Hydrovane HV02 bypassing at 90psi

[Markusparkus]

I've just picked up an old HV02, running fine but it only builds pressure to 90psi then it changes tone and wont give me any more pressure. Is there a way to adjust this to give me a bit more?.. the trouble is compounded when the electric pressure switch has to be adjusted down to cope wuth this and doesnt switch back on till the pressure is even lower... Hope someone can point me how to increase this running pressure...

 

[m_c]

Some Hydrovanes were only designed to run at 7 bar (~103psi), so it could be the pressure relief valve has gone a bit weak.

If it is a 7bar unit, then upping the pressure isn't possible, as from my understanding there were differences with the internals to allow the higher pressure.

 

[Markusparkus]

Many thanks, is there any way I can tell whether this is a 7bar unit? if its not, do you know how I can change the pressure?

 

[angellonewolf]

Hydrovane HV02 Air Compressor 8 CFM, 10BAR, 240V 75L

This Hydrovane HV02 Air Compressor 8 CFM, 10BAR, 240V 75L compressor was swapped out for a larger unit from a dentist in Chichester - Hampshire.

airlinkcompressors.com

this yours ? if so should be 10 bar ?

 

[Markusparkus]

Many thanks, Yes, it looks very similar, I'll get a picture for you in the morning... so do you know if I can adjust the pressure up somehow?

 

[angellonewolf]

i dont but the more info you can provide will help people give you more help so make model number a pic of the plates on the unit

 

[m_c]

If it is a receiver mount, then I'd expect it to be a 10 bar unit.
The problem with identifying the earlier models, is the pressure was simply marked on the label by circling the relevant pressure using a marker pen. By now it's likely faded/worn off.

Given the unknown history, I'd suspect it was cheap for a reason.
You can't adjust the pressure of them, as they are a pretty simple rotary vane. There is an internal pressure relief valve, but that sounds like an air leak when venting.
If the change of tone isn't air venting, then there's a good chance that it's simply worn out, especially if it hasn't been maintained with the correct oil.

They're not that hard to strip, which will give a far better indication of it's condition, and you check for any blown seals.

 

[Markusparkus]

Its been lying around in need of a motor, but coupled up now and working nicely but for the pressure. here is a pic of the unit, and as you describe, its on the data plate (my apologies for not looking here)... max press 11bar. Its only giving me about 6 bar, so way down. Its moving enough air, just a valve popping off inside and not giving me the pressure.. I guess it needs stripping down...

 

[angellonewolf]

im not going to say how to make ajustments to the black unit (the one with the dial on it as only done iot once)

there will be a screw on to to remove the cover and you should have 2 screws one for higher setting (but this also does the lower as well) and the other changes the makes changes to the higher settinmg

i think i have this right but wait for some one to give more info

 

[Markusparkus]

The high / low pressure electrical is working fine.. I can adjust it to start and stop the motor as needed. Its the hydrovane unit itself... its all fine until about 90psi (6bar) then the tone changes, and no more pressure results. I need this to be a bit more. As per the thread above, it seems its a 10bar unit, so I'm guessing there is a worn valve somewhere inside... what this looks like or how to strip this down still remains, but I'm keen to give it a go. Its making so much more air than the old unit its an amazing bit of kit and worth the work I'm sure.

 

[angellonewolf]

There a capactor in there some where that's where I had my problem but that was blowing Fuses if the capactior is not right can make meny different problems

 

[angellonewolf]

I'm.assumimg in thr big black box on the right

 

[m_c]

It's not an electrical problem.

Stripping them is fairly easy.
Basically start with the air filter, and keep going. They're not a complicated design.
Make sure you drain the oil first, and then be prepared for more running out when you start unbolting metal bits.

 

[Markusparkus]

OK many thanks for the encouragement. I'll see if I can find some time over the weekend. Thanks all for your input, I'll post again with my findings

 

[8ob]

Not sure if this model is fitted with a thermal bypass, my 66 had similar issues and it turned out to be the problem.

Bob

 

[Markusparkus]

Thanks Bob, I dont know whats inside. but I will get to the bottom of it, its a brilliant bit of kit..