What is the best cleaner to de-scale a heat exchanger stack?

Be very, very careful with the stack. Try soaking in a gentle descaler first, such as Kilrock (available in B&Q etc). Do the tubes really need rodding?
 
Unless very severely scaled I would use a domestic descaler such as KillRock K or a central heating boiler descaler such as Fernox DS-3

Killrock K is based on formic acid. Fernox DS-3 is based on sulfamic acid
 
I did a Perkins 6354 stack with a straightened and sharpened wire coathanger, it worked very well. I had no access to the products above, but they sound like a good idea to soften the deposits before physical removal.
 
Gary Fox said:
I did a Perkins 6354 stack with a straightened and sharpened wire coathanger, it worked very well. I had no access to the products above, but they sound like a good idea to soften the deposits before physical removal.
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No need for physical removal after using Rydlyme Gary.
 
If you havent used Rydlyme before the objective is to run it through on a continous loop, so you need to think about how to do this. As it starts to remove the intitial deposits you will get a lot of frothing of the Rydlyme in the capture bucket, which will gradually subside as it does its job. It is colour coded to indicate when it is spent.

Of course the same idea as what happens in a kettle when you add de-scaler.
 
ip485 said:
If you havent used Rydlyme before the objective is to run it through on a continous loop, so you need to think about how to do this. As it starts to remove the intitial deposits you will get a lot of frothing of the Rydlyme in the capture bucket, which will gradually subside as it does its job. It is colour coded to indicate when it is spent.

Of course the same idea as what happens in a kettle when you add de-scaler.
Click to expand...

You surely don't run descaler in a continuous loop through a kettle?
 
Nah, keep that for the coffee percolator, the one that bubbles the liquid through the coffee and back around. :)
 
You should be able to look into the heat exchanger tubes and see if there is any blockage. Torch at one end, your eye at the other end. The spoke from a bicycle wheel is perfect for the task, just be gentle. You may actually not need to resort to acid.

I'd have a look first, then see how firm, being gentle, any closed tubes are - before resorting to acid

Jonathan
 
Most of the folks who have used one of the many proprietory descaling fluids, will have set up a recirculation system using a pump of some description.
Need to remove impellor to improve flow.
An old bilge pump should do the job. One chap recently left the set up running on his Volvo Penta 61 engine for 6 hours, reversing the flow every hour or so.
He still needed to remove the risers and physically remove some scale .
Have used a stainless steel rod to ensure tubes were clear on Perkins Sabre heat exchangers.
 
ip485 said:
If you havent used Rydlyme before the objective is to run it through on a continous loop, so you need to think about how to do this. As it starts to remove the intitial deposits you will get a lot of frothing of the Rydlyme in the capture bucket, which will gradually subside as it does its job. It is colour coded to indicate when it is spent.

Of course the same idea as what happens in a kettle when you add de-scaler.
Click to expand...
Take out the impeller and connect a bilge pump to a hose going Into the water pump.
Put it in a bucket of ridlyme.
Take the hose off the exhaust elbow. Connect that to a clear hose running back to the bucket.
Run until clear brown liquid is being returned. Many hours.
 
Neeves said:
You should be able to look into the heat exchanger tubes and see if there is any blockage. Torch at one end, your eye at the other end. The spoke from a bicycle wheel is perfect for the task, just be gentle. You may actually not need to resort to acid.

I'd have a look first, then see how firm, being gentle, any closed tubes are - before resorting to acid

Jonathan
Click to expand...

I think you have that backwards Jonathan. I'd flush the whole system with Rydlyme, before resorting to poking wires up the tube stack. Rydlyme will leave the whole system clean and descaled, rather than just part of it and no risk of damage.
 
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Elessar said:
Take out the impeller and connect a bilge pump to a hose going Into the water pump.
Put it in a bucket of ridlyme.
Take the hose off the exhaust elbow. Connect that to a clear hose running back to the bucket.
Run until clear brown liquid is being returned. Many hours.
Click to expand...

I have used a bilge pump in the past, but if you don't have a spare bilge pump a cheap pond pump also works well.
 
PaulRainbow said:
I think you have that backwards Jonathan. I'd flush the whole system with Rydlyme, before resorting to poking wires up the tube stack. Rydlyme will leave the whole system clean and descaled, rather than just part of it and no risk of damage.
Click to expand...

I would not use acid unless I thought I had a problem. Looking through the heat exchanger is quick, painless, requires nothing but eyesight. Your blockage might be a bit of weed - a bicycle spoke will tell you what it is.

Using acid is solving a problem that might not exist.

But each to their own.

Jonathan
 
Neeves said:
I would not use acid unless I thought I had a problem. Looking through the heat exchanger is quick, painless, requires nothing but eyesight. Your blockage might be a bit of weed - a bicycle spoke will tell you what it is.

Using acid is solving a problem that might not exist.

But each to their own.

Jonathan
Click to expand...

With respect, the OP and the whole thread is about descaling, if the tube stack needs descaling, so does the rest of the circuit.
 
Rosie1963 said:
The stack is a Bowman unit for a Perkins. I don't want to damage any parts.
Is there a specific tool to rod the tubes too?
Many thanks,
Click to expand...

I also have a bowman heat exchange and the tubes of the stack carry the sea water through to cool the recirculating fresh water.

You could use a descaling solution by removing the stack and soaking it in a bowl of the solution.

You could also rod the tubes with a Straw Cleaning Brush of thin bottle brush.

Buy Faithful to Nature Straw Cleaning Brush Online at Faithful to Nature

Explore long thin brushes for cleaning | Amazon.com

Stainless Straw Cleaner Cleaning Tube Brush

With the low temperature of the raw water inside the tube stack I doubt there would be much scale buildup. In the engine fresh water circuit it no inhibiter is used there could be scale build up
 
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