How to Add Corrosion Inhibitor

scatgo · May 13

I have a 100 year old heating system. I would like to add some Corrosion Inhibitor preferably without having to drain down the whole system. I am somewhat stumped on how to do this.

hot_rod · May 13

Do you gave a boiler drain, or any valve with a hose connection? Screw this on, open the valve wide open, pull the trigger. Takes seconds for it to inject in

pecmsg · May 16

Why after all this time do you feel it's needed?

Pumpguy · May 16

If you operate a 2 pipe steam system with condensate or vacuum pumps, PLEASE DON'T ADD THESE PRODUCTS AT THE PUMP'S RECEIVER TANK.

These products typically are high in alkalinity, and this high pH will corrode the bronze pump impellers and other working parts in short order.

It's also a good idea to monitor the pH of the returning condensate and maintain the chemistry on the mildly alkaline side.

If the condensate goes acid, lower than 7 on the pH scale, you have an acid condition that will corrode the cast iron and steel parts of the pumps and return lines.

I have seen both conditions many times when servicing this equipment.

EdTheHeaterMan · May 17

Is this on a steam boiler or a hot water radiator boiler? Those first few non-answer replies (what not to do) are related to steam. Only @hot_rod gave you a good option.

I used a pump to pump chemicals into a boiler system without draining the system. two different designs.

Silver King Chemical Force & Suction Pump - SK11, Brass

EZ Flush electric pump kit is a new brand that is available in a compact kit that includes the pump and hoses. The chemical that it comes with is for tankless water heaters, but you can add your own chemical and run the chemistry thru the boiler for 30 minutes or so and see what happens. I have used a different kit and ended up throwing out the crappy water several times before I liked what I saw coming out of the boiler. Then I added the proper chemistry to get the proper pH for the boiler and let that run for about 15 minutes.

I just needed to be careful to thoroughly clean my kit after a boiler, so I could use it on a potable water heat exchanger the next time I needed to.