I have an old Grindmaster Espressimo that I have been refurbishing. Out of the blue the heating element started acting funny.  It arced and melted, so I replaced it, but the new one is also running hot.  The plastic on the top around the terminals actually melted away. Any ideas as to what could be causing this? The wattage is the same as the previous two I have had in there, and slightly less than factory.  I checked the connections and they are tight.

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Not enough water in the boiler to cover the element?
Dry fry is what caused a couple of previous heating elements to go out, the fill line to the boiler got clogged. This time however there is plenty of water - up to the float.

Phil Proteau said:
Not enough water in the boiler to cover the element?
Can you take a picture of what melted? It's hard for a boiler to get that hot with water in it. Did it produce steam before the damage?

Chris Hooton said:
Dry fry is what caused a couple of previous heating elements to go out, the fill line to the boiler got clogged. This time however there is plenty of water - up to the float.

Phil Proteau said:
Not enough water in the boiler to cover the element?

This is basically the element in the machine. You'll notice the black plastic where the terminals are. That has completely melted away. As of now, this element is still functioning. I get steam, and the shots I pull indicate that the brew temp is too high. I can pull it down with the p-stat, but that doesn't solve the problem - that the terminals get hot enough while the element is powered to melt plastic. There has to be more going on than fine tuning the pressure-stat. I have gone over the wires and haven't found any irregularities by sight. One of the spade terminals was corroded. I replaced that hoping to solve the problem, but it is till running too hot. It seems that something is causing the external terminals to have enough resistance to act like a heating element themselves, but I haven't found it. I'll attach the pdf with the wiring schematics if it will help...
Attachments:
How would a bad switch contribute? What should I look for there?

Mitchell Schuur said:
Check the electric system, might be a bad switch or molten resistance....
So the element drops down vertically into the tank? How do you know that it's currently overheating?
It really seems like it can only be one of 2 things. Your p-stat is broken or not adjusted or there is not enough water in the tank. Since it appears that the element hangs down, it would seem that that at least a couple inches of the element, near the base, would not be exposed to water and would cause it to be hotter in that area (near the plastic base).

The element you showed a picture of is not bent like the one is in the parts diagram. Is it possible you have the wrong element? A longer element would keep the hotter section submerged, cooling it.

Chris Hooton said:

This is basically the element in the machine. You'll notice the black plastic where the terminals are. That has completely melted away. As of now, this element is still functioning. I get steam, and the shots I pull indicate that the brew temp is too high. I can pull it down with the p-stat, but that doesn't solve the problem - that the terminals get hot enough while the element is powered to melt plastic. There has to be more going on than fine tuning the pressure-stat. I have gone over the wires and haven't found any irregularities by sight. One of the spade terminals was corroded. I replaced that hoping to solve the problem, but it is till running too hot. It seems that something is causing the external terminals to have enough resistance to act like a heating element themselves, but I haven't found it. I'll attach the pdf with the wiring schematics if it will help...
Wes, that is a good point. I am not using factory parts, they stopped making this thing a while back and prices for the parts from grandmaster are crazy. It takes a regular water heater element. They do seem to be getting shorter - a higher wattage density, so a longer one might ease the situation. Still, though, for this to just start becoming an issue is baffling.

I've been thinking about the p-stat - it seems that in adjusting it, it is all or nothing. I may have to replace that. Still that only controls how long the element is on, not how hot it gets while it is on.

Wes Russell said:
So the element drops down vertically into the tank? How do you know that it's currently overheating?
It really seems like it can only be one of 2 things. Your p-stat is broken or not adjusted or there is not enough water in the tank. Since it appears that the element hangs down, it would seem that that at least a couple inches of the element, near the base, would not be exposed to water and would cause it to be hotter in that area (near the plastic base). The element you showed a picture of is not bent like the one is in the parts diagram. Is it possible you have the wrong element? A longer element would keep the hotter section submerged, cooling it.
I'll have to do some research then and see what kind of resistance is normal and then poke around with my multimeter.

Mitchell Schuur said:
Could be, I'm not saying it is, but if there's a problem with one, or more, switch or resistance or whatever in the system, it could overload some parts. maybe the resistance is gone and the heating element gets too much power so it overheats.... Had it with my ECM, the motherboard was partially melted which caused the machine to pull shots at 11 bar instead of 9....so
So I think that's your tip off. Higher wattage density is putting more wattage above the water line which can then travel up into the plastic base in the form of heat. Can you get a longer one and bend it to shape?



