johnnyb
Established Member
what a great result. extreme patience paid dividends!. slightly let down by Fujitsu q engineering tbh what a load of hype!
Fuji HVLP Compressor Failure - Help and Repair WIP
- Thread starter deema
- Start date
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Dibs-h
Established Member
Deema - really chuffed for you that you got it going. 
AJB Temple
Finely figured
Good thread. Thank you. As a matter of interest, would you buy Fuji again?
Well done Deema, good result and interesting to see the inside of the unit. =D>
Seeing the dedication you put to this I knew you would be an Aga man. :lol:
My take on the "Would you buy Fuji again" I don't think any of the other offerings would be any better, but maybe worse if any cheaper?
Seeing the dedication you put to this I knew you would be an Aga man. :lol:
My take on the "Would you buy Fuji again" I don't think any of the other offerings would be any better, but maybe worse if any cheaper?
With the help of Sideways the research we did seems to suggest there are very few actual manufacturers of the compressors used at the heart of these type of units. Looking at the engineering of the actual box it sits in your not getting IMO anything more buying a top end brand than the cheapest.
The compressor used in this unit itself has been really value engineered. The windings are not epoxied which I would expect on any high end motor. The bearings were cheap no name ‘made in China’ and are as small as possible. They could have easily fitted larger bearings to make the unit last longer. The brush housings are horrible things. The good bits were the quality of the cooling fan and the length of the brushes
There is a built in life reducing feature! The bypass is letting air escape all of the time which in turn is heating up the connecting aluminium pipe and by consequence the lower bearing, motor windings and the hose. On the five stage units it appears they get so hot they are melting the standard hose in some cases. If the bearing gets too hot the grease melts out and the bearing fails which is what I think happened to mine.
I’m actually thinking of building my own air bypass for the unit which is actuated when the presume builds up or on the current drawn through the motor. Still thinking about it. The high end Graco units claim to have an auto stop on the compressor when the gun isn’t being used, but whether this alleviates the need for the constantly open bypass I don’t know. The main reason for wanting my own bypass system is that I will get higher pressure / CFM if it’s not open when the gun is being used and probably about the same performance as a five stage unit from my four.
So if I were looking for a unit again, I would probably buy a compressor and the gun separately. I’d buy the cheapest five stage unit I could find and again buy the Fuji gun. The Fuji gun has a pressurise gravity cup that helps with spraying thicker material I believe.
If I were to buy an all FUJi system I wouldn’t personally buy the Q, I’d buy the cheaper Mini system, it’s exactly the same unit I believe minus a bit of foam.
If I wanted a unit for my shop only, I’d probably buy a compressor and really top end gun with either a RPLV or LPLV Cap. I’m still researching this, as I’m thinking of moving to a static system.
The compressor used in this unit itself has been really value engineered. The windings are not epoxied which I would expect on any high end motor. The bearings were cheap no name ‘made in China’ and are as small as possible. They could have easily fitted larger bearings to make the unit last longer. The brush housings are horrible things. The good bits were the quality of the cooling fan and the length of the brushes
There is a built in life reducing feature! The bypass is letting air escape all of the time which in turn is heating up the connecting aluminium pipe and by consequence the lower bearing, motor windings and the hose. On the five stage units it appears they get so hot they are melting the standard hose in some cases. If the bearing gets too hot the grease melts out and the bearing fails which is what I think happened to mine.
I’m actually thinking of building my own air bypass for the unit which is actuated when the presume builds up or on the current drawn through the motor. Still thinking about it. The high end Graco units claim to have an auto stop on the compressor when the gun isn’t being used, but whether this alleviates the need for the constantly open bypass I don’t know. The main reason for wanting my own bypass system is that I will get higher pressure / CFM if it’s not open when the gun is being used and probably about the same performance as a five stage unit from my four.
So if I were looking for a unit again, I would probably buy a compressor and the gun separately. I’d buy the cheapest five stage unit I could find and again buy the Fuji gun. The Fuji gun has a pressurise gravity cup that helps with spraying thicker material I believe.
If I were to buy an all FUJi system I wouldn’t personally buy the Q, I’d buy the cheaper Mini system, it’s exactly the same unit I believe minus a bit of foam.
If I wanted a unit for my shop only, I’d probably buy a compressor and really top end gun with either a RPLV or LPLV Cap. I’m still researching this, as I’m thinking of moving to a static system.
I use a remote control for the power on my unit so don't have to go to the unit to turn it off, probably helps with the overheating you have experienced as it's never happened to my unit, even after spraying four wardrobe doors at once using a remote pot of five lites capacity, but interested in any improvements you come up with for the bypass, keep us posted.
johnnyb
Established Member
I'm suspicious the original 3 stage turbines were fine and durable but as the boundaries were pushed to 4 and 5 stage overheating becomes a menace.
