Question about Honeywell L8148J aquastat

lekpeter

Do Honeywell L8148J aquastat have any differential built in?
I was in the basement for a while today and noticed my gas valve was doing short cycle duty. The high limit is set at 180 and the aquastat was going on and off in short cycles to try and hold 180. I thought there was some built-in differential.
Thanks in advance.

lekpeter

paul lessard_3

8DEG fixed nm

Unknown

Make sure it is not set on

Manual. There is a switch on the side for use with Powerpile systems that will run it on manual (in the event of power failure). If you have powerpile it should be set on auto. The differential on switches is 10 degrees.

If the limit is set for 180 it will go up to 180 and shut off, it will come back on at 170 degress. In very cold weather it is not unusual for systems to cycle on limit.

How many cycles per hour do you usually have with your system typical is 3 to 6 cycles per hour at 50% of heating load. When the temp drops outside it may come on and stay on longer.

Another thing to check is the setting on your thermostat anticipator. It should be set to match the amperage draw of the control which it direcly operates, i.e. zone valve, vent damper, relay .

If the thermostat has trouble getting satified such as set at 68 but the temp in house can only get to 65 then the system may be undersized (the boiler) or insufficient radiation.

lekpeter

Honeywell L8148J aquastat

Tim and Paul,

Thanks for the info.

I'm just south of Albany, NY and it was pretty cold out yesterday and the boiler (Hydrotherm) was satisfying the demand. I was watching the boiler temp gauge and it would hit 180, shut down, fire back up for 1.0 - 2 mins, shut down, and do this until the stat was satisfied. According to the boiler temp gauge there was no discernible differential.

tom mahon

why not

change limit setting to 220 so you do not cycle off of high limit..