Storage taking too long to charge. Any ideas???

I have been looking at this picture all day....... Your danfoss should be right at your boiler so the hot water can circulate around your boiler preheating your boiler water. Then the bypass loop slowly opens your danfoss valve to mix with hot water to stay above 140* If you let your boiler go cold you have 50' of cold water to heat up along with whats in your boiler.


On to your piping. It looks like it could go right past your storage and circulate thru your secondary and right back to your boiler causing it to go into idle while not hardly charging your tank.

I am unfamiliar with a injector??? does this take water from your primary and force it into the tank?

It also looks like your return from bottom of tank is tied into your primary?

My primary goes into the top of my tanks

I then pull off the top of tank with a pump to my hx and my flat plate for DHW

I then return to middle of tanks with dip tubes.

my returns to my boiler come off the bottom of the tanks

at my boiler I have the return water coming in thru a danfoss, thru a pump,then thru boiler back to tanks.

Rob

eriesigtau said:

The boiler sits in a leanto behind my garage. The pic I took is my storage and it in my basement. There are no circs at the boiler. The only thing between the boiler and the storage is my expansion tank. Why does the danfoss need to be right at the boiler? Basically, all there is between the boiler and the valve is 50ft of pipe. My pump does push into the danfoss and not away.

Click to expand...

I have to agree with the other folks here, your danfoss should be mounted at the return right next to your boiler. The idea is that you dont want the cold water to get into the boiler, since that will cause flue gas condensation, and can rot things out right quick. Also, if you have that 50' of piping, you will have a LOT longer time to warm up all of that water.

I thought this sounded vaguely familiar, and took a look at your prior posts. What you wrote in the middle of January make it sound like you got things squared away. So, were there subsequent problems last Winter that you didn't comment on? Or (if it was good last Winter), did you change anything else in addition to closing that valve?
https://www.hearth.com/econtent/index.php/forums/viewthread/57934/#785725
https://www.hearth.com/econtent/index.php/forums/viewthread/67644/#785786

eriesigtau said:

I have a Ecnoburn and 500gal of pressurized storage. If the house is calling for heat, the tank does not charge and vise versa. I have a danfoss valve that prevents cold water to return to the boiler. The problem I have is that the house can be satisfied with heat (thus storage is charging) but it takes forever for the storage to charge because the danfoss restricts flow back to the boiler until the tank water reaches 140. The boiler will actually sit idle because of this thus reducing efficientcy. What am I doing wrong here?

Click to expand...

The big picture is this: all your heat is getting sucked up by the house, or by the storage. In theory, you should satisfy the house first, then charge the storage. If this isnt happening then you are not driving your boiler hard enough, or its too small.

I looked at the diagram, other than being a pretty picture, its obviously disfunctional as a piping system, based on the omissions, and the in service changes to the designed operation as you have described.

As for the manifold bypass, I would leave that off. You want all the return water to mix with the energy source water coming in on the left.

Back to the big picture, we are talking heat transfer here. BTU= 500 delta T x GPM. So, for a given or fixed flow rate, heat transfer is proportional to the temperature difference between the supply and return.
On the boiler side, the danfoss should limit boiler return temp on the low side. So if thats 160 the supply should be like 180-200. Then there is the boiler supply to the manifold. A really high delta t indicates low flow. Low delta t indicates low load. The radiant probably works at the low end. The DHW heat exchanger can really suck heat like crazy, and drop the return temp like a stone. Your domestic water is like 45-50.

You didnt show how the danfoss was piped. It is possible to pipe wrong, but if that were the case your boiler temp would be out of the ballpark.
Start looking at operating temperature differences and report back.

Good luck

From you diagram it appears as though the danfoss and circ pump are not located at the boiler (which is where they are supposed to be).

The ball valve going from your boiler supply (hot) to the bypass side of your Danfoss (top of Danfoss) should be opened approximately 20-25% so as to force more of the hot water from the boiler into your tank.

You did not mention the size of your boiler or the sq. footage/heat loss of your house (both of which are important in trying to troubleshoot your problem).

FYI - My Effecta Lambda 35kw boiler with 1,000 gallons of storage will heat my 3,000 sq. ft house and charge my 1,000 gallons from 140F to 185F in one 5 hour burn when the outside temp is in the 30's.

I would recommend changing the location of your Danfoss valve to the read of the boiler itself.

Brian

I took another look at your photo and it appears as though there is a temperature gage on one end of the Danfoss valve (with no pipe connected to it).

If this is true than this is your problem.

The Danfoss valve needs to be installed so that the hot supply water leaving the top of the boiler will go though the by-pass portion on the top of the Danfoss as long as the water coming back from your tank is less than 140/160F. When the temp in this supply water gets to 140F, the thermostat in the Danfoss will open and let some hot water go into the top of the tank, down through the tank and back to the bottom of the boiler via. the Danfoss valve. As this temp gets greater, the thermostat will let more of the hot water go to the tank until the point where the water returing from the tank is 160F at which point the Danfoss is open wide and all hot water in going through the tank.

Brian

I recall a few years back there was a rash of Danfoss valves that came out with the label installed in the wrong orientation. When you replumb your bypass loop (which it sounds like you definitely need to do) make sure the internal components of the Danfoss match up with the label. It will never work right if the system input is actually plumbed to bypass and vice versa...

What is the temperature of your boiler when it's at "idle/low" speed while the storage is still charging?

Maybe I misunderstood - did you say the outlet valve on your storage tank was closed? That would certainly stop your tank from charging.