Revolution boiler, buffer tank, and micro zones.

Tristan

To  Zman, Gordan and other who help me on my previous post about short cycling of Revolutin boiler. Is a buffer tank (e.g. Boiler Buddy) the only solution to my problem? Instaead of paying high$ for a buffer tank, Can I use a cheap electric water heater and use it as buffer tank? What type?

Also, what about a two stage boiler control that would run the pump first and then fire the boiler?  Would that resolve short cycling too?

Let me know,

Tristan

Gordan

Yes, you can use a water heater

It's actually fairly common practice to do that with mod-cons where a buffer is still required to avoid short cycling during low demand periods (IOW, when the heat loss is significantly below the min modulation.) But those are typically low-temp systems. I'm not sure how well a cheapo electric hot water tank would hold up to higher water temperatures. I'm not saying it wouldn't, but I'd be inclined to observe the manufacturer's stated limits on operating temperature.



Then you could have the boiler recharge the buffer on a wide differential, and the outdoor reset mixing circuit would slowly trickle off some of that heat to the home. Yes, that would help greatly with cycling.

Pat_11

Ergomax

Check out Ergomax. Buffer tank with domestic hot water coils in the tank.

www.ergomax.com

Gordan

Definitely not cheap

About twice as much as a buffer tank of the same capacity, for what it's worth.

scott markle_2

Buffer considerations

Cycling is (in my opinion) often a control problem as opposed to insufficient load problem.

I don't know anything about the revolution, but mod cons generally see a high delta and respond with a high firing rate, when not required. A buffer can have the effect of "appearing" as load (high delta) and the boiler responds with higher firing rates.



I'v hade some good results setting very low maximum firing rates, on boilers that have this parameter.



Also I once purchased a boiler buddy more or less from the manufacture in Wisconsin or Milwaukee or where ever it's welded up, the small tank was a fairly reasonable ups rate.As the distribution expanded they wanted me to go through a regional distributor and the price went from ok, to Idk. To low volume to pass along at a competitive margin I guess.



I like Tekmar and mixing down stream of the buffer. The threads (1" I think) on hot water electric element tappings are not taper but I'v had good luck with loctite "floss" dope. Use unions so if you have a problem you can't try again without to much trauma

scott markle_2

Oops