Buderus R2107 question.

ScottMP

The boiler will reset its operating temperature basedb upon the outside air. It will shut down the circulators if the boiler drops below ( I belive) 115°.

Scott

<A HREF="http://www.heatinghelp.com/getListed.cfm?id=237&Step=30">To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"</A>

Ted_9

From what Ive read in the application manual, is the following true.
Piping the heat zones as normal supply return, as per Application Drawing ECO-004.
Using this control with the outdoor reset and indoor t-stats, the right temp water will be supplied depending on the out door temp.

My question is do I have to pipe it with mixing valves?

Mark Eatherton1

Pump Logic

is adjustable and depends on the model used and can be set as low as 105 deg F. if memory serves me correctly.

ME

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

dconnors

Actually

Factory setpoint for pump logic is 104. Boiler does reset based on outside air and reference temp setpoint. There is detail on how to set the heating curve in the service manual. or call 1-800-buderus

Joe@buderus

Is this a radiant system? If it is, what is the design temperature? The R2107 will follow a low temperature heating curve but keep in mind the R2107 has a minumum burner firing temperature (approximately 125 degrees) on every burner cycle. The pump logic is factory set to 104 degrees. Pump logic will shut down the heat circuit (circulators tied into terminal 63 on the R2107) if the burner is firing and the boiler cannot maintain the pump logic setting.

Please keep a couple things in mind if not using a mixing valve. If there is a call for domestic the R2107 can increase temperature up to 180 degrees and when DHW is satisfied that temperature could possibly go into the radiant. The use of a boiler aquastat to control temperature in a radiant system is not the most accurate way for radiant loops. Depending on design temperature,I would consider at least a manual mixing valve for the radiant system to protect the radiant system, floor covering, etc...

ScottMP

Joe

I agree that some type of mixing valve should be used here if its radiant, but as a point of reference won't the 2107 shut down the boiler the closer it gets to the tank set point to help eliminate a surge of high temp ?

Scott

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Joe@buderus

2107 shut down

Yes, the R2107 will modulate the boiler temperature, but on a long demand from a draw down the R2107 will look to bring the boiler to max temperature to satisfy the demand. When the demand in the tank stops the R2107 then looks to use the heat and energized the heat circuit. Without a mix valve of some type, there is no high limit control in the radiant system.

Ted_9

Its ok, its all high temp copper fin. For future radiant we will install thew Buderus mix station.

Thanks for the help on the phone today Joe.

Mellow_2

I have a question

The 2107 shuts the burner down before the dhw tank is finished heating, right? This should cool the boiler down because the control learned how big the dhw tank is from previous cycles......This is what the reps are telling me ......sooooo In large radiant systems the heat in the boiler should not add much heat and could..................................................not be a problem (we can take our chances). I do not know for sure....... How about a small house with baseboard heat.....one zone split loop. I would like to do a 2107 with constant circ and room sensor. I think it will work well but wonder how much adjustment will be needed. The reps have told me it is not the best idea for bb heat. They said that because of bb not having enough MASS it works poorly on constant circ. They have said that bb will not convect at low temps, below 135 deg or the output of the bb drops so much that in the 50 to 60 degree outside range it will not have the output it needs. Anyone have good settings for this kind of setup. any help is appreciated.

Ted_9

You could install enough baseboard to get the right amount of btus. But 135 is on the low side and you would need quite a bit of b.b.

dconnors

Ted is right

You need alot more baseboard when you run constant circ. check your output and adjust accordingly. also you may want to tweak the curve a little