trader_4於 2019年2月6日星期三 UTC-8下午4時35分35秒寫道：
On Wednesday, February 6, 2019 at 5:02:56 PM UTC-5, KMT wrote:
The 13 year old hydronic heating system in my house seemed to work fine until this winter. It used to warm up the house in 2~3 hours (say from 66 f to 70 f on not so cold days ). But I have noticed the temperature is not coming up fast enough this winter. The thermostat in the room is set at 61 f overnight and starts to call for heat at 7 AM for 68 f. So for the past few days at 7 AM, the thermostat reads 59 f and starts calling for heat. The boiler cycles on and off through out the day and at 12 PM, The thermostat reads around 60 f to 61 f. ONLY 1~2 degrees up for running 5 hours!!!! The system uses Honeywell Aquastat L4103D and L6006A. The dial points at 190 f on L4103D and its set at 140 f on L6006A with Diff 5 degrees. Is this the right setting? According to the gauge on the boiler, it is tuned on at 130 f and off at 190 f. It runs about minutes before shutting off and the next cycle comes on in about minutes. Is this right? Why is the house not warming up like it used to be?


Of course it's not right. I'd say it was not right from the beginning,
if it takes 2 to 3 hours to raise the temperature from 66 to 70. That is
unless it's 0F outside. I wouldn't put up with that. I have forced air,
I can do ~5 deg in an hour.

If the boiler is hot, next question would seem to be is the circulating pump
running? Is it filled with water? Is the thermostat constantly calling
for heat?

The pump should be running because it's hot and water in the pipes feel hot too. The thermostat is constantly calling for heat.