Boiler temp vs high temp setting

JohnKV

I noticed my brand new Honeywell L8148A 1017 can be set for 190 degrees but boiler only reaches maybe 175. It was suggested the well wasn’t packed with grease (which is true) and may be causing the difference. My research suggests this grease will harden eventually so I’d rather avoid it. Question is, would it be safe to crank the high limit to say, 210 to make the boiler reach 190?

DZoro

Why so hot?
95% of the time 175* is more than enough water temp. for many designed systems. Are you having a issue with the system not reaching a constant set point.
Are you sure that the boiler thermometer is accurate?
D

JohnKV

Heats wonderfully. I I don’t believe the aquastat is accurate. My mercury thermometer on my upper boiler piping matches my tridicator on my boiler. Just falling 20 degrees short of my aquastat high temp setting when she shuts down

JohnKV

I’m assuming a longer burn cycle would be more efficient, if there’s still a call for heat, shouldn’t it hit the high temp limit then shutdown?

Jamie Hall

Does the boiler shut down at 175? Or is it that it just sits there running and doesn't go any higher? If it's the latter, are you sure that that simply isn't where it will go when the heat input at the boiler is equal to the heat output at the radiation?

JohnKV

Boiler shuts off at 175 like it hit its high limit, still a call for heat.

DZoro

Sounds like it heats great. With that being said, don't go any hotter. The hotter water temp the less efficient your boiler becomes. In this case to be more efficient, lower the temperature the better.
May want to put in the grease and see if there is a difference. But I really wouldn't bother.
D

JohnKV

It’s in the 30’s and 20’s here in Wisconsin at night lately, but it heats very well and barely runs it seems. If I set the high limit to 160, it runs for a few minutes every 10 or 15 minutes. I believe that’s called short cycling?

hot_rod

could be the temperature gauge is not accurate?
Without an accurate temperature reading at the control location it is hard to determine which is off

DZoro

Turning it up will make it worse. What size is the boiler and how large of a home do you have?
During this transitional season most standard boilers will be short cycling. When your design low temperature approaches anywhere from 0* to-16* will be where your boiler should run non stop, and maintain a constant set point. If it was sized perfectly, and nothing is perfect in this world
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JohnKV

I think it’s about 79,000 BTU, house is 1,655 square feet. 6 cast iron rads downstairs and one for the entire upstairs which is an almost 800 square foot master bedroom. It heats that whole upstairs surprisingly well with one rad. So far anyway, it’s not super cold yet either.