This is another episode of Alternative Heating & Supplies' tips and in this blog post, we are going to talk about the tube and shell heating exchangers that are mounted on the side of domestic hot water tanks. We get a lotta phone calls from people who have purchased sidearms from other companies and even our own company and they don't have it working properly because of simple mistakes.
So the most common way to install them is to mount them off the side of the domestic hot water tank. Let's further see how.
Sidearm and Tube and Shell Heating Exchangers
Shell & Tube heat exchangers are suited for higher-pressure applications. As its name implies, this type of heat exchanger consists of a shell (a large pressure vessel) with a bundle of tubes inside it.
One fluid runs through the tubes, and another fluid flows over the tubes (through the shell) to transfer heat between the two fluids. Ideal for many residential and industrial applications. Their complete stainless steel welded structure ensures product strength and high-quality performance.
Applications: Pools, spas, hot tubs, transmission and engine coolers, oil coolers, boiler sample cooler, waste water heat recovery.
Sidearm and the Tube & Shell Heating Exchanger
Sidearm Heat Exchanger Installation Guide
How Do Heat Exchangers Work
The way they work is that they gonna heat up the water inside the domestic hot water tank, the coldest water's gonna drop to the bottom, which is going to pour into the bottom of the sidearm of the side arm heat exchanger. As the water from the outside boiler comes into the tube and shell, it's gonna heat up the domestic water, and as the water heats up, it rises.
So the domestic hot water's gonna rise up and then go straight into the tank, and then the coldest water in the tank is gonna drop to the bottom and it's gonna be heated up again, and this convection system will go on and on to keep the tank up to a reasonable temperature where everybody's happy.
You're not running a pump, you're not doing anything, just the convection of the hot water coming in from the boiler and the natural convection of the domestic hot water tank is gonna give you all the hot water you'll ever need.
Causes of Heat Exchanger Failures
Where the problem comes is that most people who have the problems, they will not install the sidearm heat exchangers. You see here at the bottom the water comes out of the tank and drops. That's what cold water does, the coldest water drops. But as it heats up, it rises. And where the mistake is usually done is right here.
Thermal Blocks and Convection Systems
Most of the people will actually bring it up, bring it over, and then drop it back into the tank here. The problem is how water rises, it doesn't drop, you just created a thermal block. When you create a thermal block, the only way that hot water will drop, is when it cools off and the water will cool off, that means you're not gonna get a convection system. The water has to go back straight but it cannot drop. When you do that, that's called a thermal block. You can't have that. So you need to install it this way.
Heat Exchanger Pots
A lot of people have a problem where they don't have these side ports on the side of their tanks, but most of the tanks that are purchased today, they always have a pressure relief valve and they also have a drain at the very bottom which you can see at the bottom underneath this one. This tank does have the hot and cold inserts on the side. So if you didn't have these two pots that I have mounted to, you can pull off the drain, put it in like you see here, and then take the pressure relief valve, tee it off, put a tee here, put the pressure leaf off one side, and the top of the side arm goes in the other side because it's still gonna be flat, and the water will rise and go in there.
So that's the best way to install this tube and shell heat exchanger. And if it's done like this, you will have no problems, the convection system will work beautifully. Now if you don't have these ports, the pressure relief port or the drain at the bottom which you'll always have a drain, but sometimes the pressure reliefs are done on the back side or on top.
The Plate Exchanger
Okay, if you have this, then we're gonna recommend you go to the plate exchanger, which is another easy install, actually a little bit more simplified, and that works on a thermal pressure syphon, which I'll go on to explain deeper in the next video that I have, and it's called "Plates Exchangers For Domestic Hot Water Tanks."
Material Selection for Shell and Tube Heat Exchanger
When installing the tube and shell heat exchanger, you can use a couple of different materials.
- You can use PEX which is seen here, but you can use it here. PEX is not recommended because once PEX heats up, it gets kind of flexible and it's not gonna hold up very well, it'll look sloppy.
- In this case, I use a lead-free brass. It's what I carry and it's easily and readily available for me, so that's what I have done here. And you can see the install came out just fine.
- The other option is a good grade copper. The copper you can solder, thread, and dope, if you would like.
You have to remember that this tank is under a lotta pressure, so when you're especially doing the domestic hot water side, I recommend that you use unions, so if there's ever a leak or any kind of adjustment or anything else you do, you can take it on and off pretty simply.
Make sure you're using Teflon and a domestic hot water rated Teflon and copper dope because you don't wanna have a dope that is not good because that's gonna end up in your drinking water or the water you bathe with, and a very small amount, but again, make sure it's used for potable water.
Heat Exchanger Case Study
Jay Is a Hardworking person who was raised heating his families home with wood. Know he can provide it to his family with a lot less work and effort.
Heat Exchanger Installation
The Heat exchanger fit nicely into plenum of his hot air furnace. Or Hot Air Kit
I’m hooking up the hot water heater. This is a Ten Plate water to water heat exchanger. Or see Domestic Hot Water kits.
Ten Plate Water to Water Heat Exchanger.
You can see how we came through the wall. We measured wrong and need to fill one hole. Measure twice drill once!
Water Heat Exchanger Hooked Up
Completed water to water heat exchanger hooked up and running.
Water to Hot Air Furnace
Completed water to hot air furnace hook up.
Water to Hot Air Furnace
Another angle so you can see how easy it really is.
And these are the installation steps for the tube and shell heat exchanger and water to water heat exchanger. If you guys have any questions or comments, please leave a comment on the YouTube video, we'd love to have your inputs, we'd love to hear your suggestions.
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