On Sunday, September 28, 2014 1:42:26 PM UTC-4, nestork wrote:


I've seen these boiler reset controls to sense outdoor temperature to

compensate for the water temperature flowing through hydronic

radiators.





No the reset control doesn't compensate for the water temperature in the

heating system; it lowers the set temperature of the heating system when

it's warm outside and raises it when it's cold outside.


I guess it depends on what he meant by compensating. An outdoor temp
reset systems does change the temp of the water flowing in the system
based on outdoor temp. I'd call that compensating.






Also, I'm not sure there's such a thing as a indoor/outdoor reset

control for STEAM heating systems because I'm not sure that steam

boilers are set up to produce varying temperature steam the way hydronic

boilers are set up to produce varying temperature water.

I wondered the same thing. I provided a link to a company that is
selling them. Exactly how they work, IDK. It apparently applies some
of the same principles to a steam system.




No. You're suggesting that he can program his timed thermostat to come

one earlier and shut off earlier to account for the thermal mass of the

walls. You could do that if it was just a few hours that the walls

remained warm or cool, but we're talking days. How can you program a 24

hour thermostat to come on and go off several days in advance?





It does not have to reach the 55 degree at night, that is a minimum. He



can set it to whatever works and makes sense. I'd think that 62 or 64

minimum would be better in many respects. Happy tenants and easier to

maintain the swings.



What I'm saying is that it makes no sense to have daily swings in

temperature when the thermal mass of the walls is an important factor in

the heating of the property for more than 24 hours. He'd be better off

to just set the reset temperature control at a comfortable level and

leave it that way 24/7 from October to March. That's the way most hot

water heating systems with indoor/outdoor reset controls are operated.


Just because there is more thermal mass doesn't mean that the same
principles don't still apply. If you setback the temp in building A
from 70F to 60F at night and it gets down to 60F at some point, before
having to rise again you save money. And if in building B you do the
same thing, but because of more thermal mass, it only gets down to 65F,
you still save money, just not as much.