Superstor issues...

Hvacman

I'm on a commercial job with 2 80 gallon Superstors. The complaint is poor delivery at peak times but I've not seen them reach setpoint (150)even in the middle of the day. The building has a Leonard mixing valve to bring the supply temp to the apartments to +/- 120 deg. The tank circulators pull supply water from the boiler supply header and at my pumps the water temp is 170, indicated temp of the header is 190 (8 feet upstream), by the time the supply reaches the tanks it has dropped to 130-140. (10 feet downstream from the pumps) This symptom tells me I have flow issues so I opened circut setters up a bit with no change. Delta T across the boiler side of tanks is only 10 deg. Thinking maybe limed up tank I pulled water off the bottom of the DHW side of the tank expecting to have lime and scale in the bottom of the tank but the water was sparkly clean and only lukewarm. Can the coil lime up and restrict flow? Low delta suggests too much flow... Ideas?

GW

i can't follow your explanation

what kind of pumps you running?

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

JohnNY

Perhaps more importantly...

...how many BTUs are you burning?

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dave Stroman

The fact that you are dropping that much in temp in just 10 ft does not sound like a low flow condition, it sounds like a no flow condition.

Dave Stroman

bob_46

If

you have 190º water in the header WHY is it only 130º to 140º entering the heat-x? Where is the heat going?

Bill_102

Superstor

Did the system ever work properly? Any evidence of lime at fixture outlets. Interior of coil unlikely to be plugged or damaged. Super Stor uses a pancake Coil that can be shaken clean if tank is drained and boiler water is then circ thru the coil with an empty tank. The coil will expand up to 10". Add cold water to the tank and you will hear the coil contract with a bang. Any deposites will be removed.

Dave Stroman

That is pretty cool, Bill. I did not know that about the SS. I have avoided using them for the very reason that the coils could not be cleaned.

But I do not think that is the problem here. If the coils were clogged, there would be little or no temp drop through the coil. If there were any flow at all through the coil, there would not be such a temp drop before the water even got to the tank. There is some missing or incorrect info here. It is just not adding up. If the tank are getting hot at all, it means that there is some flow through the coils. If the boiler is 190, then the temp going to the coils has to be 190 also. Are the pumps installed backwards?

Dave Stroman

Hvacman

More info...

Whoa, thanks for the replies! I took my temps with an infared, the 120 deg. reading at the tank inlet is close, I could hold onto the pipe with discomfort after a few seconds. The pumps are piped correctly, are turning the right direction and the couplings are good... I did not look at the impellers. The job is 9 years old, the super describes a gradual loss of supply temps.

Is the method described for cleaning the coil endorsed by Superstor?

I have the super checking his water bills too... seems there is alot of cold water flow into the tanks during times where usage should be low. As I said before, the tanks never reach setpoint of 150 even at night.