Recent content by 120d

Update: Well, that's frustrating! I was looking at how hard it would be to free the manifold to replace bypass valve when I noticed the heater appeared to be plumbed backwards. Outlet plumbing connected to clearly market "inlet" on manifold. The fairly large, somewhat respected local pool...

Thanks... Looks like I'll try the bypass valve replacement. Interesting I noticed the heater immediately heats water +14 degrees when it kicks on. That explains why it cycles at 90 (it reads 104). I suppose water getting trapped or slow flow could cause that? Thermistor was replaced and same 14...

Hi, I have a 6 year old master temp 400 heating a pool/spa combo. It has been working fine until recently. Now it heats the spa from 60 to 90 degrees fine... But then consistently starts to cycle above 90 degrees where the display shows the temp climb rapidly (15-30 seconds) from 90 to the 104...