Leaking AIV on pump. Question: If the cartridge is replaced, but the mechanical valve is defective, will it harm the new cartridge?
The cartridge most likely will not be damaged.
What do you mean with leaking AIV?
I assume that you mean an external leak and you can see solvent leaking out between the AIV and the pump head?
I just ask because the AIV cartridge has two functions.
One of it is to provide a leak tight connection between these two parts (AIV valve and pumphead).
This is just done by the gold seal layer on both ends of the cartridge.
This sealing function most likely is compromised due to mechanical reasons.
The gold layer is relatively soft and gets compressed and so that it looses its ability to compensate small scratches.
Re-tightening the AIV while it is under pressure (pump is active) speeds up this effect.
But this sealing function also very much relies on the surface condition of the counterparts.
In case of larger scratches on the inner surface of the pumphead or the AIV, it can happen that the gold seal on a new or newer cartridge cannot compensate these scratches.
Therefore it is important also to check the condition of the counterparts from time to time.
The second function of the AIV of course is to verify that the flow (pressure) that is generated in the first piston chamber only can move towards the second piston chamber.
This is done by its internal ruby ball that gets pressed into the ceramic seat as soon as the pressure in piston chamber 1 increases.
In case this function is compromised you can have a back flow and you typically would see a large pressure ripple and reduced or almost no flow into the system.
These would be an internal leak without solvent leaking to the outside.
An AIV cartridge therefore potentially can always get damaged during the installation of the AIV.
Do not overtighten it to prevent harm on the internal parts.
Verify that the counterparts are free from particles and scratches.
If this is checked, you have a very low risk of damaging it.
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