Troubleshooting heat exchanger- water not heating up while pumping wort through

[emergent7]

Hi all,

I brewed a Scotch Ale a couple days ago- everything went great until it came time to cool down the wort. The valve for the cold water is directly above the HE and goes straight to the HLT. Glycol was running through it at about 33F, yet even when the wort was just trickling through the HE I could only get the temp down to about 100F.

Any ideas about what could be going wrong? I did about everything I could think of- shut the glycol off on my fermenters, add more glycol to the chiller, etc. The only hint I found was that the temp of the water in the HLT wasn't increasing much at all (to about 70F). I called the previous brewer on this system and he was clueless what could be wrong. I ended up pumping the wort semi-hot into the fermenter and chilling the rest down with the glycol jacket. Any help would be appreciated!

[jimvgjr]

Were you putting a heavy load on the chiller? I assume yes since you commented that you shut the glycol off to your fermenters.


Think you could you have some blockage in the first section (wort side) that is not allowing flow through some, or all, of the water/wort plates? This would put all the load on the glycol chiller, and would explain why your exiting water is not warming up past 70 F.

Good Luck,

Jim

[BrewinLou]

Tell me more about your set up. Do you have a cold liquor tank and glycol to cold liquor heat exchanger? Then a cold liquor to hot wort heat exchanger?

[dick murton]

When did you last clean the heat exchanger properly, at correct flow rates (1.3 to 1.5 times product flow), preferably hot caustic, preferably in backward direction. Suggest it might be time to pull it apart and manually clean. The flow should not be a trickle as this will not allow good heat transfer

The water flow required is typically 1 to 1.2 litres cold water per litre of hot wort. The heat excahnger has to be sized for the wort flow to ensure turbulent flow in both the wort side and the cold water / glycol sides. Without sufficient details it sounds as though your flow rates are way too low for the heat excahnger and it is channelling, or is hugely undersized. Sorry but i have never worked out a unit area / flow rate, though this should actually be fairly easy to do. We simply contact the supply stating flow rate, and what the temperatures have to be and leave them to scope it

Of course it could be even more drastic than that, that the H ex has not been put together so the wort and coolant are alternating correctly.