Yaxun 850 (220v) – New blower shows lower resistance than original - Page 1
Forum section: electronics / general

author: GreatField
author_rank: Newbie
timestamp: September 27, 2025, 04:01:09 pm
content: I bought a new blower (220V) because the inner glass tube in the old one was broken. Then I decided to measure the new heater resistance and the value was 29.6 Ω. After that, I measured the old heater and the value was 82.3 Ω. That made me suspicious, so I did some research and found:Resistance ≈ 33 Ω → blower for 127VResistance ≈ 90 Ω → blower for 220V[ Attachment Invalid Or Does Not Exist ]What do you think? Did the seller make a mistake and send me a 127V blower, or is it normal for a brand new 220V heater to have a lower resistance value?

author: tom66
author_rank: Super Contributor
timestamp: September 27, 2025, 04:22:35 pm
content: At 29 ohms, the cold power of the heating element will be around 1700W. As it warms up it will reduce - probably to around 1/2 to 2/3rds of that power. If that power level matches your expectations, then it's probably OK. If it's supposed to be much lower power it may go bang as soon as, or almost as soon as the power is connected. For what it's worth, I'd expect a hot air gun to have around a maximum 500W heating element, so it does seem wrong to me.

author: GreatField
author_rank: Newbie
timestamp: September 27, 2025, 04:46:43 pm
content: Make sense, on the yaxun 850 label tell270W.I avoided turning on for this and other reasons.

author: floobydust
author_rank: Super Contributor
timestamp: September 27, 2025, 05:03:04 pm
content: My 858 heater story. The tube ground connection is important too.

author: GreatField
author_rank: Newbie
timestamp: September 27, 2025, 06:32:21 pm
content: You made a good measurement, but your station has an intermediate circuit, while mine doesn't. There are only two wires that connect directly to the two poles of the resistor inside the blower.I decided to open it up to remeasure the resistance, and to my surprise, the resistance value of the new blower, which was 29.6 ohms,now shows 51.4 ohms.Yesterday I measured it three times, and the resistance was exactly 29.6 ohms on both occasions. I also measured the resistance of the old blower, measuring 82.3 ohms.You can see that only the resistance of the new blower changed from yesterday to today, since the resistance of the old blower is practically the same. I'll open up the new blower and measure directly to the resistor to confirm the value and rule out any problems with these wires.See the image below:

author: GreatField
author_rank: Newbie
timestamp: September 27, 2025, 06:54:15 pm
content: Now I understand what happens. As I touch the new resistor or move it, the new resistor changes its value and assumes different values, sometimes exceeding 100 ohms.I took the old resistor and moved it, but its ohmic value remains constant at 83 ohms. Is this characteristic of a new resistor, or is it a defect?

author: GreatField
author_rank: Newbie
timestamp: September 27, 2025, 10:01:03 pm
content: The variation in the measurements was due to the wire or connector not being 100% secure, since when removing the resistor and measuring it directly, no variations were observed.Anyway, the conclusion is that this resistor is certainly not a 220V one, so I'll return it.