Chalk in model boiler tubes.

[T James Ives]

I have an English made model by Stuart of a mill engine.
It has a horizontal copper boiler in a steel casing with just the top of the barrel showing. Under it in the firebox are three copper pipes looped back for extra heat. These must be chalked up by now as for a long time it was run in a hard water area and I did not use rainwater ( being 9 or 10 yrs old at the time.)

How do I clean these tubes. The only access is through the pop valve thread about 1/4" dia, and a couple of water guage threads in the end which are 3/32" gas.

Short of unbrazing the tubes what chemicals can I safely use in copper?

I am away for two weeks so any reply from me to yours will be a while.

Trevor

Trevor

[K D Redd]

Try vinegar.

Kent

[ncseverson]

Use vinegar, but only for around 30 minutes and make sure you flush all the vinegar out when you're done.

[T James Ives]

Thanks for your replies.
The tubes are, I think, solid with it but I will try vinegar ( perhaps a little warm)

Trevor (Back from a break 5 days early through solid storms and a field full of mud!)