Thermal relay, how to solve the problem of chatter (noise in the network)?

Question

Do it yourself

To control the temperature in a self-made 'computer' case (placed on a covered but not warm balcony) through the control of a duct fan (220v, it seems ~ 30w / h), a thermal relay was purchased in the first available store with electronics, there was a marking on the case (but google pro she said that this is a type of either a case, or a handle over a tuning resistor, if it’s critical, I’ll pull it out of a rather deep place in the case and look again), so I’ll consider it someone’s handiwork.
The relay is purely mechanical (a quiet click is heard when switching), operates in the range of -30 .. + 30 (I was offered exactly the same in appearance but in the range of 0 ... + 60) and has three outputs, allowing you to control the device as a decrease in temperature as well as for promotion.
Switching to a temperature change of 2 degrees was announced (orally by the seller, to the question about chatter).
The device works properly, even the temperature marking on the threshold value adjustment knob matches the reality, but there is a very serious problem. Until the moment of shutdown, in about 1-2 seconds, computer speakers give out a quiet noise of sparkling contacts, but the relay itself does not rattle.
Everything would be fine, but over the past few days, one old computer began to hang stupidly on me, and it was at the moment of switching the thermal relay (I noticed it twice).
Attention, the question is whether this problem can be solved by some free method (I think I can buy a soldered part somewhere outside, there is a case) or what device to buy that will not have such a problem.
I vaguely guess that digital thermal relays will not have exactly such a problem, but here the famous toad comes in, which strangles, i.e. the question is how much cheaper. I bought this relay for ~ 450r, I think it's a bit expensive for the details that it contains, judging by the diagrams on the Internet.

Answer 1

It's hard to give advice without seeing the diagram.
Try soldering on the relay contacts (which rattle) a capacitor suitable for voltage somewhere around 2 times.
The second option is to abandon the mechanical relay and install a solidstate or make a key yourself on a triac with an optocoupler.

Answer 2

- goo.gl/22I03Q
sorry for the chicanery, there are many options for solving the subject
- perhaps the electric motor itself is "noisy"
- the simplest and most obvious solution is to plug the problem device (a computer that hangs) into another outlet, i.e. Do not power from a common extension cord.