Extractor fans ?

[the_constructor]

How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

[Allan Mac]

cheap and cheerful, go noisey after a couple of years useually driving customer nuts before complete failure. (depends on useage of course). Allan

[Peter Scott]

I've replaced a ceiling fan with a new one pumping 85 cubic metres per hour. I am a bit disappointed with the performance. The calculations suggest it should clear the whole room in six minutes. However it doesn't keep pace with the steam during a shower. It feeds a one metre pipe into a chimney. Am I being too optimistic? The room clears fairly quickly after the shower goes off. But SWMBO thinks the room should stay clear. Perhaps I need to go up to an inline one with higher throughput? I do keep the door slightly open and I don't think the chimney is blocked.

Peter Scott

[js.b1]

You get what you pay for - except where idiot marketing take the piss.

Cheap fans Cheap bearings which get noisy, hopefully before they seize which is when nasty things happen.

Xpelair. Quality bearings with a long life, typically electronic control or shutters breaks first. The GX range and others are UK packaging around contract manufactured German EBM-Papst motor & bearing. You can usually find EBM or EBM-Papst embossed on the motor casting.

Vent Axia. Can not recall, often more expensive, typically more commercial in focus (better shutters).

The problem with AC fans is when the bearings seize. A fan by its nature suffers lint adhesion to fan impellor and particularly motor body. Lint is highly insulatory and highly flammable. When bearings seize on a DC fan the electronics detect the stalled condition and turn current on & off - so limiting motor heating. When bearing seize on an AC fan there are no electronics just a bimetallic strip that opens & closes based on the temperature of the motor. In some cases this bimetallic strip is not present, arcs badly with a stalled inductive load or operates at too high a temperature with the result that the assembly overheats - no fan means no airflow. Overheating can be sufficient, given long enough, to result in lint igniting - particularly if combined with oil leakage from worn bearings or grease from kitchen extractor usage.

In industrial settings AC fans are typically metal housing, metal impellor, metal struts, metal motor enclosure to act as a heatsink and a bimetallic strip thermal cutout. Loss of cooling is usually noticed by widgets no longer moving or secondary overheat alarms.

In domestic settings a lot of cheap fans use low temperature thermoplastic motor-struts, impellors, housings and may not include a bimetallic cutout (or at least one functioning correctly). Some are more prone to lint buildup due to impellor design and low grade bearings will deposit a continual stream of ejected lubricant due to inadequate seals & dust ingress wear.

This problem applies to extractor fans, cooker hoods (grease buildup), tumble dryers (fine lint builds up past the filter ready to flambe) and dehumidifiers (which use cheap motors & bearings).

Always check Ebay, you can sometimes pick up boxed new Vent Axia & Xpelair at good prices. The bad news is that they continually change - eg, parts for 1995-97, 98-01, 02-05, 06-present. So you may a) not be able to get parts if too old b) need to check carefully exactly what parts are required.

It is sad that DC fans have not replaced AC totally now - although that will introduce low quality DC power supply failures (cue being sold separately at inflated parts prices).

[John]

Do you have satisfactory arrangements to allow 85 cubic metres of fresh sry air into the room - without resistance?

[John]

...fresh Dry air.....

Many people miss this important aspect - it is so important.(otherwise you are trying in vain to create a vacuum)

[ARWadsworth]

I think that you are a little too optimistic. I recently fitted an inline fan that extracts 220 cubic metres per hour for a customer. I can assure you that the shower still steams up the room when in use. I left the fan with a 10 minute timer overrun, however the room is clear after 2 minutes.

Adam

[Peter Scott]

Thanks. That's reassuring, and will get me out of trying another one. I've got expert opinions to back me up now!

Yes, I have avoided lack of air by opening the door a small amount. The house is well sealed but has open but unused chimneys so I think the air flow will not be impeded.

Peter Scott

[John]

Drawing air down a chimney is not an "easy" route for the air.

Would a dedicated air vent in the bathroom be possible?

[Andrew Gabriel]

The Manroses originally installed in this house all seized (silently) and burned out their motor windings (no resettable thermal trip - not designed to be repairable).

Replaced with Deta. Had one seize, but it has a resetable trip, so I repaired it, and it's worked fine ever since. Sadly, they don't seem to be in business anymore. Mine have thermal solenoid operated shutters.

Also have a Vent Axia which I picked up for peanuts but should have been very expensive, and it's run for years with no issues. Has magnetic solenoid operated shutters too.

I was given a second-hand Xpelair which is 30 years old. Ran continuously for 10 years before I got it, and I've used it during the summers since. This year, it started seizing, being slow to start up. I cleaned and oiled the bearings and it worked for several more months, but is starting to do it again now.

[Doctor Drivel]

Would synthetic high melting point grease be better on the fan bearings? Although buying this sort of grease is not cheap.

[Doctor Drivel]

Manrose are cheap, noisy tat. Buy Xpelair or Ventaxia.

[Andrew Gabriel]

Bearings don't get hot, and I suspect they need a low friction oil. They're lubricated by a tiny amount of oil in the phosphor bronze (or on some, just by a high lead content phosphor bronze alloy). I think the problem is caused by dust eventially getting into the bearing. Cleaning this out helps, but it has scored the shaft. Only oil I have to hand is (clean) engine oil, and I suspect that's much to viscous to be absorbed into the bearing surface.

[PeterC]

Last time I replaced a plain bearing it needed oil as it was dry. Doing it at work enabled the use of vac. pump - amazing amount of air came out - then let atmospheric pressure push the oil in. This method might not be possible at home, but heating the oil with the bearing in it (poss. 70 - 80C should be OK and not damage anything) then letting it cool would get a lot more oil in to the bearing. Assuming that the bearing can be removed - not a good method if not.

[pcb1962]

I recently replaced the extractor in our downstairs toilet with one of these:

builders had installed a normal bathroom fan, with almost 3m of flexi ducting, including 2 90 degree bends, so the net effect was absolutely no extraction at all. The new one howls a bit, you certainly know it's working, but it clears the room of bad smells in a few seconds. Going to use the slightly more powerful version ( ) in the upstairs bathroom which has similarly found itself in the middle of the house with a long run of ducting when we put an extension on the side of the house.

[ARWadsworth]

Swapping the flexi ducting with proper pipe also helps.

Adam

[pcb1962]

Yes I did that, I think that's the cause of the 'howl', I'm sure the flexible ducting would be quieter, though more restrictive.

[Peter Scott]

No. It's right in the middle of the house with no external wall or window. Walled in by an extension. Thanks for the suggestion

Peter Scott

[Peter Scott]

It was my first experience of ducting, so I'm finding out as I go. It seems to be a good idea to keep it fairly stretched or it might collapse. Perhaps this has happened with yours?

Peter Scott

[Peter Scott]

Seems like it's a good idea to pay a bit then?

Peter Scott