Voltage at Element but No Heat

[KEG99]

I think I blew my SSR in the middle of a brew. So I wired past the SSR and direct wired the element to finish up the brew. But no heat and no amperage draw. Checked circuits and have 120 v on each leg going direct to the element.

Replaced the element with a new one and still no heat and no amperage, but 240v (120v each leg) going to the element. Checked the old element and it read 12 ohms resistance as it should.

My question is, if I have voltage at the element, what other factor could make it not heat up, i.e. not take amperage, not draw power?

 

[sandyeggoxj]

So when you measure the VAC at the element across both hots you get 240vac? Do you have a known working element to swap in? You said you swapped it but was it known to be good? SSRs usually fail closed anyway which would be like wiring the element direct. Do you have an ammeter to measure current draw when the element is running? How did you check for no heat output?

 

[Dan]

Return line

The energy needs a way to return



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[passedpawn]

Ohms law doesn't lie. If there is voltage, and finite resistance, and a conductive path, current will flow. Check your wiring.

You say you have 120V going to each leg. I am going to assume you have 240VAC into your box. Are you sure you've got opposite phases to the connections to the element? 240VAC is split phase, in that you've got two hot wires 180 degrees out of phase. You need one of each on that element.

Measure the voltage between the leads of the element and make sure you've got 240VAC.

Now, if you are only getting 120VAC to your box, make sure one side of the element is hot (black wire), and the other is neutral (white wire).

 

[Dan]

AC electricity confuses me to no end. DC is easy. Power, return.
AC with the 180 loops. Man its enough to drive me nuts


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[sandyeggoxj]

I'm with ya Dan! I am trying to figure this stuff out myself. I have learned quite a bit but far from knowing much. I like these problems though because it helps me learn.

 

[Dan]

I'm with ya Dan! I am trying to figure this stuff out myself. I have learned quite a bit but far from knowing much. I like these problems though because it helps me learn.

That's a wonderful perspective.


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[sandyeggoxj]

That's a wonderful perspective.


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Without problems you wouldn't know what you don't know.

Anyways, sorry for the hijack. PP had some good questions. Do you have both hot legs going to the element? I would assume that is yes because it stopped working. What were you testing to get the 120vac for each leg? Were you measuring the potential to ground? Do you have any gfci or anything? What controls your SSRs?

 

[KEG99]

I finally got the element to work. Although I had it direct wired, I did have one leg still going through a selector switch (that I thought was good). . When measuring across each leg separately, I would get 120v. But when I finally checked across both legs I did not get 240v.

So I bypassed the switch and wired DIRECTLY BOTH legs to the element and it WORKS! It looks like the selector switch had gone bad. Still don't know why even when going through the bad switch I got 120v on each leg. That's what threw me off.

End result, I'm going to go through and replaced my SSR, my selector switch and clean up some wiring. Got to get this back and running. Got some brewing to do.

Thanks for your troubleshooting advice. I usually don't post since I like to figure this out on my own, but this time it really messed me up. Thought I had all options covered and . . . oh well.

Sorry to waste your time.

 

[Bobby_M]

What selector switch were you using to switch 240v/30amps? There are not many out there that can handle that kind of current so that would explain why you had a failure.

 

[Dan]

Pappy said Ohms Law a little earlier in this thread.

I will totally admit I used to know and use all the variations of Ohm's law but have forgotten most of them now.

Electricity and hydraulics are the most awesome things ever, in my opinion.

F... Ive forgotten to much. Lazy brain, lazy man.


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[Brumateur]

Still don't know why even when going through the bad switch I got 120v on each leg. That's what threw me off.

When you measured voltage on a leg connected through bad switch - you actually measured voltage from another leg wich was passed through heating element.
When you troubleshooting element you need to measure voltage on it directly

End result, I'm going to go through and replaced my SSR, my selector switch and clean up some wiring. Got to get this back and running. Got some brewing to do.

Most likely your SSR is OK. But as was mentioned by Bobby_M your switch probably is not rated fro 25A. Double check it otherwise you will burn switch again.

 

[KEG99]

The switch is a simple toggle switch rated at 20 amps. It switches between the element on the HLT and the one on the BK. I don't use it to switch from one element to the other under load. But . . . I may have done so by mistake.

I use a separate toggle switch on the PID output to the SSR to switch off an element if I need to for some reason. Sometimes, though, I have turned on the element after mashing, thinking I was heating up the BK, only then noticing it was still switched to the HLT. So I quickly toggle it to the BK and . . . well a 20 amp switch just doesn't like switching a 25 amp element.

 

[passedpawn]

The switch is a simple toggle switch rated at 20 amps. It switches between the element on the HLT and the one on the BK. I don't use it to switch from one element to the other under load. But . . . I may have done so by mistake.

I use a separate toggle switch on the PID output to the SSR to switch off an element if I need to for some reason. Sometimes, though, I have turned on the element after mashing, thinking I was heating up the BK, only then noticing it was still switched to the HLT. So I quickly toggle it to the BK and . . . well a 20 amp switch just doesn't like switching a 25 amp element.

My old control box switched the output from one PID to two SSRs. Worked great for 5 years.

If you want to switch the full current (23A) to two different loads, here is a DPDT switch that will work for you.

http://www.ebay.com/itm/3025I-Bryan...826?pt=LH_DefaultDomain_0&hash=item232dc6e4fa

 

[KEG99]

Good idea on the heavy duty switch. But I like doing just as you said, switching the PID output on or off.

The take away for others (and for me) trying to diagnose electric problems: Always disconnect your wires.

If you don't you could be reading backfeed from other components, like me reading 120 v backfed through the element.

 

[wstev]

What brum said...
If your troubleshooting any A/C circuit to ground or neutral then you'll troubleshoot all day and drive yourself nuts and most likely never find your problem. You HAVE to measure line to line or (line on line) to find an open especially on anything above 120v. Best way is to start with one lead on line 1 at incoming power, and follow the wire with your second lead, you should find 0 volts all the way to your element (if it's turned on and heating). If you find 120v(or 220v in a 220v circuit such as an element) after any component or wire then you found your problem.
When you troubleshoot line to line, your looking for 220v(apx) and as soon as you find 120v on one side and 220v on the other side of your component, then that's your open(bad) wire or component. I'm not going to get into 3 phase troubleshooting today, that's for another rainy day.
You can only troubleshoot to ground when troubleshooting DC. I deal with those kinds of problems on daily basis.


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[brewery_fixer]

You are simply wrong, you absolutely can troubleshoot AC circuits to ground


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