Fuji HVLP Compressor Failure - Help and Repair WIP

[deema]

I’ve had a 4 stage Fuji HVLP for a few years, I’m no paint sprayer, but I have enjoyed using it and like the system. Yesterday, however, a puff of smoke an angry change of note in the compressor was followed by the lights going out. Right in the middle of painting the compressor had gasped for the last time and tripped the main RCD!

Well, at circa £800 for a new compressor there was nothing to loose but to take a screwdriver to see if I could fix it. The Q4 box is fairly big considering what it contains! I was extremely surprised that it’s not a sophisticated sci-fi system inside but a simple 4 stage tangential bypass motor.

The sort of thing you find in vacuums! After some help from a friend we believe they use a Lamb Ametek 4 stage 5.7" High Suction Vacuum Motor. It certainly looks identical to the photos of the unit. Anyway, if it were a 3 stage unit, a replacement is easily available at the princely cost of about £90 delivered off eBay. However I couldn’t find a 4 stage motor at this stage. So, the only thing to do was to strip it down to find out what was wrong. After a lot of head scratching we finally got it virtually all apart. The culprit was a cheap nasty 6000Z2 bearing that had totally disintegrated. This is located at one end of the motor and you have to take the fan assembly apart to get at it. At the other end of the motor is a 608RS2 bearing. Both are puny bearings for an industrial machine, and the remaining intact bearing is not even a branded bearing. The total cost to replace both of the bearings is c£5 for proper SKF beatings.

The next phase after we get the bearings is to see if we can get the fan assembly back together.

Are there any experts in these fans who could pass on any tips for reassembly / knows where I can get as a back up (if reassembly doesn’t work) a 4 stage fan unit?

I will pop some photos up if anyone is interested in the inner workings of a HVLP compressor. I can’t believe there is much difference in how any of the brands work. Interesting (to me anyway) the Greco HVLP unit appears to use exactly the same compressor unit. I found that you can buy the pump as a spare for their units..... but at a silly price! (almost the same as buying a new Fuji compressor)

 

[MikeG.]

.........any tips for reassembly.....

Sure, that's easy. You just look at the photos you took of each stage of the disassembly, and do everything in the reverse order. Simples!

 

[MikeJhn]

There are some e-bay links in this post: hvlp-investigation-and-review-t97520.html I don't think I found a four stage unit, but did consider two three stage to make a six stage unit.

EDIT: looks like all the links in the above post are now defunct, sorry for that, but it may be an interesting read.

This also may be of interest, Fuji bare four stage unit: https://www.axminster.co.uk/fuji-mini-m ... nit-951680

 

[deema]

:lol: :lol: :lol:
Thanks a Mike, your wisdom and insights on re-assembly are invaluable.

Appreciate your link to your earlier thread, I found it most helpful. Looking at the motors, what I can’t figure out is that Fuji are quoting PSI for the various turbines of 6 to 9.5 from the 2 to 5 stage. The 3 stage replacement unit I’ve found has a suction of 3500mm H2O at 0 CFM which is only 5PSI.....I know I must not be understanding things properly since it would appear that at zero flow the 3 stage units not as good as a 2 stage unit.

 

[MikeJhn]

I know when I was investigating this I did confuse myself on many occasions until I remembered we are on the other side of the turbine and not using it for it's intended purpose, we are looking for CFM output not suction, the PSI is to a larger extent irrelevant, it's just another measurement of air flow, not forgetting if we increase flow we decrease pressure, but you can't have one without the other, it was some time ago I did the initial investigation so can't remember it all, but I hope that helps.

 

[deema]

Thanks Mike, appreciated.

 

[Dibs-h]

Moddocks - http://www.europart.co.uk/s.nl/sc.2/category.2871977/.f

Maybe give these guys a call if all else fails? They are shown on Ametek's website as a UK distributor or something.

A quick Google coughs this up

https://www.pb-vac.co.uk/spares2.php?spareid=19

There is a 4 stage on there.

According to https://www.kleen-ritecorp.com/p-35256- ... -120v.aspx the model nbr you want might be 119292 but a 240v one maybe. Unless the Fuji takes 240v and steps it down internally to 120v.

