The contactor is a switch that is used for high power applications. In this system it is normally closed until power is called for by the heaters through the PC board. Acura Spas expert Joel told me the chatter meant that there was something wrong with the pressure such that it could not decide whether to stay open or closed. The situation meant that the pump could not be run on low or it would burn out.
The pump runs on low to filter the water and also during the heating cycle. It is very quiet on low which is nice. It is manually switched to high to have the jets more active for exercise in the spa or for the theraputic action of the water.
Joel suggested I read about spa hydraulics and get back to him after I did some troubleshooting on my own, including lowering the pressure on the pressure switch, cleaning the filter etc. Of course I had already cleaned the filter so I got out the new one that was included with the spa sale to try to install it and it didn’t fit! I turned out that they bought a slightly larger filter and got it to fit by removing one of the rubberized rings on the unit’s end. I don’t think it matters whether the ends are attached. But I ordered a new set that I think are the correct size, just in case.
On a pool the filter housing is airtight, but on a spa it is not. It took me some time to figure that out and stop worrying that something was missing from the filter housing. It was again videos from you tube that demonstrated changing a filter and the components were all the same ones I have. So no pressure was being lost in the filter housing.
I lowered the pressure switch as Joel instructed but that had no effect, and I bypassed it with a jumper wire to check to see if it was bad, although Joel said he hardly ever sees them go bad by themselves. That was not the problem.
I wondered if there was a leak on the suction side of the piping and noticed a bit of water under the spa after I had run the pump on high so I started to take off the siding and the wire and the insulation realizing that if there were a leak it would be pretty hard to get to! But the pipes were completely dry. Joel told me a leak would not cause this problem anyway. I just got the idea from reading about suction side pressure problems.
Finally I was playing around with the topside control and decided to set the time which worked, and then I set the temp on the pump and immediately the contactor stopped its chatter! I was really surprised. But it seems that the temp set at 46 could not decide whether to call for heat or not. By setting the temp above the temperature of the water–about 70, the heaters were able to answer the call for heat and the switch could operate normally.
I was so relieved! I still had to test whether the heaters were working, they both had power to them, but I turned off the power to reinstall the cover. When I did that I found another wiring diagram inside the cover that I had not even noticed!
After closing up the spa pack and pump motor I turned the power back on and there was chatter. All I had to do was hit the temp switch and it stopped. Then I went out to check the temp this morning and decided 90 was set too low. When I turned on the pump to raise the temperature the contactor started to chatter again. Setting the temp higher didn’t help, so I turned the pump to high and back to low and it stopped chattering. There still seems to be a problem of some kind. I’ll talk to Joel again and see if we can figure it out.
Of course a couple of other minor problems still exist. I realized the indicator light for 220 has a broken wire–unfortunately I also broke the second wire so I just left that light off with the wires taped separately of course. And the indicator lights for the heater also are not coming on. Not sure if they are also broken or if there is a disconnected wire. One set of wires going to these lights is not connected to the board and even from the diagrams I cannot tell where they connect.
I also have to put the siding back on the side I removed! But tonight we babysit for the grandkids and we will be able to use the spa if it is not raining–only six months after I bought it. What a project.