Common Problems in Connecting Two Wood Boilers Together (Part 2)

This Alternative Heating and Supplies tips, part two of outdoor wood boilers installations, and here we'll discuss the problems that I see with improperly installed plate exchangers and improperly installs on indoor boilers.

If you haven't installed your boiler yet, go back to Chapter 1 and learn how to install it properly.

 

 

I'm gonna go into the problems that I get all the time of people calling and saying, "Look, I'm having problems. My buddy told me to install it this way, my plumber did it this way, and I'm having problems." And I'm hoping that this video will solve a lot of those problems and those phone calls for people. Because unfortunately, it's gonna cost them a lot of money. Because basically what I tell them is what I told you in video Number 1 of this episode here, to basically undo everything and redo it, which costs a lot of time, a lot of money, and more parts, usually.

The Supply Side and The Return Side of an Outdoor Wood Boiler Heat Exchanger

So one of the most common problems is, as you saw in Chapter 1, I basically tell you, you never touch the supply side, it comes through, you break it into the return side.

 

Breaking the Main Truck Line

So it's gonna come in here and out here, and that's a basically the install. It's just that simple. But what most people do is they will look at the system, they won't think this out, and they say, "Wait a minute, I got a port here and a port here," because they're usually made out of black tees.

And sometimes, a lot of the plumbers add extra zones on, because they don't know if they're gonna add another zone or heating a garage or whatever. So there's actually sometimes extra zones that are just capped.

 

Alternative Installation

So the plumbers, or the people, the do-it-yourselfers will actually say, "Well, wait a minute, I got a zone right here, and I'll take this plate and I'll mount it right here." Okay. So what they'll do is they'll pull off this side, and they'll pull it in here, and then they'll pull it out of the heat exchanger and over to the return side. And then they'll put a circulator in there. And that's identified by a circle with a triangle if you're ever looking at a chart.

Water Temperatures

What's gonna happen? So let's say hypothetically the boiler is up to 175 degrees. So the water is gonna go up, and you've gotta remember, we got three other zones, plus this new zone, which is four, and the water is gonna come up into here, and it's gonna be sucked this way into the plate exchanger, which is being heated by the wood furnace. And the water's coming into this at 180, and come back out. So the water in here is hot. So it's gonna come in here and heat up.

So now it's heating up this water, which is already at 175 degrees. And as I told you in Chapter 1, you'll have about a six-degree delta T. So if the water is coming in at 180, the most you could ever get out of it is 175. So you're really not heating anything. So the water is circulating, and now it's dumping back into this manifold. But in this manifold, the water's leaving here at 175, going through these zones, coming back at 152, 145, 155. And now we're gonna add 175 from that new zone that we added, which is gonna give us 627. Now that there are 4 zones with these other temperatures coming back at 152, 155, 145, plus the 175, and you're gonna divide that by 4 now. And that's gonna give us a temperature being all mixed together. So 152 is coming in here, 145, 155, and now mixed with 175, they're all gonna come together and go down this main pipe at 156 degrees. That's if all zones are firing. That's gonna go back into the boiler.

 

Average Temperature Return in Alternative Installation

Now it's in here at 156. And let's say it's still running. So the water is gonna go through again, and roughly, you're losing 20 degrees in these zones. So it's gonna go out 156. It's not gonna go through this plate exchanger, and it's gonna be heated back up to roughly, let's say 175. That means your boiler will never exceed 156, and it will slowly, but surely, start to lose its core temperature. No matter what you do, you cannot have three zones against one and expect it to keep up.

A lot of people will do it this way and have a lot of excess for the first couple years. The reasons why: the plate exchanger is extremely clean, the flow rates are beautifully high, the surface area in there, you're not having any rust or corrosion or buildup on the plate exchangers. The pumps are running at full capacity, gallons per minute flows are maxed out. Just like you know, everything over time starts to weaken and slow down a little bit.

Also, the efficiencies of your home are dropping off, referring that the house is settling the cracks and the insulation starts to diminish a little bit, that's why older homes have very poor insulation. When they were built, they weren't that bad, that's why this is happening.

