HinewaisMan
Well-Known Member
G'day,
A little assistance would be greatly appreciated please.
I have an Isotherm ASU 4701 fridge unit - water cooled and after many years sterling service, the water pump has died, electrically dead, not turning.
It's an old 3 pot Shurflo diaphram pump - no markings easily visible on it to say what pump - but the spec sheet says flow rates between 3-5ltr/min. The pump itself lives encased in the coils of the heat exchanger, basically a pipe within which there is another coolant pipe. The water pump sends the water down the large diam pipe and removes the heat from the coolant pipe.
And these heat exchange pipes are pretty tightly coiled around the body of the bust pump and don't want to come off. I'm loath to try too hard, too many thin coolant pipes to risk folding.
Fair enough I thought, it's easy to just fit, wire and plumb a remote pump, keep the old pump body in place and not risk damaging the heat exchanger.
BUT!
The power supply to the pump goes through a "Voltage Reducer" which knocks the voltage down to 5V - the book of words says this is to "achieve near silent operation", "reducing the speed of the pump and so the amount of water flowing through it".
So, my questions are......
1. Can I get away with picking up a suitable 12V replacement pump and running it at 5V - or will I kill it? (It's a question my wallet is very interested in - the picked-up pump say £100, Isotherm replacement £300!)
2. If I need a flow rate of say 5lts/min at 5V, what size pump should I get? Is it a linear relationship with a DC motor between voltages and speed? ie if I get a pump rated at 12lts/min at 12V, will that give me 5lts/min at 5V?
Many thanks
Peter
A little assistance would be greatly appreciated please.
I have an Isotherm ASU 4701 fridge unit - water cooled and after many years sterling service, the water pump has died, electrically dead, not turning.
It's an old 3 pot Shurflo diaphram pump - no markings easily visible on it to say what pump - but the spec sheet says flow rates between 3-5ltr/min. The pump itself lives encased in the coils of the heat exchanger, basically a pipe within which there is another coolant pipe. The water pump sends the water down the large diam pipe and removes the heat from the coolant pipe.
And these heat exchange pipes are pretty tightly coiled around the body of the bust pump and don't want to come off. I'm loath to try too hard, too many thin coolant pipes to risk folding.
Fair enough I thought, it's easy to just fit, wire and plumb a remote pump, keep the old pump body in place and not risk damaging the heat exchanger.
BUT!
The power supply to the pump goes through a "Voltage Reducer" which knocks the voltage down to 5V - the book of words says this is to "achieve near silent operation", "reducing the speed of the pump and so the amount of water flowing through it".
So, my questions are......
1. Can I get away with picking up a suitable 12V replacement pump and running it at 5V - or will I kill it? (It's a question my wallet is very interested in - the picked-up pump say £100, Isotherm replacement £300!)
2. If I need a flow rate of say 5lts/min at 5V, what size pump should I get? Is it a linear relationship with a DC motor between voltages and speed? ie if I get a pump rated at 12lts/min at 12V, will that give me 5lts/min at 5V?
Many thanks
Peter
