Boiler triple Aquastat L8124 bad High limit switch or sensor.

Below are the problems I was having with my boiler after recently trying to convert it to be warm start after removing the domestic hot water coil. Replacing the Aquastat with a new one (L8124C-1003) fixed my issues.

Before replacing these were my issues:

I turned down the LO on the Aquastat down from 170 degrees to 130 after removing the domestic hot water coil but when I did so the boiler wasn't getting hot enough for the baseboard heat.

It appears that the high limit switch or temperature sensor was not working in the old triple Aquastat, if I set the LO to 130 degrees with a DIFF of 10 and High set at 190 when the thermostat is calling for heat the burner wont fire until the water temperature reaches approx. 130 degrees or so (Circulator pump stays on all the way down to 130 degrees).Also, the boiler will stop firing around 160 degrees under these same settings (wont get any hotter than 160 degrees under these settings). With the aforementioned settings it should fire around 180 degrees (190 - 10 degree non-adjustable HI DIFF).

These symptoms didn't show up until I turned the LO limit down (after removing domestic hot water coil) because before the boiler would always fire when it reached the LO limit of 170 and heat up to around 200 degrees.

I hope this helps someone, I couldn't find anything on the internet about someone having a similar problem with a triple aquastat.

DISCLAIMER: This video is for entertainment purposes only. Always hire a licensed professional.

Видео Boiler triple Aquastat L8124 bad High limit switch or sensor. канала iDoThings