Is a high tech variable pump worth it?

[RobC]

JP. I going to assume you have a mixing valve at the wood boiler. Between that valve and the boiler there should be a circulator. Return water gets pulled through the mixing valve and pushed into WB. The water needs to flow some place. If your zones are off it will be pushed out the top of the WB to top storage ( path of least resistance ) and pushed to the bottom of storage and cool water will return, gets pulled back to boiler.
So next, zone valve opens and circulator comes on. Now, some of the hot water going to storage gets diverted to zones, if there is any extra flow it will end up circulating thru storage but at a reduced rate. Zone closes and you continue charging storage.
Wood Boiler burns out. WB circulator shuts off and it has a check valve in it restricting flow. Zone calls for heat ( path of least resistance ? ) water will be pulled out the top of storage and returned to bottom of storage.
The extra valve on my diagram at the zones recirculates any water that is not below 150. It's kind-of the opposite of the tempering valve at back of boiler. However this won't keep the flow logic described above from working.
Rob

 

[ewdudley]

Sorry, you misunderstood my question.. or I've just been laying around this hotel for TOO LONG. I go home tomorrow.

The constant taco 00R pumps are staying. I was questioning a variable pump to supply THEM from the new 1000 gal of WB heated storage.

My idea is that the new, variable pump would supply hot water from storage to a point just before the spirovent on top of boiler.

Sorry, it's starting to sink in. Guess we need a schematic.

With valving it should be possible for the loads to pull directly from storage if storage is in parallel with the existing boiler

Does the existing boiler have a re-circ loop to mix with the radiant returns to maintain return temperature?

 

[JP11]

Sorry.. No schematic yet. Boiler is being purchased and schematic being produced as soon as I take some pics to send to Mark at AHONA.

The reason I thought two pumps...

Pump #1 (additional pump added to system that is) would be on return line to wood boiler. That would circulate water thru WB to storage. 1.5 inch lines, danfoss protection on return water and it goes out from boiler.. T'd to feed into top of two vertical 500 tanks. Return water from bottom T'd 500 tanks.

So in my mind that pump is controlled by WB and only runs when there's heat being generated by the WB.

Now.. DAYS yeah right maybe in summer, later.. The home needs heat. I think that when any zone needs heat... it would turn on a pump #2 added to current system that is T'd into the top of tank (opposite side.. tanks will have a bung at the top and bottom on the last of the flat surface before dome starts) This will match my boiler plumbing.. 1" Return from current setup would be back to 1" bung in tank setup.

Water from my WB would NOT travel to the current Oil boiler hot manifold before traveling to the tank setup.

I believe there is a return loop on my current setup. I will get better pics when I go home.. which is thankfully today. Sick of sitting in this hotel. Need to quit shopping for boiler stuff. Bought a X27 just to bust up stuff that's already in the garage. Also got a manometer, just to play with. Dang ebay.

JP

 

[woodsmaster]

I have a panel systym with TRVs It currently has a grundfos 15 -58 that I keep on low. Where the pex enters the radiaters there is a bypass so if the valve is closed the water will still circulate. I was thinking of removing the bypasses and installing a variable speed pump. I was thinking it would cut transmission losses in the crawl space and save electric. Would this be worth doing or should I leave well enough alone ?

Woodmaster, that Grundfos 15-58 draws 60Watts on the low setting. A little calculation say that if you run it constantly, it'll use about $4.30 per month of use. You'll wear it out faster, but a VDT pump is pretty expensive and the Grundfos is only about $85 new.

JD

I was thinking that it would also cut down on mixing in my storage. If the rads ain't calling for heat there wouldn't be water circulating. The way it is now the water always circulates.

 

[ALASKAPF185]

For speed, and accuracy a good diagram would be best. Heaterman had a great post per application. Boiler piping is everything to a systems efficiency. Don't forget the VDT series comes in different size pumps. 006-0012 or 14. I have seen 0012 VDT put where a 007 was already close and worked for years. So even at its lowest speed it was way too much for the system. Unfortunately the first thing the customer did was bad mouth the product on the net, and all the noise or errors it was doing was an improper sizing issue. Keep in mind when sizing correctly to keep within GPM and water speed parameters.