Worth a call to Maddocks I think - if they don't have one - they could probably tell you what a replacement might be.

HIH

Dibs

p.s. Bit late but I 2nd MikeG's statement about photos whilst dismantling. I learnt to do that years ago - after learning the hard way. LOL

 

[deema]

Thanks Dibs
The main issue with dismantling the multi stages is that you can’t photograph it as it’s sealed up. As soon as you open it you have a few parts that have moved and I’m not certain of the exact order to put them back in!

 

[Dibs-h]

Post up some pics of what you "parts" you want to know the order in which they go in?

I have a Q4 sat around somewhere and I have a snake inspection camera and the tangential output does look way bigger than the 10mm the camera needs to poke thru.

 

[johnnyb]

I've found graco seem better quality bits( pipe, gun) fuji despite there large ticket price are a bit. ...poo.
ametek lamb are universally used in carpet cleaning machines. give them suppliers a go.

 

[MikeJhn]

On another thread you said Fuji are nice, but you prefer Graco, now you say Fuji are poo, make up your mind.

What Fuji outfit do you have that you are comparing to the Graco?

 

[deema]

Interesting views, my research has confirmed that the Fuji and Greco systems use exactly the same compressor motors. Both use the same Ametek units.

4 stage unit is a 117 246 00
5 stage unit is a 122146-00

Ametek also seem to have a 6 stage unit.

Thanks Dibs for the offer, I forgot to take a photo today of the bits I’d like to know the exact sequence for assembly.

 

[deema]

Hi Dibs
These are the parts I need to rethread back onto the spindle of the motor. Any pics of the sequence would be appreciated

 

[Dibs-h]

Thanks for the pictures - I'll dig out my Q4 tomorrow and see what I or the inspection camera see.

In the meantime:

Yes - I'm intentionally mentioning them in order of 1, 3, 2.

1. Top cover looking at the unit from the top down, closest to the motor. It's current orientation is showing the turbine stage\s side.

3. A final diffuser\directional plate (static)

2. 4th Stage "shell" or assembly holder.

[Stages - 4 being closest to the motor and 1 being furthest from the motor.]

4. The combined assembly for stages 2, 3 & 4. With the 2nd stage assembly being empty. So just a shell like item 2. Except it's sat on top of stage 3.

5. a blade\disc\fan for either stage 1 or stage 2.

6. Same as 5 above.

7. Collection of spacers & washers. 2 spacers appear to be the same height and possibly the same diameter, i.e. identical.

You've popped off the 4th stage assembly completely - that's item #2. The 2nd picture shows one of the internals of it (a fan\disc). The other fan\disc belongs in the 3rd stage of which you can see the inside of top (item #4).

The loose order of reassembly would be

- item 4,
- place 5 or 6 in it (with one of the 2 identical spacers in the group #7). I'm making the assumption that #5 & #6 are actually identical.
- #2 on top of that.
- followed by the remaining disc (#5 or #6) and with one of the 2 identical spacers in the group #7.
- #3 in the orientation it is shown with the 2 pins facing upwards.
- Turn #1 upside down so that the tangential exit is on the right (picture currently show it to the left) and place it on top, so that the 2 pins on #3 engage with the 2 holes in #1.

Motor assembly should then sit on the top with the spindle sliding thru all the holes.

You can obviously put the motor assembly down (upside down with the shaft facing upwards) and put everything on in reverse.

The big question now is how do the discs\washers\spacers go.

In the 2nd picture - item #4 (looks a bit like a metal tiffin box), if you remove the top of it (carefully) exposing the 3rd stage - you will see how the blade\disc, spacers & washers go together.

Hopefully not as clear as mud.

Dibs

 

[deema]

Cheers Dibs, that’s really helpful. Did I mention that the unit wasn't designed to be taken apart! The bearing that had disintegrated was located directly behind the 4th stage and was held in place by a cage that was riveted through the 4th stage cover. The shaft of the motor runs through the entire assembly and to get into it I had to knock the shaft out......with everything suddenly coming apart!!

One of the spacers is slightly shorter than the rest, I believe it came from the 4th stage.

