imi mastair cellar cooler

[mcunliffe4]

could anyone please explain why evap fan slows down when refrigerating and speeds up when off cylcle, no fn speed control fitted, whats happpening is the evap gradually ices up oovvr a period of time due lack of aiir flow through coil, many thanks guys

[Grizzly]

Just a complete guess, but could the actual temperature of the fans.
Be affecting how fast they rotate?
Could there be moisture within the fan bearings?
Grizzly
Grizzly

[mcunliffe4]

thanks for the reply grizzly, but whats happening is that the speed of the fan speeds up and slows down everytime the the stat is adjusted, think its loosing voltage across the stat, contacts could be worn gonna pop back 2moro with a new stat and try that

[mad fridgie]

On the theory side, as the air becomes colder it becomes more dense (heavier) the fan has to do more work, thus slows down, I do not think this is your problem, sounds like a ****y motor to me!

[multisync]

It must be a bad connection as I believe the fan is a two speed but one of the speeds will be in a terminal block as 'spare'

[Grizzly]

Nah Mate!
I have done some digging.
Please view the attached word doc. Showing the dip switch settings that could well be behind the cover of your "Standard Controller"
These refer to fan control being temp related. See what you think?
Sorry about the size only It's
the only way I could reduce it small enough!
Grizzly

[multisync]

Nah Mate!
I have done some digging.
Please view the attached word doc. Showing the dip switch settings that could well be behind the cover of your "Standard Controller"
These refer to fan control being temp related. See what you think?
Sorry about the size only It's
the only way I could reduce it small enough!
Grizzly

I guess I'm showing my age as I was thinking about the old style..but looking at the diagram it can't be a bad connection even if it was the old style...

[Andy W]

I vaguely remember having a similar problem on a marstair and it was a bad neutral on the fan capacitor.

[mcunliffe4]

thanks for the replies guys, Grizzley theres no pcb on this plant, simple mechanical stat, what i found is that the fan on evap, lc170 i think is a 2 speed motor like multisync said, other company had been there hhad wired it incorrect on the stat, changed crimps on stat and away it went at a faster speed, keeping a coonstant speed while refrigerating annd durinng off cycle,many thhanks to everyone for there helpful hints....

[Grizzly]

thanks for the replies guys, Grizzley theres no pcb on this plant, simple mechanical stat, what i found is that the fan on evap, lc170 i think is a 2 speed motor like multisync said, other company had been there hhad wired it incorrect on the stat, changed crimps on stat and away it went at a faster speed, keeping a coonstant speed while refrigerating annd durinng off cycle,many thhanks to everyone for there helpful hints....

Thanks for updating us all.
Nice One!
Grizzly