Inline extractor fan - lots of power, then drops?

hughtrimble · 4 Jun 2021 at 19:30

Evening forumites,

I have a Manrose MF100 25W inline mixed flow fan and I've noticed that sometimes when I first switch it on, it provides a burst of high speed fan and powerfully (in a very good way) sucks in the air, but then after a second or two, slows to a much lower speed and suction power which it retains until being switched off. The initial power burst does not happen every time it is switched on, only occasionally.

I've just checked its connection wires and all are secure and sturdy. I've also checked that the fan is set to its highest speed option.

Ideally, I'd like it to stay at that hefty power as then it would clear the steam out of the windowless bathroom nice and quickly.

Any pointers as to what could be causing that initial power burst then drop?

Hugh

NoobCannon · 4 Jun 2021 at 20:28

Looks like it can be wired for 2 speeds. So if you want the higher speed all the time you need to change the switched live terminal. As to your specific problem ive no real idea.

edit:- checked the manual and its a jumper on that model.

EH75 · 5 Jun 2021 at 08:17

I had a problem with a different manrose fan doing weird things like power dropping etc. I triple checked all the wiring etc but couldn't see any problems. Got in touch with them and they basically said it sounded faulty and replaced it under warranty. So it could be a problem with the fan itself.

hughtrimble · 5 Jun 2021 at 10:03

EH75 said:
I had a problem with a different manrose fan doing weird things like power dropping etc. I triple checked all the wiring etc but couldn't see any problems. Got in touch with them and they basically said it sounded faulty and replaced it under warranty. So it could be a problem with the fan itself.

Good call, I'll contact them directly about it.

hughtrimble · 5 Jun 2021 at 10:04

NoobCannon said:
Looks like it can be wired for 2 speeds. So if you want the higher speed all the time you need to change the switched live terminal. As to your specific problem ive no real idea.

edit:- checked the manual and its a jumper on that model.

Thank you for this - this is what I checked the other day, to ensure it was indeed set to its fastest speed with the jumper. And it is set to it, so sadly no answers there.

The power burst speed is so very much higher than its standard high!