Have HVAC Questions? Ask an HVAC Expert for Answers
Is your pump running? when was the last time you cleaned/backwashed the filter?
What's the brand & model number of your unit? do you have a multi-meter? if you want to troubleshoot this there's not a lot you can do with a meter in most cases
Aside from the filter questions there's not much I can offer except for some help with onsite troubleshooting.