steam boiler replacement

hvacdmia2

Putting in a new Weil-McLain LGB-7 steam boiler. Very large house with 10 pneumatic thermostats and 20 pneumatic valves. The boiler comes set up so that a control can be added too run it in either low or high fire. Thought about using a pressure control so that if less than 1lb steam high would run, once it gets over 1lb. Low would run, or I could use a existing outdoor bulb and below a certain temp. high would run.
I’m leaning more towards the pressure control thing that on cool mornings the boiler would run on high at first getting steam up quicker and the zone valves probably won’t all be open at the same time, except for the initial warm up and on really cold days.
Has anyone ever done this? Will it save on the heating bill? Should I just leave it run on high all the time?
Also I have a F&T end of main trap that connects to my return only a couple of feet from my combination open water reservoir tank condensate feed pump, should I put some extra piping on the outlet to let the condensate cool a little before it gets to the tank.

Robert O'Connor_7

WM??

On the LGB I belive you get two (2) pressuretrols with it, but depending on where you live (codes) you may be required to install one with a manual reset (need to buy!), then just use the second limit(or now, the extra one) as the high fire control and wire it directly to the burners high/low fire wiring. It should then start on low, then go to high, then (depending on your cut out setting) go back to low to maintain operating pressure. Is this oil or gas?..Robert O'Connor/NJ

hvacdmia2

LGB pressure controls

The LGB does come with 2 controls and all the wiring,110v, to hook them up. I think WM wants one to be the primary control and the second one to be a back up. Not too difficult to add one more and hook in the 24v high fire circuit. I did get the boiler fired up today and have to go back next week to finish up.

Robert O'Connor_7

Limit...

Check your state or local codes regarding the need for a manual reset. A manual reset is typically required in most states. It's basically a high limit pressuretrol that when it reaches its set point, it shuts the burner down and must be "manually reset" hence the name. If so, then just use the spare as your high fire controller. Does the burner have a low fire only switch?..Robert O'Connor/NJ

hvacdmia2

I will have to check if code requires a manual reset limit. The boiler comes set up to start on low fire, when low fire is proved it goes to high fire. Control supplement shows optional high fire control can be used. Natural gas boiler, 780,000 btu

Boiler Guy

Hi/Low

I use that option on virtually ever job I can. I usually install a delay timer to hold the unit in low fire for up to 15 minutes and an outdoor temperature sensor to use low fire exclusively until at least -5F.. Works Great