My task for this morning was to replace the coolant pump in my chiller with a more capable pump and restore coolant flow to my heat exchanger. I’m sorry to say I’ve failed to achieve my objective.
The day started well with just removing all my kegs and stripping out the cabinetry and insulation to give me access to the chiller internals.
The pump in question is the thing that looks like a white wheel near the centre in the picture above. Here’s a close-up and another picture with the pump lifted out of the water bath.
The propeller is the stirrer in the water bath and helps maintain an even temperature through the bath. Above it is the centrifugal water pump with a hose attached that comes out of the front of the chiller as a 3/8 stainless tube. This is the recirculation port used to chill the barrel on a hand pump or freeze the beer font to give that cold condensation/ice display. This pump runs continuously while the chiller is switched on.
In this picture I’ve replaced the pump with a 1500 litres/hour submersible pump.
Switch on, and…
…nothing! You might not see very clearly in the photo but there is no coolant flowing through this pipe into the heat exchanger. In fact there is just the merest dribble. So what’s gone wrong?
Well I had a similar problem not long back when one of the motorised valves failed so I wondered if it might be possible that another has failed. I decoupled the motor from the valve and could see the motor turn to the open and closed position as demanded by the control panel.
So could there be a blockage in the pipework? I disconnected the pipework at the feed to the heat exchanger added a length of 3/8 pipe as shown below and blew into it.
A few seconds later I saw and heard bubbles in the chiller water bath. No blockage.
So it appears I ordered a pump that has the same inadequate lift as the chiller pump. Idiot!
I’ve just ordered a 3000 litre/hour pump with a 2.8m lift and should receive it today sometime. I’m hoping this will be good enough but there seems to be a gap in the water pump market between smaller lower power pumps and more capable pumps so if this doesn’t work it will take a bit of searching to find something suitable. Let’s hope this one does the job.