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Posted By Woodfarmer1,
Nov 17, 2017 at 8:31 AM
i currently run a taco 007, should I switch to a larger pump or a grundfos alpha for better mixing?
Is this to mix design temp or just turn over the tank water
I'm not sure what to call it, I draw off the top of the tank and the return is at the bottom
Okay so the garn supply and return are on one end, what’s the other end connect to, do you have a flat plate behind the garn? Need some piping descriptions
Yes it's a 40 plate I believe
I think it's all 1" pipe with a wilo circ pump the same size as the taco on the inside of the house
Is there something about the way it's working now that doesn't seem right or seems like could be better?
So the flat plate is in the basement with the wilo out in the garn barn, with a 1 inch pex loop?, how many feet round trip, is the wilo wired to run all the time or only on a call? And as maple asks, is there a problem
TC, the other way round,3/4 thermo buried down 5' about 70' to basement with the wilo on 24/7
It's 1 1/2" black pipe off the boiler to 1" copper to HX plumbed according to the Garn manual
We spoke last spring about the heat exchanger, I cleaned it all out and that wasn't the issue
I'm only trying to solve the difference in temps at the boiler for the moment
There is a 20 degree diff in temp between the temperature in the Garn tank and the supply side at the HX
Your underground piping is only 3/4"? Is the HX next to the Garn or in the house?
What is the dT between where the water leaves the Garn, and enters the HX? Unclear from posts if it's that, or the 20dT is between a temp reading somewhere on the Garn tank & where it leaves it.
Underground looks like 1” not 3/4”
HX is next to the Garn
The 20dT is between the water temperature in the Garn and at the HX water supply sensor according to the control box on the Garn.
Can you verify the garn sensor with another temp reader, is the sensor covered with insulation, I vaguely remember garn having a issue with the sensors or placement of them to get accurate readings.
Do you have a vacuum gauge on the inlet side of the circulator and pressure gauge on the outlet side of the circulator?????
Why is it you do not have flooded suction with the circulator pulling the hot water off the bottom the tank?
The circulator will not have work as hard and create a larger vacuum(pressure gradient) when moving the water by drawing water off the bottom of the storage tank.
The total weight of the water in the Garn boiler will create the mechanical advantage of flooded suction for your circulator.
Garn recommends the supply come off the top of the tank( actually about 1ft ) below the surface and the circ basically on the floor. Unless he is overfiring npsh shouldn’t be a factor
I would love to see the HG water column measurement on that set up.
No gauges, we follwed the Garn manual on install.
I just taped the Garn sensors on the supply before the HX and on the return side, after a burn I’ll read them.
The draw off the top of the tank looks like 1 1/2” pipe and the return is 1” pipe lays almost on the bottom of the boiler and terminates 1’ from the front of the boiler, so it’s probably 6’ in length, I can’t see there being much mixing in their design.
Where would the hottest water be in the boiler?
What I am trying to determine is will a larger pump move more water and increase my supply temp?
I don't have Garn experience - but if it is pulling off the top of the boiler now, how would increasing flow make the supply water hotter? Shouldn't that be the hottest place to pull from?
I might be missing something here...
So is this the problem you are trying to resolve?
Sent from my SM-G950U using Tapatalk
If I understand this correctly you are trying to mix the stratified hot water water layer in the top of the Garn reservoir? that reduces the total temperature of the water in the mass and unless you have insulated it well a lose lose.
Short of firing more often I do not see you solving this as you need to keep the water hotter anyway.
Is the water steaming at least a little when you look at the water when you open the access hatch
and point a flashlight down at the water?
You need isolation valves for your circulator with gauge ports for both pressure and vacuum as well as a good temperature gauge tee'd in the line like those sold by Marsh Instruments.
Sounds like this might need Garn specific feedback. The only way I can see more flow helping anything, is if the Garn doesn't draw its supply water from where the water would be the hottest. (Presumably at the top?). Is that the case?
Also sounds like accurate verified (redundantly measured) temp measurements might help, at points where water is leaving/entering components. And maybe also where this temp guage is reading too.
So I spoke to Garn about stratification, they recommended a Taco 0015e to get better mixing and more flow.
$200 later and there is no difference.
It seems like we’re going around in circles here, can you answer questions,
You have a new style garn controller, with the tank temp in one of the two 3/4 inch ports above the loading door?
Your supply sensor is on the piping between the garn and the inlet to the flat plate, or the b side of the hx that would supply the house?
Questions have been posted but not answered.
Are Garns different from other boilers? The supply doesn't come off the top where water would be hottest? Shouldn't it - to make full use of storage capacity?
Well Maple I’ve been a little busy cutting wood in this tropical weather.
The hot water sensor is in the smaller hole on top the boiler that also holds the float sensor, so it’s only about 6-8” from the top of the water.
Supply sensor is on the inlet to the flat plate HX.
There is 4’ of 1 1/2 black pipe coming off the back of the Garn 12” from the top, so only down in 8” of water.
The it flows through 1”copper through the HX it’s 3” thick so about 40 plate?
Then into the 1” black pipe that shoots return water 3” off the bottom of the boiler ending about a foot from the front of the boiler.