# I'm trying to restore an old air compressor, but probably I need help



## netrap (9 mo ago)

Hello everyone, do you guys know what is this? Maybe it's a safety valve? (Figure 1-A and figure 1-B). Because the pressure switcher has one way. I guess near this thing there was the pressure gauge of the tank once. I need to buy the gauges as well. The gauge of tank has a bigger scale, right? Like this:








While the other pressure gaunge, for outcoming air (?), is smaller and has a smaller scale, right? Like this:








But fondamentally they do the same thing, I could also put two equal gauges, it will be the same, am I right?

Thanks in advance.


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## stevon (Mar 5, 2019)

Netrap,

I don't know but it looks like an adjustable safety release valve to prevent over pressure of the tank and catastrophic rupture. Modern safety valves usually have a pull ring and are preset for single or double stage compressors. The tank "working pressure, on a tag or stamped on the tank will tell you what pressure safety valve to buy. modern aftermarket manifolds come with one, for liability reasons I guess.

















Stephen


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## stevon (Mar 5, 2019)

Netrap, 

Do not remove it unless you are going to replace it with another safety valve somewhere. It doesn't have to be in the same place but needs access to all of the tank pressure.

Stephen


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## netrap (9 mo ago)

Hi Stevon, thanks for reply. I removed the paint that was covering the tag, so now I know the manufacture's name. GIANESI. There are also other informations stamped on the tank, and they are: B107 43 • 1 • 10 • 1968 • 12 I think B107 43 is the tank model, 1.10.1968 is the date (dd.mm.yyyy), and 12... I have no idea, maybe the pressure? 12 Bar? Isn't that too much? And other 5 numbers that I think it's the registration number.
I also think it's a safety valve, but on the moderns one there is a "ring" where you can put your finger inside and pull to release the air. But this one it can be pulled or pushed, is it possible that this is an automatic safety valve? There is a spring inside and I think it's possible to regulate it, maybe it's just like the pressure switch, when the tank reaches the same pressure at which the safety valve was set, it is automatically activated by releasing the air. I'm not an expert, just guessing, is this possible? Or maybe it's just stucked, but it looks fixed to me. Tomorrow I'll try to remove it and see how it works. So If I want to put a modern manual safety valve, assuming that that one is automatic, can I change my one way pressure switch with a four ways pressure switch? Mine is like this:









Can I use this?








If I will install this, do I have to remove the tank manometer mounted to the pressure switch, and put a screw instead? Or can I have both?

Thanks in advance.


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## iowagold (Jan 22, 2020)

sure run both!


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## stevon (Mar 5, 2019)

netrap,

You can have both. I don't know what those numbers stamped mean me being in the US, I know that 12 bar is equal to 175 psi so you would be safe with a safety valve of 150 to 175 psi, they come in standard ranges in the US for single stage compressor tanks (150 to 175 psi) and 200 psi for two stage compressor tanks. They never are used unless there is a motor control failure and tank is pumped up beyond the "safety" or "rated" value. You can install safety valve in the tank manifold or a bung on the tank. Single stage compressors generally only go up to 150 PSI max or 10.3 bar and they don't produce as much CFM at that high pressure. 
Take the plugs out of the manifold and at least install the safety valve, a gauge is optional in another port.

Stephen



netrap said:


> Hi Stevon, thanks for reply. I removed the paint that was covering the tag, so now I know the manufacture's name. GIANESI. There are also other informations stamped on the tank, and they are: B107 43 • 1 • 10 • 1968 • 12 I think B107 43 is the tank model, 1.10.1968 is the date (dd.mm.yyyy), and 12... I have no idea, maybe the pressure? 12 Bar? Isn't that too much? And other 5 numbers that I think it's the registration number.
> I also think it's a safety valve, but on the moderns one there is a "ring" where you can put your finger inside and pull to release the air. But this one it can be pulled or pushed, is it possible that this is an automatic safety valve? There is a spring inside and I think it's possible to regulate it, maybe it's just like the pressure switch, when the tank reaches the same pressure at which the safety valve was set, it is automatically activated by releasing the air. I'm not an expert, just guessing, is this possible? Or maybe it's just stucked, but it looks fixed to me. Tomorrow I'll try to remove it and see how it works. So If I want to put a modern manual safety valve, assuming that that one is automatic, can I change my one way pressure switch with a four ways pressure switch? Mine is like this:
> View attachment 11676
> 
> ...


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## netrap (9 mo ago)

Hi, thanks for the reply, I ordered the parts from Aliexpress, so I have to wait now, but I think I'll need your help with the electric engine cables' scheme. Thank you all.


