Burnham Revolutions and ODR

KBP&H_3

Recently contacted Burnham about my Revolution boiler and they said not to use it w/ ODR,, even though they list and sell the EC 5000 control for it,The tech wouldn't give me anymore specifics. , anyone know what's up here?

CC.Rob

huh?

Gotta be a goof. The boiler is built for low temps.

S Daly_2

INTERNAL CIRCULATOR

When the Revolution boiler is off there is no flow through the boiler.  The internal circulator has to be running to provide flow.  With the boiler off you will not pick up the heat from the boiler with your boiler circulator.

KBP&H_3

Posts on the wall and wiring.

I'm familiar w/ wiring the internal circ control w/ the ODR control as I have done that, otherwise they short cycle like crazy, Their explanatiion is that the boiler needs to run against the 210 high limit.. Still couldn't get an answer as to why they sell the EC5000 for it.. if you can't use ODR..

CC.Rob

this must be a new thing?

And I sure don't understand why Burnham would say this.



As I understand the Revolution control system, the limit needs to be set to 210°F. This has to do with the transition temperature at which the VS3000 control begins to make the internal pump run fast versus slow, which is between 160°F and 170°F. The high limit has a built in differential of 30°F. If the high limit were set for 180°F, the temperature of the boiler would have to drop to 150°F before the burner came back on. At this temperature the internal pump will transition to a slow speed because of the cooler temperature. With a high limit of 210°F the burner will fire back up when the temperature drops to 180°F and that is above the transition point of the VS3000 board.



That said, it's certainly possible to wire up the Revolution as a 2-stage boiler, with stage1 as the internal circ and stage2 as the burner. That would allow a good purge of contained heat out to the system, even though there's only a couple gallons in the hx. Would be good to use a control that fires both stages on a DHW call.



What you're describing sounds a bit different though. Can you explain a bit more?



I agree that on straight ODR they chase the differential and cycle like crazy. At least with the tekmar ODR's, adding an indoor sensor provides more consistent firing cycles and better differential adjustment.