SSR relay problem solution

[mdkmdk]

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.

 

[DPG]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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?

 

[DPG]

How can I do to understand if it switches on?

I think this is beyond your abilities. You've already changed lots of items, and modified the oven with a heatsink. If you don't know how to test if the SSR is working then it is going to be difficult to advise further.

To be honest, if you had the same fault (not reaching full temperature) before and after changing the SSR then I can't believe it is faulty. Unless of course something is overloading it, such as a short circuit somewhere. But this is the problem when you approach fault finding by just replacing individual items.

 

[James]

Any electrical engineer should have the fault found within an hour, probably less than half an hour.

 

[marconi]

Please would you tell me the make and model number of the oven so that I can look up its details? Or even better send me a picture of its specification plate.

 

[mdkmdk]

Please would you tell me the make and model number of the oven so that I can look up its details? Or even better send me a picture of its specification plate.

Unfortunately there is no plate in the oven showing the manufacturer and the model of the oven, however it should be an oven built in the 90s.

 

[marconi]

Unfortunately there is no plate in the oven showing the manufacturer and the model of the oven, however it should be an oven built in the 90s.

Sorry, but without this information I cannot help you.