need the number off of the gas valve itself. In this video, Mark from Stromquist & Company will show you where it is.
The latest accurate information and demos on products