I’ve managed to get the other stages apart today, so I now know the orientation of the fans. However, the spacers and washers were just rattling around inside as you’d expect. Looking at the witness marks, it seems to be fan, washer, spacer, washer, fan. I had to open up the other stages as I needed to find the remains of the bearing and to get at the washers and spacers to re-assemble.

The two bearings needed for the motor are a 608RS for the top of the motor and a 6000ZZ for the bottom against the 4th stage.......big heavy duty bearings.....tongue in cheek........my skateboard had better bearings nearly 40 ears ago!

 

[Dibs-h]

I would suggest powering it up before you go the whole hog and bolt it back in. Just in case their is an orientation of the blades, i.e. balancing thing going on.

Might be an idea to lay to blades on top of each other to see how the "cut outs" on the edge are laid out and maybe stagger them by 90 degrees or something - to try and balance them out.

 

[deema]

The two bearings finally arrived so I can not start to try and assemble it back together. It’s very very this tiny stuff, so very easy to bend and distort.
First off, the bear8ng needs to be popped back in. The retaining cage was completely mangled when the original bearing disintegrated. The cage was originally a stamping, but the exact form wasn’t recognisable. After attempts were made to create the original shape, time out was called and the cage was just squashed flat and the holes extended to make it fit. The problem with trying to create the original shape is that it touched the windings.

The cage was held originally by rivets that fit into studs that hold a plate underneath the aluminium casting. The original rivets were drilled out and new ones used to secure the assembly.

The whole assembly was then placed into the warming oven of the Aga and after 30 minutes the motor shaft pushed back into place.

The rest of the compressor assembly can then be assembled. The sequence which I didn’t photograph, as it took four attempts to get it right is
Small spacer, washer, fan, washer, long spacer, fourth stage cover which is slightly thinner than the others. The best way to get the body covers back on is to warm them up (aga warming oven worked perfectly) and then they can be pushed on with hand pressure. The next stage is then washer, fan, washer long spacer, third stage cover. The second stage is the same. The first stage is washer, fan, locking washer which is a press fit (it’s thicker than the other washers) and needs to be pressed to ensure the fans don’t slip on the shaft. A nut then secured everything before finally putting on the bottom cover. The assembly should rotate freely as each stage is assembled and when finally complete.

A new top bearing was then warmed up and popped on. I will pop a picture of the assembly up tomorrow.

 

[deema]

This is the unit with the motor installed

Next the field windings are popped back on top.

The plastic housing then goes on that holds the two brushes. The brushes have a really long length for good longevity. Two convenient holes in the top allow thin flat headed screwdrivers to hold the brushes back when putting it on. Two bolts hold everything together. The top bearing needs a little encouragement to seat in the housing. There is a thrust washer at the top of the seating.

The motor cooling fan sits on top. It’s important to get it the right way up, you want the air blowing down over the motor. The fan is well made and needs pushing down onto the splined end of the shaft.

The plastic unit that covers everything clips around two lugs, the clips spread apart laterally but won’t stretch very far.

 

[deema]

The assembled compressor mounts on three bolts in the casing. It has a rubber gasket underneath. The aluminium pipe that couples the compressor to the body of the casing is a very tight fit. It just sits in the aperture of the exhaust with a rubber O ring that’s a very loose fit. The connecting pipe has a two holes, one is a bypass allowing air to escape when the gun trigger isn’t pressed, it allows air to escape even when the gun is in use....this is a very bad design and a simple pressure relief valve would have been a professional solution. The other is threaded and a cap head screw from the base passes through an aluminium block and screws into it to locate it.

The air not the inlet of the compressor is fed from the filter, through a pipe and into a baffle box at the back of the unit. It’s just a foam sandwich, and not very technical despite all the hype about the Q units being engineered for sound reduction. I certainly wouldn’t pay for it again. Interestingly I couldn’t really hear much difference with the baffle on and off!

 

[deema]

After attaching the rest of the covers it was time to give it a try. Worked perfectly, in fact I now believe the bearing had been going for some time as the outlet now runs significantly cooler and the air pressure is higher.

The two SKF bearing cost me c£10. A replacement motor would have been circa £265 and you can’t get one from Fuji / Axminster who are their UK exclusive agents.