T6

HotRod1975

after reading up on thermostats and having my old Emerson with mercury short cycling 7-10’cy is per hour that’s the Honeywell T6 is the way to go? Hopefully this will

Stop the on/off and over heating the home. Anyone have any advice using this specific model??? Or will I incur the same issues

thank you

HydronicMike

I think they are doing away with many of the T6 models.
Are you sure the short cycling is solely attributed to the thermostat?

HotRod1975

multiple.plumbers have come and said it's the thermostat. It's the boiler not skimmed. It's your vents so I'll try the thermostat first and see where we go

EdTheHeaterMan

The old mercury thermostats have a heat anticipator. there is usually an arrow that points in one direction on the heat anticipator. That arrow usually has a label that says LONGER. Have you tried adjusting the heat anticipator? What model Emerson do you have?

HotRod1975

i have it set to .8 and it runs great when starting a good 40-minute cold start then cuts off and 90 seconds later starts again runs for 5-7 clicks off 90-120 seconds and again repeat. House is boiling.

HotRod1975

my thought process is installing this and testing it with 1-3 cph and that is better than the 8 I'm.getting now

EdTheHeaterMan

If the thermostat is operating the boiler from a cold start for 40 minutes then starts the short cycling after that much time, you most likely have a pressure switch or LWCO that is cycling the burner, not the thermostat.  You can test this theory by disconnecting the thermostat and using a jumper wire at the thermostat location.  After the 40 minute run time, if the boiler will start to short cycle with the thermostat wires jumped together, then it is not the thermostat at fault.  Look elsewhere.

HotRod1975

https://forum.heatinghelp.com/discussion/comment/1873207#Comment_1873207

i have jumped it and it just runs and runs without stopping. The boiler I believe is a Dunkirk PSb-6D.

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1873211#Comment_1873211

Interesting…. So the thermostat is the part that is opening the burner circuit? seems strange after 40 minutes of operation…. There are some here that have added a time delay on break to the circuit to allow the extra 4 to 8 minutes of off time so the thermostat can cool off before the burners relight and stay lit for a few more minutes when they actually do relight. let me look up the Dunkirk PSb-6D to see where the best place to install that time delay. I'm not sure the thermostat replacement is going to help you in this case.

mattmia2

put an ammeter on the t-stat circuit and see how much current it is drawing after the 40 minutes shutdown. Something may have happened that is causing it to draw a ton of current when it shuts down on the aquastat or pressuretrol or whatever operating limit is reaching. Does it have a vent damper?

HotRod1975

thank you. I will also take a look and post each radiator and vent used per floor for the 4 floor home