Problems that May Appear a Few Years After the Installation

Knowing How to Connect a Boiler to a Boiler

So this is one of the main culprits of why people call me a couple years after they've installed because they saw their buddy do it. Another very big problem is that they talk to people who don't know how to connect a boiler to a boiler. Now, there's a lot of plumbers out there that know the inside of a boiler and how to install the boiler aspect beautifully, and there's no problem with that. But when you ask them how to make a boiler work with another boiler, most plumbers, and not all of them, have a very difficult time understanding the concept, and they will find this…and also, a lot of homeowners will see this as the simplest way to install it when, actually, I find it one of the hardest ways to install it, because now you're breaking into two zones or the supply and return of a boiler.

Losing Heat

Now, here's the other problem and where people also lose heat, is if the plumber designed the system to have 6 counts per minute going through each zone, so 18 gallons a minute and this zone, water will travel the easiest path, and especially with the pump, and it's a very short loop.

So if this was designed to run at six or eight gallons a minute, which is an average loop, now you're only sending four, maybe six gallons of water through these zones, okay, which is weakening these zones. So instead of it taking 20, 30 minutes for that zone to heat up, now it's taking 40, 45 minutes. And again, if you're losing the core temperature of 56, that temperature loss is gonna make that zone run even longer. And eventually, it will never keep up, and that's the problem. And you'll find certain parts of your house getting colder, that's another reason. And that's the reason why that's happening.

Pump Sizing

Another problem that seems to be a big problem is, on top of the installation aspect of where it is, is the pump sizing. A lot of manufacturers will actually say, "Hey, we're gonna sell you a pump, and the pump comes free with the stove."

Well, how is a pump sized for its application? Every application is different. Are you gonna put it 50 feet away or 150 feet away? It's all different. So having a generalized pump does not solve the problem. So if it's installed in the first or second alternative, the pump gallons-per-minute flow is very important.

Now, we here at Alternative Heating know this, because we've been doing this for 14 years, de-sizing pumps to outdoor boiler applications, so it's very simple for us.

And actually, there's a video that I have put out on pumps and give you some general concepts of what pumps to use based on your distances and applications

But you're always welcome to give us a call, and we'll size the pump for you. And we can only size the pumps that we know, which we sell. Now, if you're calling us about different pumps that we that we don't know about or don't carry, we don't know the answers. And the pumps that I sell are made specifically for this application. It's the only reason I carry these pumps.

Water Flow

How many gallons per minute flow should you have going back and forth to your outdoor wood boiler? The answer to that question is, anywhere from 8 to 12.

Now, how are you gonna determine how many gallons per minute flow you have going back and forth, is a very difficult thing, and very expensive if you have the tools or the parts to determine that. But the best way to do it, if you're really, really eager to know, is you're gonna have to cut the return line.

And basically, you turn on your pump, fill up your wood boiler as high as it'll go, put that into a five-gallon bucket, get two or three of them there, set your stopwatch, see how fast you fill up those buckets and how many buckets you fill up within one minute, gallons per minute.

So if you fill up 10 gallons or two 5-gallon buckets in 1 minute, you're running 10 gallons per minute flow. That's just a general way of finding it, but it gets you in the ballpark, not absolutely necessary. If you ask us to size the pumps, we're usually gonna nail it right on the head anyway, it's always in. When we size them, we always try to nail it between 8 to 12. And in our case, we just use 14 years of experience, and this is all we do for a living, of hooking up outdoor wood boilers to indoor heating systems. So that's how we got our expertise.

So a lot of these problems can be fixed very rapidly and easily unless it's installed in the incorrect place. If it's installed like the second option, my suggestion is, undo it, go back to video Number 1, and redo it this way.

You'll notice that you're not running a core temperature of 156 anymore, you'll be up in the 170 to 175 range, your wife will be happy, you'll have endless hot water, and everything will be good. And that's really it. Now this also, these zones, also apply to boiler mates and everything.

 

Boilermate

And here's my last favorite saying I say to everybody that's installing these boilers, all the return zones, all of them, if you have a boilermate that and it's tied back in here, all the return zones must go through the plate exchanger before returning to the boiler. As long as you follow that basic line, all the return zones must go through the plate exchanger before returning to the boiler, and your system will run beautifully.

 

The Return Zones Going Through the Plate Exchanger

That's really all I have for you, and if it's not done that way, I recommend you do it that way. If you have anything besides what I've shown here, there are hundreds of variables, but please go back to this. This will solve your problem 99% of the time. And if it doesn't, feel free to call us, we're here to help you, and let us know.

Let us know what you think in the comments and contact us! I can't fix everybody's problem via the phone, but I can guide you to the parts and things that you might need for those heating systems.