Ideas on cleaning Munchie HX?

Keith_8

We ran into a similiar last month. Not a tight heat exchanger like the Munchkin it was a Weil McLain 680. The system is 15 hydro air units, copper mains and steel piping in the boiler room. No air eliminator, traditional expansion tank, base mounted pumps on the return side of the system and 25 auto vents on the airhandlers and mains in the attic. The pumps were sucking air into the system and the expansion tank was piped to the system where it had no chance to accumulate any air. Not to mention autovents should not be in a system where expansion tanks are used.

The water in the system was literaly like mud. Before we changed the piping,pumped away from the boiler, added the rollairtrol and repiped the expansion tank properly we had to get the system water straightened out.

We dumped the entire system.
Refilled the system with water, fired the boiler, manually opened all of the hydro coils.
Ran the system for an hour and a half this way untill everything came back HOT.
Dumped the system.
Filled the system with clean water and added (3) quarts of Tri Sodium Phosphate Substitute, found at Home Depot probably about $40. Home Depot doesn't sell the non subsitute version but a paint store should still carry it.
Vented the system and fired the boiler.
We left this in the system for about a week and a half.
When we dumped the system I could not believe how clean the water was. Unbelieveable.

I would also add a stainer to the inlet of your heat exchanger.

Good Luck,
Keith

Leo G_101

OK

got the call about 10 days ago, Munchie sounds like it is making popcorn! Black iron mains, LOTS and LOTS of RUST in the system. Put a conservative dose of hydronic cleaning chemical in last Tues. Just spent 12 hours today trying to clean out everything. Did not work, still a lot of popcorn being produced. Wondering ifn any one else has had to tackle this scenario. Thinking either triple the chemical clean dose
(but at about 600 bucks for this amount of chem. seems like a lot) or pulling the wee beastie out to the driveway and try to flush it with a garden hose or some such thing.

Any suggestions would be very welcome by myself and my client.

Thanx!

Leo G

ScottMP

Wow Leo

Sorry to hear it but good for you for sticking it out.

I think I would dis-connect it and flush it out side. Maybe pump a solution through it ? Get a bucket and use a transfer pump to suck from the bottom of the bucket and then let the return dump in, maybe you'll see and trap the stuff coming out.

Did you install a sediment trap ? I've never seen this but I guess its wy munchkin says to install on ( at least they used to ? ).

How about a solution if Iron-Out ?? Anyone know if it will bother the stainless ?

Good Luck Leo.

Scott

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Mark Eatherton

Popcorn ehh....

A LONG time ago, I was told by the American Grandfather of modcon boilers (Hi Pete) that magnetite and these close tolerance boilers WAS going to be an issue... Not exactly sure if THAT is exactly your problem, but if it is, I'm thinking a yank and quick connection to a local fire hydrant (backwards) should cure that problem, Flush it backwards first, then forwards, then backwards, then forwards and so on and so forth until she runs clean.

However... and there's a HOWEVER in every crowd, it sounds like its limed up to me, in which case flushing ain't gonna cut it without the aid of some fairly strong and concentrated acids.

Once you get 'er pulled, do a visual on the outlet and inlets to the HXer and see what you see. Could be its only a problem at peak conditions when all the water in the system is heated up, and the undersized expansion tank kicks in, causing the relief valve to do it's thang....

Let us know what you find.

ME

rich pickering

Leo

you could try some rydlyme. If you have a spirovent, don't forget to check if it is plugged. Especially after you clean the system.

Leo G_101

More info

ifn I had my camera yesterday, you would be looking at a pile of rust particles, from fine to 3/16 in length. The flushing of various heat exchangers produced a very dark coffee looking stream that would clear up to brown to opaque to clear. Then when I returned to each heat exchanger in rotation (pool/spa/DHWT), there would be the same progression, just less time in each stage. By the 12th hour, after purging complete system, trying to clean the B&G air vent, etc., only the opaque showed, before clear running water.

This is a 199M, and when firing on high, at about 90*F onward, the popcorn dance is on! I took the pressure relief off, and the channel had a very good amount of particulate. Also, the tridicator had been located on the supply, and after removing that, I stuffed my finger into the tubing and could feel more partickles, and the finger came back very black. This was after about 6 hours of purging!!!!!

I am seriously thinking of ripping that Muncher out and blasting it, then running TSP or like for a good week to try to get the residue out. Anyone know if TSP is "allowed" for stainless, iron, copper, and pex?

Leo G

PS - oh by the way, these guys used DWV copper, which I have been noticing a lot lately, so I cannot use any press fittings, as PP does not support pressing DWV copper! I have told the homeowner to get in touch with the city inspectors and ask why a non-pressure tubing was approved for this application....

Also Prof, we have very soft water here in Vancouver, so I do not think that lime is the problem. Maybe a baking of the iron rust to the stainless? Could the HX be buggerred? For the homeowners sake, I hope that I do not have to change the three year old boiler, as they are already saying that they should have stuck to forced air!

Leo G_101

Keith,

have approx. 75 to a hundred gallons of water in the system (based on a gallon for 100 feet of 1/2" pex, plus other tubing). How much TSP would be needed for this amount?

LEo G

Leo G_101

Thanx Scott,

what solution would you recommend? I think a buddy has a pumping system like the one you mentioned.

Leo G

Leo G_101

Yeah Rick,

The B&G air vent is totally plugged. Tried cleaning it, but was probably unsuccesful.

This system was installed by one of our Hot Water Heating Commitee members, and is not to HTP design. Completely Pri/Sec, with the air vent on the floor heating main only! Partial Vision one, floor heat only, all the high temp loops are run off of relays as opposed to a vision 2 control. So many things done wrong that I got very upset while the homeowner was there (my bad). A real bastardization of protocol, and of course, he no longer uses this boiler line, as he has had nothing but problems with it! Gee I wonder why......

New policy effective now.... when I get a no heat call for these high effecient boilers, I will do my best to get them going again, but if they are not installed properly, there is no warranty on my work, and I will not work on them again, unless I am allowed to redo them as instructed by said manufacturer. I am tired of carrying other peoples bad installs on my shoulders!!!!

Leo G

hot_rod

I doubt TSP

will do much good. It's basically a strong soap. If in fact you have hard scaled surfaces I would try Hercules Sizzle. An acid based product, safe for DHW use even. Run it for a few hours, flush and buffer the ph if needed.

But more importantly is how to prevent future occurences? You sure it is not a makeup water induced issue?

Another option would be an isolation heat exchanger, but that just moves the problem to a different location. Although one in-capable of making popcorn sounds

Sounds like an ideal HX to sacrifice to the hydronic "need to know" cause. replace it and cut the old one open for all to see.

hot rod

Keith_8

TSP

1 quart,

In my case the water flowed like mud but I did not see any solids to speak of.

As one of the other guy's mentioned, since this is a fairly new install, how did this situation occur? It's one thing to clean it up, it's another to keep it that way.

I hear you about taking on someone elses poor install or a poorly maintaned system is just as guilty. Although you hate to be the bearer of bad news what else are you supposed to do? A poor install is just that, a poor install. No amount of band aids is going to make it right.
The same goes for a neglected system. A couple of bucks is not going to put the system back in top shape. If it was they would have spent the $ a long time ago.

Sometimes I think as consumers we think if we keep asking the same question eventually we'll get the answer we want ($). Not the case, eventually we find someone who tells us what we want to hear.

Keith