Air in the lines?.. I have a 15yr old "Dimension One" spa. I replaced the old spa pack with a new one and cannot get the heater to work. it appears I have air in the lines...?? I have two filters, one small and one larger one. the smaller one (located on the left side) appears to be sucking all the water and in about 2min. sucks air and the pump starts to cavatate. the filter on the right is where the skimmer inlet is. I don't seem to have any suctions or pressure out of the two holes in the skimmer. the filter sits on a 1" (approx.) x 12" tube. the old spa pack used to have an ozoneator but I didn't get one with the new one. there is a 1/4" tube that runs from the bottom of the filter(?) to where the old ozoneator was, I plugged it off. there was also a 1/4" tube that ran from the suction side of the pump to the heater(?).. I plugged that off also because it has no place to go on the new system. I just can't get constant flow it seems because of this air problem. from what I understand that is why the heater wont come on. any suggestions on how I can bleed the air out of the system. ??.. can't seem to find anyone who has a diagram of the plumbing of an old dimension one spa....any help would be appreciated..... Thank you....Ron

You can bleed the air by loosening any of the unions or the drain plug on the pump. This works best with the pump on high. However, if you're getting good water flow until the one filter starts pulling air, you may have another issue. Try running a hose into the line that's not pulling water, or even using a plunger over it.

It's also hard to tell exactly how your pack is installed (suction side or pressure side). If it is installed on the suction side you will need a flow switch instead of the pressure switch that is probably installed on it.