scale buildup

lchmb

Looking for suggestions to combat a serious scaling issue in a commercial boiler setup. There are 5 Viessmann boilers tied to a multi temp system. 1 large air handler, some base board, and a number of plate exchangers (large) that heat a pool. I am looking for suggestions on what treatment to use and how long to leave it in the system. Should I be concerned with plugging heat exchangers? Will it damage circulators or should I just plan to replace them...Thanks for any thoughts on this...

After the scaling issue is addressed, the water will be replaced with a 60/40 preblended antifreeze to help with water issues...

hot_rod

Scaling as in hard water?
The only time you should see limescale type deposits is when the system has a leak and takes on makeup water.

If it is just dirt, oil, flux, misc piping gunk, a hydronic cleaner will work, they are basically a strong, non-foaming soap.

If it has hard water scale look at Hercules Sizzle, an acid based cleaned.

I think some of the hydronic chemical companies will take a sample you mail them and do an analysis. That is really the best way to determine what you have in the system and what it needs to clean it out.
You can spend a lot of $$ on the wrong cleaner and get little if any result. The soap based cleaners will not touch a hard water scale, if that is what you have.

60% glycol? That is a really strong % unless you expect to be pumping cold fluid well below 0° conditions? Be sure to check your pump spec with strong glycol %s.

lchmb

Thanks Hot Rod..actually it's 60% water...figuring roughly 10 degree temp. As far as the scaling it is a hard water issue. This place has had nothing but issues since the system was put in and are now asking the company I work for to address the problems. I've never seen scaling this bad in a system so have lot's of worry...

SWEI

Is there an auto-feeder on the system? Turn it off and see if the system holds pressure.

Henry

If the heat exchangers or plate heat exchangers are getting scaled, it could be a problem of pump selection. We have been replacing boilers, brazed plate heat exchangers because some guys used a 40 deg delta T. This causes insufficient velocity in the heat exchangers which the water leaves the suspended solids causing failures.

SWEI

Small passages (in any kind of HX) do not play well with hard water.

hot_rod

Yes, many of the problems we see start from the water quality. Noise, over heating boilers or HX, poor performance, early failure and on and on.

Unless the fill/blend water is incredibly hard, the inhibitors in the glycol should handle some hardness.

If a fill system is connected, and in the on position a leak in the system would show up as a diluted glycol %

It would be tough, not impossible, to scale up the system just from the first fill, with a water glycol mix?

lchmb

Thanks for the comments...Like i said we have adopted a system that has been ignored since it was installed roughly 5 years ago. The scaling is the worst I have seen (they have had major issue's with burst pipes, leak's and what not). A sample has been taken and sent out to see exactly what I am dealing with. Once that information is received we want to remove what's there then find a way to keep it out. Of course, I dont want to take on a system that is to far gone and end up owning it.

hot Rod, the reason we were asked to look at it, last winter they had constant "no heat" situation's due to boiler temps spiking. The history showed this to be the only error code for 2 months...