Guys who have built PID controllers
- Thread starter razor1115
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orangehero
Well-Known Member
Reread Bobby's post again carefully. He doesn't mean not having the DC control signals connected. SSR's leak a tiny amount of current so you will always see some voltage across it.
if the elements are on and no signal is hooked to the ssr telling it too, you have something wired wrong
This is how it's supposed to be. In order for power to be delivered to the element current must be flowing. The SSR cuts off the flow of current when off, but you still have voltage on the element. That's why you need a 2 pole switch/contactor to disconnect voltage from the element for safety.
Electric current is analogous to water flowing thru a hose, and the SSR is like a valve. Voltage is like the water pressure in the hose. Think about a hose connected to fitting with a restrictor plate (the element) with another hose connected to the downstream side of the restrictor plate, and a valve on the downstream hose. Now put a pressure meter (volt meter) on either side of the restrictor plate. With the valve closed (SSR off) you measure the same pressure (voltage) on either side of the restrictor plate (element.) If you open the valve (SSR on), water (current) flows, and the pressure (voltage) remains the same on the upstream side of the restrictor plate (element), but goes to almost zero on the downstream side.
Brew on
Completely understand all this (I am an engineer). What I don't understand is why the element is heating while the SSR 12VDC control wires are completely disconnected and the SSR lamp is also off (which it should be with wires completely disconnected from the PID).
When I unhook one leg of the 240VAC circuit, either the one from the main power control relay that runs to one leg on each boil and HLT control relay, or I unhook the other leg that is controlled by the SSRs, the element stops firing (as expected just like it would if the SSR were turning off the leg of the circuit it controls). With them both wired according to the diagram, the element fires as soon as I energize the relay coil for each respective element. That's what has me stumped...
When I unhook one leg of the 240VAC circuit, either the one from the main power control relay that runs to one leg on each boil and HLT control relay, or I unhook the other leg that is controlled by the SSRs, the element stops firing (as expected just like it would if the SSR were turning off the leg of the circuit it controls). With them both wired according to the diagram, the element fires as soon as I energize the relay coil for each respective element. That's what has me stumped...
This is how it's supposed to be. In order for power to be delivered to the element current must be flowing. The SSR cuts off the flow of current when off, but you still have voltage on the element. That's why you need a 2 pole switch/contactor to disconnect voltage from the element for safety.
Electric current is analogous to water flowing thru a hose, and the SSR is like a valve. Voltage is like the water pressure in the hose. Think about a hose connected to fitting with a restrictor plate (the element) with another hose connected to the downstream side of the restrictor plate, and a valve on the downstream hose. Now put a pressure meter (volt meter) on either side of the restrictor plate. With the valve closed (SSR off) you measure the same pressure (voltage) on either side of the restrictor plate (element.) If you open the valve (SSR on), water (current) flows, and the pressure (voltage) remains the same on the upstream side of the restrictor plate (element), but goes to almost zero on the downstream side.
Brew on
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I swear I posted in this thread. Was it the move? Am I banned? 
Bad luck with two bad ssr's. I guess try a third. Maybe from a different source. Don't use those "made in China" ones they have a 66% failure rate
Bad luck with two bad ssr's. I guess try a third. Maybe from a different source. Don't use those "made in China" ones they have a 66% failure rate
There are two versions of this thread. Weird. Reported.
I swear I posted in this thread. Was it the move? Am I banned?
Good info - I felt the same way! I ordered 2 SSRs and had this issue, troubleshot it, determined SSrs are the culprit. Ordered 2 more SSRs, although they WERE Fotek from a different supplier and still the same results.
I thought, no way 4 bad SSRs?? But the wiring is very simple and easy to follow, so I guess it's time to find some Auberins? Anyone recommend any other U.S. brands?
Try Mager SSR's from ebay. Auber just rebrands these, and the part numbers are the same. I haven't seen any reports of issues with Mager SSR's. Although if you are willing to pay a little more to get customer support, go with Auber.
Brew on
Dfitz
Well-Known Member
I recall your thread on the other site. Haven't been on there since though. Did you rule out whether an ample amount of conductive paste was the culprit?
Yessir - even with the DC leads disconnected, as soon as relay is close, SSR fires.
Who woulda thought... went through 4 Fotek 40A SSRs and all were bad from the start... ordered these, Mager SSR 40A (thanks Doug for the recommendation), and everything works like expected. Cheap China crap has a place, just not in powered electronics!
Who woulda thought... went through 4 Fotek 40A SSRs and all were bad from the start... ordered these, Mager SSR 40A (thanks Doug for the recommendation), and everything works like expected. Cheap China crap has a place, just not in powered electronics!
I feel your pain I did the same thing years ago
[duplicate threads merged]
kenglish427
Member
I am going thru the same issue getting them to work properly. One thing that helped me in troubleshooting(other than being a Licensed electrician) was installing a Amp meter onto my control panel, its pretty easy to see if you are somehow running on half the power(if your relay works, but is wired wrong and you operate on 120V) you will see about 12-13A or current draw, or if your operating at full heat (240V @ 26-27A) then you know you have a failed relay. Also, if you start tripping breakers at your house, you can visibly see why, and possibly shed load. I think it was about $10 on amazon, and has a pretty blue LCD screen
Weaselbrewery
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cheers for the great advice, really helps a newbie with melting ssr probs.
There is a $15 40amp ssr on ebay with heatsink and thermal grease, it looks the same as mager one (blue and clear plastic? you recon it is worth a try or any recommendations where to get a decent relay to power a blichmann boil coil 5000w i think.
Australia if poss or will order from usa, also can you use a voltage regulator to turn down the coil for a steady boil?
Thanks in advance.
There is a $15 40amp ssr on ebay with heatsink and thermal grease, it looks the same as mager one (blue and clear plastic? you recon it is worth a try or any recommendations where to get a decent relay to power a blichmann boil coil 5000w i think.
Australia if poss or will order from usa, also can you use a voltage regulator to turn down the coil for a steady boil?
Thanks in advance.
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