Rust in boiler water

Drew_2

How long has the glycol been in the system? When was the last time it was tested? If tested, what were the results (% of PG and pH of fluid)? What water was used in the system?

Dave_61

Rust in boiler water

We have a seven year old copper tube boiler that has a cast iron header on the heat excahnger. We had been having alot of noise with the boiler, so 2 1/2 years ago, we completely had the whole boiler loop repiped in 2" copper and added an Ergomax reverse indirect tank as a buffer tank.

There are 2 manifolds that come off the boiler/ergomax loop....a supply manifold with several 007 taco pumps and a return manifold.

These manifolds were carry-overs from the original setup and are composed of black iron pipe. Everything else (piping to hydroair units, etc) is copper piping.

The primary boiler loop had been black pipe also, but when we repiped 2 1/2 years ago, we replaced everything in that loop with 2" copper (except for the iron pipe that is threaded into the heat exchanger for the boiler.

The pump in this loop is a Taco 0010.

The drain valve in the primary boiler loop had been dripping for a while, so I decided to replace it. When I unscrewed it, I got about 2-3 tablespoons of rust flecks, etc. In fact, the back side of the drain valve (that faces the boiler water) was practically clogged with pieces of rust. Some of the flecks were the size of your pinky fingernail. However, the water that came out the circuit after the pieces of rust came out was clear.

Does this show some kind of problem that we are having with that much rust after a couple of years or is that a normal occurrence? We don't seem to be having to add any fresh water, which I know is a cause of rusting. Also, we have some glycol in the system...probably 25-30%.

Thanks.
Dave

rob brown

rust

dave, are you sure there are no leaks/makeup water? there are feed valves with built in meters(or a regular water meter piped into the feed line) to monitor how much makeup water is being added. if the system is tight, piped with all copper and iron pipe, then the water you drain would come out black. like black tea. this is the good stuff, all oxygen removed, full of iron, but not iron oxide. you need the oxygen for that. you make no mention of the type of emitters. any chance there is non-barrier plastic tubing anywhere in the system? if so then a heat exchanger is probably in your future. rob