Manrose inline extractor fan (with timer)

Help Support Talk Electrician Forum:

Scubabob

Member
Joined
May 18, 2022
Messages
5
Reaction score
0
I have an inline fan installed in a bathroom, linked to the lights. All works fine, turn the lights on & the fan triggers. Turn the lights off & the timer runs as it should.

Now the problem. If you turn the kitchen under cabinet lights on it triggers the bathroom fan. It doesn't bring the bathroom lights on though, just the fan. If you then turn the under cabinet lights off the fan stops instantly (no timer overrun).

Just can't get my head round this. The under cabinet lights are LED on a electronic driver unit. The fan is a Manrose MFT unit..

Any ideas why the fan is triggering????
 

SPECIAL LOCATION

Trailer Boy - Electrician.
Joined
Mar 28, 2008
Messages
13,633
Reaction score
317
Sounds like something could be wired wrong...?

First step is back to basics, and dead test all the wiring..
verify their are no cross connections etc..
 

Scubabob

Member
Joined
May 18, 2022
Messages
5
Reaction score
0
Nope, no crossed connections. Perm live, switched live and neutral all as normal. All works normal , inc timer overrun. Under cabinet lights triggers the fan but not the lights and doesn't trigger the overrun. Weird .
 

Richard-the-ninth

Moderator
Staff member
TEF Moderator
Joined
Dec 24, 2013
Messages
1,153
Reaction score
96
As the fan starts when the kitchen LEDs are switched on, and stops when the kitchen LEDs are switched off (But the bathroom light stays off) I would suggest you change the LED driver for a differant brand (Same output voltage, but can be higher current) It may be possible to "Add a surpressor" but which one and what value.
 

SPECIAL LOCATION

Trailer Boy - Electrician.
Joined
Mar 28, 2008
Messages
13,633
Reaction score
317
Nope, no crossed connections. Perm live, switched live and neutral all as normal. All works normal , inc timer overrun. Under cabinet lights triggers the fan but not the lights and doesn't trigger the overrun. Weird .

No idea what you mean by "all as normal"?
Have you actually done ALL of the dead tests as per BS7671?

e.g. comprehensive continuity and insulation resistance tests on all relevant circuits?
 

Scubabob

Member
Joined
May 18, 2022
Messages
5
Reaction score
0
Yes. All tests done. Never come across anything like it before. Even been on to Manrose Tech. They've never seen it before. They thought maybe a faulty timer board, being spiked. Interestingly, connected a new fan and still the same. Disconnected the switched live and switched the bathroom lights on, no fan operation. Turned the kitchen under cabinet lights on and bingo, the fan runs even with the switched live missing.

Next , going to look at the LED driver on the cabinet lights .
 

Sensai

Member
Joined
Aug 15, 2020
Messages
24
Reaction score
6
Hi, it sounds like the 'permanent' live to the fan is coming via your kitchen lights hence the overun is not coming on when you switch them off as the fan has no power then. Voltmeter on the fan and try the lights in the kitchen. Does it register voltage when they are on and off?
 

Scubabob

Member
Joined
May 18, 2022
Messages
5
Reaction score
0
Permanent live is there. The Bathroom lights work fine with the fan running with timer overrun even with the under cabinet lights off. Everything as normal. The problem comes when you turn on the cabinet lights. It triggers the bathroom fan. The permanent live and neutral are present, the switched live disconnected and the fan still triggers.
 

Sensai

Member
Joined
Aug 15, 2020
Messages
24
Reaction score
6
Check the permanent live Line cable for voltage. Have someone turn the kitchen lights on and off and see if it becomes present as you may find they are joined somewhere. I just worked on some bathroom downlights lights connected to a Manrose fan and when the lights were isolated I found the fans permanent live came from a socket in the loft then to the light switch before going back up to the fan. It's switched live was part of the light circuit so at the switch I had isolated the lighting but still had a live cable for the permanent live so had to find the source for that.
 

Mike P

Junior Member
Joined
Oct 21, 2008
Messages
54
Reaction score
1
Location
Southampton
I would check polarity. Use earth as your reference and make sure you have 230v on Phase conductor and switch conductor and zero volts on neutral conductor. I had a similar fault with a customer where someone had looped the switch phase conductor through the tungsten lamp and then on to the next lamp causing low voltage and half power on lamps
 

Scubabob

Member
Joined
May 18, 2022
Messages
5
Reaction score
0
Update. It would appear the LED driver on the under cabinet lights has a frequency that is triggering the fan.
 

Richard-the-ninth

Moderator
Staff member
TEF Moderator
Joined
Dec 24, 2013
Messages
1,153
Reaction score
96
It would appear the LED driver on the under cabinet lights has a frequency that is triggering the fan.

Commonly known as interference.

How did you figure that out, and how are you going to resolve it?

And thanks for letting us know. :)
 

runningpiglet

Junior Member
Joined
Dec 2, 2010
Messages
10
Reaction score
3
Update. It would appear the LED driver on the under cabinet lights has a frequency that is triggering the fan.
Try disconnecting the cupboard lights and replacing temporarily with load of similar wattage and see if problem persists?
 
Top