Question about Honeywell T87k thermostat

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Adm

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Greetings,

I just replaced an old H-well round mercury thermostat with a new T87k heat only because the old one's room temp indicator was stuck on 72. I installed the new according to the the directions and set the dip switch to 2 on and left 1 off as indicated in the instructions, but now my heat short cycles.

I have an oil fired hydronic monoflow with cast iron baseboards if that helps... the instructions say dip switch 2 on for "water" heat, is there a different setting to lengthen the heating cycle, or should I just re-install the old one?

TIA for any advice...
 

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What is your short cycle time? Set the thermostat to 80 or so and time it. The setting OFF-ON is 3 Cycles per hour, OFF-OFF is 5 cycle per hour. IS there an outside temperature sensor?


Every thermostat has a cycle rate. The purpose of cycle rate is to keep a room's temperature even — never noticeably hot or cold, even though sometimes the equipment is on and sometimes off. Electronic thermostats have a cycle rate adjustment built into them. That's easier, but less fun, than setting the anticipator.

Google "why do thermostat have cycles per hour". Plenty of comments
 
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