York Chiller Teardown

[bunglebear]

We've been pulling an old York Centrif down this week, and pulled out the impeller. It must have been rebalanced, because the one side of it has been ground (on the shroud) the lip where it sits on the eye seal is ground down quite low. I have not seen it done like this, so was wondering if this is normal practice to rebalance an impeller. Surely it can't be the correct way as it must have had 4-5mm taken off it in a band about 100-120mm wide all the way from the eye inlet to the outlet into the diffuser ??

[klove]

Sorry to tell you this, but that's the way they do it. Some are worse than others, some don't need it at all. If you look on the back side, there's probably a raised ring that's used to balance by grinding on it. I've seen gaps in those rings almost flat with the backside of the impeller. If the runouts are good, you may want to have the balance checked for your own peace of mind, but it's probably O.K.

[bunglebear]

We used to send them to Boeing near the International Airport and they used to do them for us. I was surprised to see this one because it doesn't look so good. On Monday, I will check runouts etc and go from there. Don't remember seeing a ring on the back, but forgotten as this all happened on Wednesday.

[turbomaster]

Not York, but grind marks for balance.... yes they do get pretty aggressive sometimes. Obvious shiny marks at the 3-6 O-clock position

[the007]

heh heh heh....you been grinding on there, eh, mikey.....but really, every york i've yanked apart has had impellers that were ground on, whether front or back. in fact, got one sittin' on the ground now ground on both sides.

[turbomaster]

heh heh heh....you been grinding on there, eh, mikey.....but really, every york i've yanked apart has had impellers that were ground on, whether front or back. in fact, got one sittin' on the ground now ground on both sides.

Me.. grind an impeller.. never intentionally! You're right though I don't think I can recall an impeller that hasn't had some balancing done on it, it's the nature of the beast. Doesn't look right though until you've seen it a few times. Here's this nice pretty impeller with these big gory gouge marks in it that appear to have no pattern, kinda freaks a fella out!
Hey I have a real small mechanical room ( with no vent fans) that I need to do a rebuild in and I've been eating a lot of pinto beans... wannna help? LOL

[turbomaster]

Here are some pics of a high speed wheel, front and back with the aforementioned grind marks, enjoy. Sorry it's not too clean :(

[the007]

i swear the starter cabinet at sears northgate still stinks to this day!!!!!