Boiler yearly up-keep

Jimbo_5

Actually, I had a problem with this boiler a few years ago (3 or 4) where the pressure relief valve kept running and running, the valve and expansion tank had to be replaced. Perhaps that added to this problem, or caused it. Is there anything that should be flushed through the system, or just fresh water? Also, should the burners or any other parts be cleaned periodically? You know, like a tune-up?

Jimbo_5

Boiler yearly up-keep

Thanks guys, I just swapped my 30-year old B&G 100 for a Taco 007. Went nicely. But, when I pulled the B&G off the boiler manifold, I found a great deal of black "sludgy" looking water. It was as black as ink, and stained my fingers the same way too. Should I have flushed the sludgy water prior to running the new circulator? It started a tad noisy, yet after a minute or so, after the air ran out, it was as quiet as a mouse. My question is this: These 2 boilers have been sorely neglected, and I want to bring them up to snuff. They are 1978-ish Weil McClain PCG-3, gas fired. What would be my best bet for yearly up-keep? I don't mind the work, if I was sure which direction to proceed in.

Weezbo

Yikes!

Oh O ....Oooops. Welcome to the Mr.Bill show in hydronics 101.:(

Argh... if you want the boilers to Live long and prosper, start with Flushing the system. a small book could be written on the subject,the gist of it is get the gunk out.

right now , you are a likely candidate to procure stock in Taco wet rotor circulators. do not feel bad... i just got my circs from the factory yesterday*~/:)

Perry_3

That black inky stuff is normal.... and what you want...

The black inky stuff is very fine magnitite particles coloidally suspeded in water.

Magnitite is the "good" form of oxidized iron. It is stable and a coating of it protects the pipes and radiators from red rust forming (the other kind of iron oxide).

It forms from Oxygen leaking into the system - which will react with the iron in the pipes and radiators.

A one time flush will get much of it out of the system. However, you will not get all of it out. In addition, the oxygen in the water that you use to flush and to refill will react with the iron to reform more of it (at least you want it to reform as magnitite).

The key to controlling the growth of it is to limit the amount of oxygen leakage into your system. In most cases this is almost directly related to the amount of water leakage - as the replacement water has a fair amount of free disolved oxygen in it (which is why fish and other critters can live in water).

After 30 years I'd do a flush and leave it be. Perhaps once every 10 years I'd do another flush to get most of it out. If you have a tight system that does not leak much that should be adequate. Doing an annual flush would probably casue more oxidation of the iron in the system and cause more formation of magnitite (in total) than if you did nothing as long as you have a tight system.

Perry

Empire_2

Hi Perry: Very informative:

Although I do not agree with your flush schedule and air is easily controlled in a properly designed system. Clearly you must be an engineer or chemist, but I personally would at least flush on a more frequent basis and also obtain proper PH to the manufacturers specs.

Just my .02, not looking for war of words.:-)

Respectfully

Mike T.

Unknown

Perry, I would agree with you that flushing often would add additional oxygen to the system and only cause further oxidation. As long as no further fresh water is added to a sealed system, the oxidation will stop when all the oxygen has reacted with the iron.

Another possible cause of oxygen in a system is periodic draining of a non bladder expansion tank to maintain an air cushion. In this case mostly nitrogen is left in the system after the oxygen portion has reacted. In my system with a non bladder tank, I fill the tank with helium instead of air. Besides being inert and nonreactive with metals, the helium has the further advantage of very low solubility in water. This prevents it from migrating from the tank and winding up in the radiators, eliminating periodic bleeding.