Chris Hooton said:
Wes, that is a good point. I am not using factory parts, they stopped making this thing a while back and prices for the parts from grandmaster are crazy. It takes a regular water heater element. They do seem to be getting shorter - a higher wattage density, so a longer one might ease the situation. Still, though, for this to just start becoming an issue is baffling.

I've been thinking about the p-stat - it seems that in adjusting it, it is all or nothing. I may have to replace that. Still that only controls how long the element is on, not how hot it gets while it is on.

Wes Russell said:
So the element drops down vertically into the tank? How do you know that it's currently overheating?
It really seems like it can only be one of 2 things. Your p-stat is broken or not adjusted or there is not enough water in the tank. Since it appears that the element hangs down, it would seem that that at least a couple inches of the element, near the base, would not be exposed to water and would cause it to be hotter in that area (near the plastic base). The element you showed a picture of is not bent like the one is in the parts diagram. Is it possible you have the wrong element? A longer element would keep the hotter section submerged, cooling it.
can you do that (bending) while preserving continuity? I was playing around with an ohms law calculator. It looks like I could get a 240v 4500w low density element and running it at 120v would produce around 1500w. I might be able to find one of those.

Wes Russell said:
So I think that's your tip off. Higher wattage density is putting more wattage above the water line which can then travel up into the plastic base in the form of heat. Can you get a longer one and bend it to shape?



Chris Hooton said:
Wes, that is a good point. I am not using factory parts, they stopped making this thing a while back and prices for the parts from grandmaster are crazy. It takes a regular water heater element. They do seem to be getting shorter - a higher wattage density, so a longer one might ease the situation. Still, though, for this to just start becoming an issue is baffling.

I've been thinking about the p-stat - it seems that in adjusting it, it is all or nothing. I may have to replace that. Still that only controls how long the element is on, not how hot it gets while it is on.

Wes Russell said:
So the element drops down vertically into the tank? How do you know that it's currently overheating?
It really seems like it can only be one of 2 things. Your p-stat is broken or not adjusted or there is not enough water in the tank. Since it appears that the element hangs down, it would seem that that at least a couple inches of the element, near the base, would not be exposed to water and would cause it to be hotter in that area (near the plastic base). The element you showed a picture of is not bent like the one is in the parts diagram. Is it possible you have the wrong element? A longer element would keep the hotter section submerged, cooling it.
One thing to keep in mind is that you are really reengineering your machine which could lead to some dangerous results. What if that plastic cap melted through? The element you are using might be designed to be fully submerged. The base of the original part, while being the same size may have been made of a heat resistant material.
My advice would be to get the original part. Good luck!

Chris Hooton said:
can you do that (bending) while preserving continuity? I was playing around with an ohms law calculator. It looks like I could get a 240v 4500w low density element and running it at 120v would produce around 1500w. I might be able to find one of those.

Wes Russell said:
So I think that's your tip off. Higher wattage density is putting more wattage above the water line which can then travel up into the plastic base in the form of heat. Can you get a longer one and bend it to shape?



Chris Hooton said:
Wes, that is a good point. I am not using factory parts, they stopped making this thing a while back and prices for the parts from grandmaster are crazy. It takes a regular water heater element. They do seem to be getting shorter - a higher wattage density, so a longer one might ease the situation. Still, though, for this to just start becoming an issue is baffling.

I've been thinking about the p-stat - it seems that in adjusting it, it is all or nothing. I may have to replace that. Still that only controls how long the element is on, not how hot it gets while it is on.

Wes Russell said:
So the element drops down vertically into the tank? How do you know that it's currently overheating?
It really seems like it can only be one of 2 things. Your p-stat is broken or not adjusted or there is not enough water in the tank. Since it appears that the element hangs down, it would seem that that at least a couple inches of the element, near the base, would not be exposed to water and would cause it to be hotter in that area (near the plastic base). The element you showed a picture of is not bent like the one is in the parts diagram. Is it possible you have the wrong element? A longer element would keep the hotter section submerged, cooling it.

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