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## stevon (Mar 5, 2019)

netrap, 

Your tank looks pretty old in the pictures, I would hydrostatic test it to see if is safe, see one method in the video below:





__





how to hydrostatic test an air tank - Google Search






www.google.com





Stephen


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## stevon (Mar 5, 2019)

netrap,

You don't have to replace the pressure controller, just add the manifold part, they are cheap:









Air Compressor Pressure Valve Switch Control Manifold Regulator Gauges Tool C# | eBay


Air Compressor Switch Bracket Air Pressure Regulator Valve Pump Parts. Applicable compressor type: Piston compressor. 1 Safety valve (copper). 1 Red cap (plastic). Because, our prices are unable to include above fees, as the custom policies are different in every territories.



www.ebay.com





Stephen




netrap said:


> Hi Stevon, thanks for reply. I removed the paint that was covering the tag, so now I know the manufacture's name. GIANESI. There are also other informations stamped on the tank, and they are: B107 43 • 1 • 10 • 1968 • 12 I think B107 43 is the tank model, 1.10.1968 is the date (dd.mm.yyyy), and 12... I have no idea, maybe the pressure? 12 Bar? Isn't that too much? And other 5 numbers that I think it's the registration number.
> I also think it's a safety valve, but on the moderns one there is a "ring" where you can put your finger inside and pull to release the air. But this one it can be pulled or pushed, is it possible that this is an automatic safety valve? There is a spring inside and I think it's possible to regulate it, maybe it's just like the pressure switch, when the tank reaches the same pressure at which the safety valve was set, it is automatically activated by releasing the air. I'm not an expert, just guessing, is this possible? Or maybe it's just stucked, but it looks fixed to me. Tomorrow I'll try to remove it and see how it works. So If I want to put a modern manual safety valve, assuming that that one is automatic, can I change my one way pressure switch with a four ways pressure switch? Mine is like this:
> View attachment 11676
> 
> ...


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## netrap (9 mo ago)

Hi, thank for reply. I watched the video, pretty easy, but I don't have that water tool, just a normal flexible tube, beside this I don't have yet the manometer for the tank. Now I'm removing all the external rust and is not that bad, there is not heavy rust, in some area the are some deeper zones, but they are not that bad. It would be batter removing the rust with a sandblaster but I don't have one, and this is the only compressor I have so I'm cleaning the thank manually and with a grinder. I will use a primer rust converter before painting it, so I'll block the remained rust. I don't get why you suggested to buy a manifold part, I have the pressure controller, it's old but it's in a good shape. This is not my compressor, but is very very similar, and the pressure controller is almost identical. I noticed that the inside of the thank is very dirty, maybe rusty, any advice how to deep clean it? Another thing, the max pressure of the tank is 12 bar, that means I have to set the pressure switch lower than that, like 10 bar, right? Or I have to calculate also the engine power? That is 1 HP. Maybe the engine is not power enough to reach 10 Bar? Thanks in advance.


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## netrap (9 mo ago)

@stevon Probably you wanted to reply here: Hard to find valve for copressor (UK). I don't know why it was in my alerts.


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## stevon (Mar 5, 2019)

netrap,

Tanks rust from inside, that's what I worry about. I restored an older tank my self and used this "rust Destroyer" in spray cans for outside of my tank, haven't pressure tested my tank either (probably should have). I just tapped around with a small hammer and listened. I think a 10 bar safety valve will work for you, just remember not to pump up to 10 bar, set your cutoff pressure to less on electrical pressure regulator. Single stage pumps generally work best at a top pressure setting of 135 psi cutoff,10 bar is 150psi and no point going up to that. At 10 bar pressure, the pump demands the most HP and that will show with the highest maximum amps drawn, you will see this with an ammeter. Physics doesn't lie, to produce a given HP from an electric motor, amps over voltage reveals the real HP generated. If your motor plate says FLA is 6 amps at 230 volt then you have a 1 HP motor. Say your load is 1 HP, 6 amps will be drawn on any motor at that load. Even if you are using a 1/2 HP motor with a 1 HP load 6 amps will be demanded on the motor and motor will try to provide that but it will overheat/stall and if not turned off will burn out the wiring inside or trip the thermal overload. If an overloaded motor starts stalling, it will start to draw even more current until something gives, circuit breaker, thermal overload, wires burning etc. That's why you need to have a nameplate stating the FLA. that rating tells you what a given motor can produce in actual HP and where you dare not go beyond for more than a few seconds. An ammeter tells you what is going on and what limits you are crossing or not crossing, a very useful tool. Lets say the driven pulley is too large, this would increase the pump rpm which requires more HP. So this would demand more HP from the motor seen as current draw. Lets say that now 10 amps are seen on your 1 HP motor, that means that the load requires a 2HP motor and is demanding that from your motor. We see with an ammeter what is going on and that overheating, tripping breaker, motor stalling would make sense in that scenario. We can conclude that the chosen drive size pulley is suspect









































