"Michael Gallagher" wrote in message
...
Hello,

I'm looking into getting a Weil-McLain Ultra Boiler installed this
Spring. I've done research on it, and came across a quote that
bothers me a little: Someone saw it at a home repair trade show and
said that it never shuts down, it modulates up and down. Now, does
that mean it never shuts down AT ALL, even when the temp gets to what
the thermostat is set at; or that it never shuts off while the heating
system is running, and goes off when the thermostat doesn't need
anymore heat? I've assumed the latter is true, but it wouldn't hurt
if someone who knows this system confirms that. Thanks.

Modulating is the way to go. Most boilers fire the burner at a pre-set
temperature, the water temp comes up and the burner shuts off until it drops
to another pre-set, the starts up again. Modulating boilers work by closing
down the gas and air to make a smaller flame once a certain temperature is
reached and opens up more as the temperature of the water drops. This is
more efficient and keeps a more even temperature.

Once the temperature gets to high in very mild weather, it will shut the
burner off

At works, we have three modulating boilers for high pressure steam that work
the same way. Works well and I'd not want it any other way.