Robbo3
Established Member
Excellent work & very interesting.
I worked for a company that made its own brush motor. They bought in ready machined shafts & all the component pieces to turn out about 500 motors a year.
I worked for a company that made its own brush motor. They bought in ready machined shafts & all the component pieces to turn out about 500 motors a year.
I think I’m going to add a pressure gauge to the device so I can see what the actual output pressure is. I am also going to add a simple pressure relief value when I find out what the working pressure actually is and block up the air bypass hole. This will give me better performance as well as reducing the heating. Im probably also going to add a simple temperature monitor and a relay to turn off the motor should the temperature exceed 90 degrees to protect both the motor and the bearings. These are all classed as Jelly Bean parts and for anyone to buy them they should see change out of £20~£30. For me, I think this is an easy investment decision, the cost of new compressor is c £260.
If I were Fuji I would expect to be paying less than a few pounds for the bits, which would really enhance the perceived value of the unit as well adding some basic protection to make it last longer.
It’s not that the design has been ‘pushed’ by moving to multi stages, it’s just the design hasn’t taken into account basic preventative maintenance philosophies to design out over heating.
If I were Fuji I would expect to be paying less than a few pounds for the bits, which would really enhance the perceived value of the unit as well adding some basic protection to make it last longer.
It’s not that the design has been ‘pushed’ by moving to multi stages, it’s just the design hasn’t taken into account basic preventative maintenance philosophies to design out over heating.
Deema
Not trying to be critical, but I look at this a different way, the pressure to a certain extent is irrelevant, the important bit is airflow, it's just that when the airflow increase's the pressure has to go up (Bernoulli's theorem) this in turn will increase the temperature of the air which I find a bonus as it heats the paint and it dries quicker.
My unit has never overheated or cut out due to heat even though I use it in the South of France in +40degs at times, I think your unit must have been faulty for some time?
Not trying to be critical, but I look at this a different way, the pressure to a certain extent is irrelevant, the important bit is airflow, it's just that when the airflow increase's the pressure has to go up (Bernoulli's theorem) this in turn will increase the temperature of the air which I find a bonus as it heats the paint and it dries quicker.
My unit has never overheated or cut out due to heat even though I use it in the South of France in +40degs at times, I think your unit must have been faulty for some time?
Thanks Mike, your thoughts are helpful and appreciated.
I do believe the bearing has been going for some time. The bearing rated to run below a max of 90 deg C if memory serves. The bottom bearing is a ZZ / metal shielded for low friction and I’m sure that the grease just over time with the ’normal’ higher temps just ran out. the outlet has always been too hot to touch with bare hands after a few hours running. The lower I can keep the temp, the better the longevity.
The bypass is just a hole so the compressor is always running when switched on. What Im planning on doing eventually is blocking up the bypass hole, using a pressure relief valve as a ‘safety’ blow off, a simple cheap thermal cut out to ensure the temp doesn’t rise too high and finally a very simple either pressure or current overload to switch off the compressor when the gun trigger isn’t pulled. The pressure gauge is so I can monitor the ‘health’ of the compressor and ensure it’s pumping out the right amount of air. If my repair isn’t up to scratch the stages may start to slip on the shaft loosing pressure. If sounds a lot I know, but it’s about an hours work and £20 of bits once I’ve found the working pressure.
The pump only has rated figures for suction and I’m not cleaver enough to work out what that transpires to in terms of outlet pressure.
I do believe the bearing has been going for some time. The bearing rated to run below a max of 90 deg C if memory serves. The bottom bearing is a ZZ / metal shielded for low friction and I’m sure that the grease just over time with the ’normal’ higher temps just ran out. the outlet has always been too hot to touch with bare hands after a few hours running. The lower I can keep the temp, the better the longevity.
The bypass is just a hole so the compressor is always running when switched on. What Im planning on doing eventually is blocking up the bypass hole, using a pressure relief valve as a ‘safety’ blow off, a simple cheap thermal cut out to ensure the temp doesn’t rise too high and finally a very simple either pressure or current overload to switch off the compressor when the gun trigger isn’t pulled. The pressure gauge is so I can monitor the ‘health’ of the compressor and ensure it’s pumping out the right amount of air. If my repair isn’t up to scratch the stages may start to slip on the shaft loosing pressure. If sounds a lot I know, but it’s about an hours work and £20 of bits once I’ve found the working pressure.
The pump only has rated figures for suction and I’m not cleaver enough to work out what that transpires to in terms of outlet pressure.
As far as I know outlet pressure should not be above 10psi, as I said outlet speed of air and pressure are interrelated and only if you increase the outlet diameter can you decrease the pressure for the same CFM.
Interested in what you propose, please keep us informed.
Interested in what you propose, please keep us informed.
