weil mclain

I have a weil mclain burner with three zones. I want to add a weil mclain (Ultra Plus 40) indirect fired water heater. I will combine two of the current three zones, freeing one up for the Ultra Plus 40. Currently my system runs year round as I am also using the tankless coil to preheat water that that feeds into my electric water tank. I will eliminate the tankless and electric tank when I install the Ultra Plus 40.
This is my question: How do I change the boiler to fire up only when a zone calls for heat, then let it cool to room temp when not in use? I understand it can also be wired so the circulator pump won't run until the boiler reaches temp.
(Boiler has ITT model ZPC-3 Zone Pump Controller and Triple Aquastat relay type L8124A, C )

 

If your boiler is an Ultra, just set it up in the MCBA and wire the circ directly from the boiler. Otherwise, go to B&G's web site, look up your zone controller and figure out how to put that zone on priority. Usually either the first or last zone on a controller can be set to have priority.

Even simpler, just take a good look inside your zone controller - it should be fairly obvious. If it isn't post links to pix here and the gurus here will tell you...

 

Don't combine the 2 zones into one. There are much easier ways to do this without going that route. If you can post some pic's, we will offer you suggestions as to how best to control it. Also, what is your boiler model #? Is it a Blue one, Gold one, or Ultra one. You can replace the triple with a cold start control, but the down side is that you may also need to replace the gaskets on the boiler, as they commonly leak when the boiler cools. To check this, turn your boiler off for 2-3 hours, then check to see if a puddle is forming under the boiler. Also, make sure you have your boiler tuned up annually, as that is a major factor in extending the life of your boiler. Do you have circulators for each zone, or zone valves? Why the W/M Ultra indirect? Just wondering. Boilers can be wired to do whatever you want, as long as you have the right controls.

 

HVAC EMT brings up a good point. Boilers that have been kept at minimum temps tend to leak when they cool down. The heat keeps the gaskets soft and pliable.
I also agree that it's better to add the extra zone and not combine. You're doing the work anyway, no sense loosing zone control.

If you're using hot water every day the savings in letting the unit cool down will be insignificant. Turn down the low limit to 120. This will also prevent condensation on the cast iron sections during humid weather, which is a large cause of early failure with cold-start boilers.

 

First of all thanks for all the replies.

My Boiler is Blue, Model #P368-WT 114,000 BTU/HR
Sorry, as far as I can tell this site won't allow me to post pictures, I do have it cleaned annually. I will check for gasket leaks by shuting down the boiler, it hasen't had any in the past. My reason for changing over to the W/M Ultra indirect is hopfully to save money in the long run, by eliminating the electric tank (aprox $130/yr) and by shuting down the boiler when not in use. The electric tank is 20 yrs old so I figure it will be due for replacement soon, the oil burner is aprox. 15 yrs old. If there are more economical solutions to providing hot water for a three person two bath home, I am open to suggestions. The cost of the W/M Ultra indirect tank is about $800 plus accesories of course.