How to Restring a Heat Strip
If you've got a couple of heater kits where you've taken air handlers out on your property, take the heat strips out. If they're bad, we can go ahead and resr them, have them ready to go. So if we do get an emergency heat call. We don't necessarily have to be fumbling to string this up. It's already strung, ready to go.
Take the new one, put it in your service request is over, especially if it's an emergency after hours. Then the next day when you go in, throughout your travels in a day, you can retr another kit. But that's what this video's all about. Have to retr a heater kit.
Most technicians want a quick, easy way to repair and replace. So they'll have heater kits that they can buy separately, but they're usually anywhere from 80 to $120, depending on the brand, the type, or anything like that. So if we know how to restrain these kits cost you $10 or less. So what I'm gonna show you and where I made my mistakes when I was in the field is trying to restrain these by a heater kit, and ultimately they failed because I didn't understand how to restrain them.
And once I was shown once, then it was easy after that. I am gonna assume that we've already diagnosed the heater to get to this point. So you've assumed that there's power, the heating controls. Heat relays are all sending the signal, but for some reason the unit is not producing the heat. We have two safety controls and any electric strip heat, one is a fusible link, can be the type that wire in like this or can be in line.
To the heater itself. Then we have a high limit switch that also shuts out. So when we're testing these, we wanna make sure our safety devices have not tripped or blown. If they have, we need to identify the problem that has blown them. So when testing the element for complete circuits or continuity, we can go to one side to the other side.
That tells me I have a complete circuit. If I didn't have a complete circuit in this one here, we have a fusible link. So to test the fusible length, the strip would have to be removed, one lead on each side of the Fusible link. From here to here, that tells me that the device here is solid and I can go ahead and assume that the reason I'm not getting continuity and what's gonna happen is if I have a heat strip that has burnt into.
Now when I go to test this circuit, I get nothing. If I test the fusible link to identify, to make sure it's not bad. I do have continuity on each side of the Fusible link, but usually during a visual inspection, when you pull it out, you're going to see the break. So now what you want to do is make sure that you carefully remove it.
When I was in the field years ago, the first one I did, I just started ripping it out as fast as I could, and this will be your template for the new strip that you're going to
install.
So you have the two pieces
of the strip, not overstretched. So now I'm going to try to put them or splice them back into one another.
And you just screw it into it till it holds or grabbed. So now I have a template of my new strip, and this is where you're either gonna need a bench vice. Or another hand, and in this case I'm gonna use another hand. So now what I wanna do is I want to get my heat strip that is rated for this particular item.
And this is a five kw and I have a five day KW heat strip. So now this strip. Needs to be stretched to that size before, what I would do is I'd try to put it in here and stretch it as I went. So I don't really need to do that. What I need to do is be able to stretch this exactly the length, and if you'll notice, each one of these circles or cues are stretched perfectly.
They're not overstretched in places. So when I would try to string these in there. I would overstretch in a place which would cause more stress, give it more heat, and ultimately it would burn back into directly after I applied power.
So you have to stretch the new strip to the length of the old strip. So you can either take both of these and put 'em in a venge by so you've got one hand to pull on and be able to do it and hold it in place because you won't be able to stretch it out evenly in this case. I'm gonna use my lovely assistance's hand to grab the other side.
They're going to hold that while this other one is now stretched and you wanna pull it four or five times until the end length in reached to the point of the exact same size as the other one. So now I've got the size of my strip and now we compare. How evenly it stretched versus trying to stretch this the whole way.
So now I can discard this, and now I can rethread my heat kit back into the strip itself and it's cut. So now you want to thread this in the opposite way. So the center of my strip is going to go here, so I wanna start at each end and thread back through.
This takes a little bit of time.
The time to not do this. Is during a maintenance emergency with no heat, have these res strung ready to go so that way you're just repairing the whole assembly. Most of us have a couple of assemblies that need to be repaired, need to be done, and it's nice to have these already strung up.
It does take a little bit of time to thread this through here to get it stretched out and get it in, but as you can see, for less than $10, I have a new heat strip ready to go. New fuse links. New high limit switches, and now I feel comfortable putting this back in and ready to go rather than spending anywhere from 80 to $120, depending on the heat kit that you have to have.
No, I did continuity. I did not do resistance. And that's what builds up the heat is resistance. Not continuity, but continuity tells me if the circuit's complete. So that's what get me to changing the element. So when I'm testing it, what I like to do is if I have a new one, and I know the specs. When I first tested this element, it was 11 ohms of resistance, and now it's fluctuating between 10.9.
10.6, 10.7 11 ohms of resistance. So I basically have the exact same kit with the exact same amount of resistance, and if I take the exact same voltage, I'm gonna get the exact number of heat BTUs from this strip based on numbers and the electrical characteristics.
