Boiler limed up.

[spotts]

I have a friend with a Cast iron Weil Mclain CG boiler that is starting to rumble because of lime in the HX. It's 15 years old, and only on 12-15 gr. hard water, so I doubt it's real thick. Have any of you ever tried to remove the lime with Muriatic Acid or that less toxic replacement stuff?
I don't know the effects on the Cast iron, or gaskets, or especially the PH of the boiler, if I gave it a try this spring.

[hvacker]

Yes but it's worth it to use an inhibited acid for this purpose.
Use a small acid pump and you'll save time but the acid can be poured in and refresh when it looks like it has stopped working.

A boiler other than steam should not lime up as there are not enough minerals in an initial filling and the small amount of makeup water to create this problem. New water was probably being added for awhile.

I'd look to a waterlogged expansion tank, a bladder type tank that either has a bladder leak or has lost it's air charge, or a leaky relief valve. Anything causing new water to be introduced to the system.

[spotts]

I just straightened out the piping, Pumping away now, service valves, supervent, new exp tank. Now were down to the boiler.

[ct_hvac_tech]

We use this chemical called 8-way treatment that does a pretty good job of getting rid of scale, etc. I will try to find a link. System 2000 actually reccomends using it even on new installs.