Diagnosable remotely - YES
Fixable remotely - MAYBE
If the machine is cycling but no sample is coming out of the product outlet, the only really viable scenario is that the product is flowing back into the reservoir because the check valve is blocked.
Firstly, check whether the sample IS being pumped back into the reservoir. 6ml sample will be drawn in, then flow back into the reservoir to the level will go slightly down and up again with each stroke. If this is the case, the check valve is blocked and is stopping the check valve ball from seating properly.
If the product is not flowing back into the reservoir, the only other explanation is there is a massive leak somewhere that has not been noticed. This should be checked before assuming a check valve blockage.
SOLUTION:
- Ask the customer to remove the reservoir (use stopper), then remove as much sample as possible from the check valve inlet (eg, using a pipette). If the machine is fitted with a prime valve, this can be used to flush old problematic sample away.
- They should then attempt to wash the check valve inlet area with a suitable solvent. If a bio-application, that should be NaOH or Hellmanex. If not, any suitable solvent such as IPA will work.
- The cleaning agent can be sprayed or poured into the check valve inlet.
- The priming tool should then be used to "agitate" the check valve ball.
- The HP line going into the bottom of the pump head can be removed for this task to help aid flow through the check valve inlet and wash away the blockage.
If the block cannot be cleared in this manner, full disassembly of the check valve assembly is required. It is unlikely that the customer will be able to do this themselves (in most but not all cases), so will require an engineer call out to disassemble the check valve assembly and clear the blockage.
It is worth having a new check valve ball and spring for the site visit, as the check valve ball could be the issue. Recommend the customer orders these parts with the site visit if that is the course of action chosen.