SSR relay problem solution

mdkmdk · Jun 17, 2022

Hello everyone,

I have a goldsmith oven to which I had to change an SSR relay because when it reached 475 degrees centigrade the temperature increase stopped. Since the oven must reach 800 degrees in about two hours, I have to solve the problem.

I changed all the main components to the oven: thermoregulator, thermocouple, resistance. The problem of increasing the temperature was present even before changing all these components.

I ordered an SSR relay of the same brand and model as the one mounted on the oven: Crydom D2425.

Since it was panel mounted I proceeded to modify the panel to put a heatsink in it.

Between the heatsink and the relay I put some Thermalright TFX thermal paste which has a high thermal conductivity power and is also used in computers and can withstand up to 300 degrees.

After having reassembled everything I turned on the oven, this time it reached 100 degrees centigrade after 10-15 minutes the increase in temperature stopped.

I wonder where he went wrong about the SSR relay changing as I think I've done everything possible. Could anyone help me? Thank you in advance for your reply.

I attach some photos to the message.

James · Jun 17, 2022

check you are getting a voltage across a1 and a2 on the ssr
without that control voltage the relay turns off.

mdkmdk · Jun 18, 2022

James said:
check you are getting a voltage across a1 and a2 on the ssr
without that control voltage the relay turns off.

how can i do to verify that?

DPG · Jun 18, 2022

mdkmdk said:
how can i do to verify that?

Multimeter set to appropriate range.

mdkmdk · Jun 18, 2022

DPG said:
Multimeter set to appropriate range.

I'm not expert with the multimeter, could you explain me how to set the multimeter to the appropriate range? Thanks.

DPG · Jun 18, 2022

mdkmdk said:
I'm not expert with the multimeter, could you explain me how to set the multimeter to the appropriate range? Thanks.

Are you using an auto ranging meter?

mdkmdk · Jun 18, 2022

DPG said:
Are you using an auto ranging meter?

Yes, it's not manual.

DPG · Jun 18, 2022

mdkmdk said:
Yes, it's not manual.

The SSR is DC controlled. Set your meter to DC Volts

plugsandsparks · Jun 19, 2022

As above, set your multimeter to DC volts range so you can pick up 3-32 volts. Connect Positive lead to 3 and common or negative lead to 4. MAKE sure you are reading volts not current....
If you get a reading between 3-32V the heater should be on and stay on until the reading drops below 3V

hope this helps

P&S

mdkmdk · Jun 23, 2022

plugsandsparks said:
As above, set your multimeter to DC volts range so you can pick up 3-32 volts. Connect Positive lead to 3 and common or negative lead to 4. MAKE sure you are reading volts not current....
If you get a reading between 3-32V the heater should be on and stay on until the reading drops below 3V

hope this helps

P&S

Does the oven have to be switched on during measurement or switched off?

telectrix · Jun 24, 2022

duplicate thread here along with the transformer query.

DPG · Jun 24, 2022

mdkmdk said:
Does the oven have to be switched on during measurement or switched off?

It needs to be on - you are measuring voltage.

I think you may be out of your depth with this one. Take care when making any tests etc.

mdkmdk · Jun 24, 2022

DPG said:
It needs to be on - you are measuring voltage.

I think you may be out of your depth with this one. Take care when making any tests etc.

Yes, the transformer is from the same oven as this thread (sorry if I inadvertently created a duplicate of this thread, if you see fit please delete the other thread and leave this one). Why do you think the approach of changing everything is not good? The only things left to change are the rectifier bridge and the transformer, I don't know what to do to solve the problem that seems to have a completely unknown cause.

DPG · Jun 24, 2022

mdkmdk said:
Yes, the transformer is from the same oven as this thread (sorry if I inadvertently created a duplicate of this thread, if you see fit please delete the other thread and leave this one). Why do you think the approach of changing everything is not good? The only things left to change are the rectifier bridge and the transformer, I don't know what to do to solve the problem that seems to have a completely unknown cause.

Well I suppose it depends how much time and money you are willing to spend on it. What happens if one faulty component is damaging another? If that's the case and you keep replacing single items you will never fix it.

mdkmdk · Jun 28, 2022

plugsandsparks said:
As above, set your multimeter to DC volts range so you can pick up 3-32 volts. Connect Positive lead to 3 and common or negative lead to 4. MAKE sure you are reading volts not current....
If you get a reading between 3-32V the heater should be on and stay on until the reading drops below 3V

hope this helps

P&S

I made the measurement you suggested, the value is 22.4 v at start-up and 23.0 v when the temperature stops and no longer increases, I am attaching the photos of the multimeter set on two different ranges

DPG · Jun 28, 2022

mdkmdk said:
I made the measurement you suggested, the value is 22.4 v at start-up and 23.0 v when the temperature stops and no longer increases, I am attaching the photos of the multimeter set on two different ranges

If that's a measurement at the SSR input then that is enough to switch it on. The 0.6V difference won't have any effect.

mdkmdk · Jun 28, 2022

DPG said:
If that's a measurement at the SSR input then that is enough to switch it on.

Yes, the measurement is at the SSR input. This time at 88 degrees Celsius it has stopped rising further, when you turn it on you can hear the hum of the resistance, when the temperature stops rising you no longer hear any hum. (The resistance has been changed and tested)

DPG · Jun 28, 2022

mdkmdk said:
Yes, the measurement is at the SSR input. This time at 88 degrees Celsius it has stopped rising further, when you turn it on you can hear the hum of the resistance, when the temperature stops rising you no longer hear any hum. (The resistance has been changed and tested)

Well, at the voltages you are measuring there the SSR should be switched on, assuming it isn't faulty of course.

mdkmdk · Jun 28, 2022

DPG said:
Well, at the voltages you are measuring there the SSR should be switched on, assuming it isn't faulty of course.

With the old SSR relay the temperature stopped rising to 475 degrees centigrade and didn't rise anymore, but now it seems to stop rising at ever-changing temperatures.

DPG · Jun 28, 2022

mdkmdk said:
With the old SSR relay the temperature stopped rising to 475 degrees centigrade and didn't rise anymore, but now it seems to stop rising at ever-changing temperatures.

So is the SSR switching as it should now? That is, is it on when it has a voltage between 3 and 30VDC at its input?

mdkmdk · Jun 28, 2022

DPG said:
So is the SSR switching as it should now? That is, is it on when it has a voltage between 3 and 30VDC at its input?

The oven should reach 800 degrees centigrade in about two hours, when I took the measurement with the multimeter the oven was on.

DPG · Jun 28, 2022

mdkmdk said:
The oven should reach 800 degrees centigrade in about two hours, when I took the measurement with the multimeter the oven was on.

So the SSR is working correctly then?

The fault must be elsewhere. Have you got a wiring diagram for this oven?

mdkmdk · Jun 28, 2022

DPG said:
So the SSR is working correctly then?

The fault must be elsewhere. Have you got a wiring diagram for this oven?

I don't know, from the input measurements with the multimeter it would seem so, unless it was sent to me faulty.

DPG · Jun 28, 2022

mdkmdk said:
I don't know, from the input measurements with the multimeter it would seem so, unless it was sent to me faulty.

You can't tell from the input measurements alone - you need to make sure it operates (ie switches on) when the input voltage is present.

mdkmdk · Jun 28, 2022

DPG said:
You can't tell from the input measurements alone - you need to make sure it operates (ie switches on) when the input voltage is present.

How can I do to understand if it switches on?

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