Constant Circulation

Paul_28

Does it work with fin base board? Is the circulator pump ever off? Is there a faster response from the night temperature to the day temperature?

jim lockard

circulation

Yes--In the off season, you can install an outside sensor set at say 65 degrees to turn on the pump ----Yes. Best Wishes J.Lockard

Paul_28

Confused

Why would I want to do that?

Ted_9

I think what he is saying is that you can do outdoor reset with constant circulation . You can set the outdoor temp so that the heating will start at say anything lower than 68 for heating and it will then shut down the heating in the spring when it gets above 68.

And yes it works great with copper fin tube tube, but everything must be engineered by a hydronics professional.

PATRIOT HEATING & COOLING, INC.

jim lockard

Thanks

Paul that what I was trying to say. What Ted said.

Constantin

Sure it works... but what's the benefit?

Constant circulation keeps thermal expansion to a very low level. It does this by basically running water continuously through the baseboard at much lower temperatures than baseboard usually is designed for.

IIRC, baseboard is usually sized to be run at 180°F on a design day (i.e. when it's about as cold as it gets). The other times during the year, it gets hit with slugs of water at 140°F+ as the thermostats call "on-off" for heat. Constant circulation allows much better (even) heat control when installed in conjunction with outdoor reset and a good control system.

Instead of shocking the fin-board with "on-off" slugs of hot water, a constant circulation system will basically modulate the water temperature to match the heat loss of the house. Ideally, such systems are matched with a modulating boiler that can add just enough BTU's to keep you and the house happy. However, you can also resort to a 4-way valve with a high-mass boiler to keep the boiler happy.

Thus, constant circulation is great for systems that either contain a boiler that can accept low return water temps or which has been piped to protect the boiler from condensation. Constant circulation systems work best when the baseboard has been sized to work at 140°F on a design day. However, if your boiler cannot handle low return temperatures or your system isn't piped to protect it, then don't attempt it.

So, it can work for baseboard and no, the pump is never off during the heating season (that's the whole point of constant circulation). While having a pump on all the time might seem like a waste of energy, consider that most pumps consume something on the order of 20-50 dollars over the entire heating season. Plus, nearly all of their energy ends up as heat in the water.

As for night-time vs. daytime temperature response (I think you're referring to setback), you may find a constant circulation system a bit more responsive as its mean water temperature is probably higher than the one in a conventional system. However, responsiveness is probably driven primarily by the size of the boiler, the distribution system, and the emitters in the rooms.

Paul_28

I have

I have that feature on the Buderus 2107 controller.

Ted_9

If you use the constant circ on the 2107, and you want to set back at night with a BFU indoor sensor or the programming you can. You can also adjust the temperature differance from day to night. I think the default is 7 degrees, but you can change it.

Why dont you tell us more about your system?

PATRIOT HEATING & COOLING, INC.

Constantin

You may have the feature...

...but before you enable it, be sure that the piping for the boiler will allow it to operatew safely (i.e. w/o condensation). Go over the install diagrams that came with the boiler to see how Buderus implements CC and boiler protection. If you have their latest boiler (the condensing gas, wall-hung unit) then CC is for you...

Ted_9

I agree with Constantin. The setings and programing should be done by you installer. If the installer is not known or present, please call Buderus or a pro.

www.buderus.net




PATRIOT HEATING & COOLING, INC.

Paul_28

Thank you

Thank you all for your replys...