Diverting water to storage

[chuck172]

There are a few different piping configurations to divert some of the hot boiler supply water to storage while feeding the heating zones. When a small zone calls for heat, this can be important so as not to idle the boiler.
When using the Simplest Pressurized Storage System Design, I'm thinking of replacing the load circulator with the new Taco Delta T variable speed pump.
The pump speed will throttle with the delta T, when the pump slows, more hot water to storage. When the pump speeds up as in more of a heating demand less hot water to storage and more to the zone. This should all happen automatically, as there would be no restriction to the pressurized storage tank.
This would really simplify my system as I'm using two zone valves, a normally open and a normally closed with a ranco aquastat to accomplish this now.
I spoke to a tech @ Bio-heat and he thinks this would work rather well.
Any opinions?

 

[Nofossil]

There are a few different piping configurations to divert some of the hot boiler supply water to storage while feeding the heating zones. When a small zone calls for heat, this can be important so as not to idle the boiler.
When using the Simplest Pressurized Storage System Design, I'm thinking of replacing the load circulator with the new Taco Delta T variable speed pump.
The pump speed will throttle with the delta T, when the pump slows, more hot water to storage. When the pump speeds up as in more of a heating demand less hot water to storage and more to the zone. This should all happen automatically, as there would be no restriction to the pressurized storage tank.
This would really simplify my system as I'm using two zone valves, a normally open and a normally closed with a ranco aquastat to accomplish this now.
I spoke to a tech @ Bio-heat and he thinks this would work rather well.
Any opinions?

IMHO that's a great idea. An appropriate circulator coupled with zone valve will mimic that to some extent, as the number of open zone valves will determine the head loss through the heating loads and thereby put the load circ at a different point on its operating curve. However, a VS circ would be a far more sophisticated and tunable solution.

 

[chuck172]

Bio-heats drawing shows a Termovar diverting valve used to shunt the flow to the load circulator resulting in more flow to storage. It complicates the piping and the valve itself is expensive. With the VS pump, the piping is simple and automatic.
I think!

 

[in hot water]

consider an external control. This control allows you to use any circ, has more features, like digital readout, etc. Plus if the pump ever fails just replace with an inexpensive off the shelf pump.

Price it both way, but this tekmar is a sweet control.

I've used the Grundfos Miximizer for that exact use also.

hr

 

[chuck172]

I sure would like to expand on this diverting to storage idea a bit. Is there a cheaper home-brew for the delta-T circs.? What about delta P in this case?
If when two pumps are used in series, say the heating load pump is pumping at less speed than the wood boiler circulator, will storage absolutely get some flow?

 

[Nofossil]

I sure would like to expand on this diverting to storage idea a bit. Is there a cheaper home-brew for the delta-T circs.? What about delta P in this case?
If when two pumps are used in series, say the heating load pump is pumping at less speed than the wood boiler circulator, will storage absolutely get some flow?

If you're talking about a system plumbed like the 'simplest pressurized storage' sticky, the answer to your second question is 'yes'.

Home-brew is difficult. You need some electronic intelligence to determine how fast you want the pump to run. It's doable, but you'd need better electronic design skills than I have.

In my case, I'm using an off-the-shelf variable speed driver board that gets a control signal from my home-brew controller.

My first approach was the nearly famous 'poor mans variable speed circulator' which added control relays to a Grundfos three speed circulator so that the control system could select the most appropriate speed.