Stephen



netrap said:


> Hi, thank for reply. I watched the video, pretty easy, but I don't have that water tool, just a normal flexible tube, beside this I don't have yet the manometer for the tank. Now I'm removing all the external rust and is not that bad, there is not heavy rust, in some area the are some deeper zones, but they are not that bad. It would be batter removing the rust with a sandblaster but I don't have one, and this is the only compressor I have so I'm cleaning the thank manually and with a grinder. I will use a primer rust converter before painting it, so I'll block the remained rust. I don't get why you suggested to buy a manifold part, I have the pressure controller, it's old but it's in a good shape. This is not my compressor, but is very very similar, and the pressure controller is almost identical. I noticed that the inside of the thank is very dirty, maybe rusty, any advice how to deep clean it? Another thing, the max pressure of the tank is 12 bar, that means I have to set the pressure switch lower than that, like 10 bar, right? Or I have to calculate also the engine power? That is 1 HP. Maybe the engine is not power enough to reach 10 Bar? Thanks in advance.


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## netrap (9 mo ago)

Hi, sorry if I respond only now, but i was busy, plus I did some progress. I finished with the tank and I've opened the pump engine. I cleaned everything and already bought the specific oil and made the new internal gaskets with the paper sheet, I only need the external gaskets, the red ones for the screws, apparently hard to find where I live, they are in steel fiber or something, I think I will buy them on Aliexpress. In the next days I will upload the photos of the electric motor, there is a broken part but I think it's not a problem. You think it's better to set the pressure switch to 8 bar? Since the security valve it's 8 bar and the manometer background starts to become red after 8 bar, plus the engine that is a bit weak. Thanks in advance. EDIT: Unfortunately after I've opened the engine I forgot to take pictures and now I don't know the position of the segments of the piston since I change their position when I cleaned the piston. I read that the pump engine it's like a 4 stroke engine, so they should be at 120 degree or something, there are tree of them. Do you guys know exactly what should I do? Thanks.


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## stevon (Mar 5, 2019)

netrap, 

I would think 9 bar max (130psi) would be fine, you can always back it down if needed. Most single stage compressors seem to be set around 125 psi shut off pressure. The ring positions on the pistons aren't hypercritical in an air pump application, as long as the ring gaps aren't all lined up. Question: why would you mess with the pump anyways? curiosity? I would only be messing with pump if there was a problem eg honing bore (to polish out scratches), a piston (replacing a broken piston) head gasket (a leak) or because of a particular issue with the pump otherwise I wouldn't touch it. they are simple machines and need little maintenance other than filters and oil. Only excessive wear or broken parts requires doing anything to a pump IMO. If there is metal in a gasket I don't think that is absolutely necessary for a compressor there are no 1600 degree flames going through it like in a gas engine, lol, fish paper or similar gasket material should work just fine. Enjoy your project!

Stephen


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## netrap (9 mo ago)

Hi, I opened the pump engine because since there wasn't the air filter, some bugs went in the head of the engine and created their nest, it was completely clogged by something like cotton/wool/trash and their dead body, furthermore there was residual oil engine near all the removable parts of the engine (carter, head, and the thing that link the pulley to the connecting rod). Also the oil inside was "solid", only 1/3 of the oil was liquid (totally black, the new one is yellowish) the other 2/3 was sludge stucked on the bottom (like 2 or 3 cm), even between the head of the piston and the top of the inside head there was like 3 mm of solid oil mixed to very very little rocks, so the valves were also "stucked". But the engine wasn't blocked, just heavly dirty. I found those red gaskets broken, I decided to replace them so it will be just like it was in origin, I bought them on Aliexpress so I'm waiting now. Now I have two problems: 1) the pressure switch i bought on Aliexpress use a 10mm connector, but my check valve is 1/8, so I need an adapter for it, I bought this one: Brass Pipe Hex Nipple Fitting Quick Coupler Adapter M14*1.5 M20*1.5 M10 16 18 22 27 1/4 Pressure gauge conversion copper joint|Pipe Fittings| - AliExpress A M10x1 B G1/4 BSP then I will use another adapter for 1/4 to 1/8. I hope it's the right one.
The second problem is that both the bearing of the electric motor are very slow, I need to replace them, can't even open them because they have unremovable metal shield, I need an extractor to remove the pulley from the motor and the two bearings but I don't have one, I'm trying to create an home made one. Thank you.


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