Performance tip: Clean those strainers!

[Jim K in PA]

I would like to share my recent experience relating to neglect of maintenance. That would be my own neglect. I have a GARN WHS2000 interfaced with my HWBB system via a 50 plate HX. I installed the 50 plate HX in the fall of 2009 as an upgrade from a 30 plate that was undersized, and incorporated inlet strainers on both sides of the HX at that time (had none on the 30). I noticed some drop in performance toward the end of the 2009/2010 season in the form of increasing approach temp and the inability of the house to get warm. I "meant" to pull the strainers and check them at the end of the season, but with Spring fever in full swing, I was on to other chores and forgot all about the performance drop.

So for 2010 startup I blissfully fired up the GARN and switched the pumps on. Well, as you might gather, the performance issue did not fix itself over last summer Approach temps which had been in the 5-7 degree range when I first installed the 50 plate were now in the 25-30 degree range. Turning up the secondary pump to high speed did not help. So, last weekend during a brief period when the house was fully up to temp, I shut everything off and pulled the screen plug and screen. Here is the picture of what it looked like.

I cleaned the screen (took 5 min) and flushed out the HX (got tons of rusty much out) and now the approach temps are right back to as-new.

Just thought others might learn from my oversights.

 

[woodsmaster]

cant see the picture

 

[Jim K in PA]

Fixed the link.

 

[DaveBP]

Jim, are you using the manufacturer recommended water treatment and testing regimen?

 

[Jim K in PA]

Jim, are you using the manufacturer recommended water treatment and testing regimen?

Dave - yes I am. I am due for another test, and have the sample bottle and package ready to send off. Thanks for reminding me.

Last test came back overall OK, and just a small supplement and biocide was needed (fall 2009).

 

[bpirger]

Hi Jim:

This was the first time you cleaned and flushed since installation? I can see how there'd be crud from the beginning....but I'd hope it wouldn't be so much after the initial cleaning....which I understand you just did.

Was it really rusty particles or more like a goo?

Steve, any comments on if this is typical, or how often, etc and so forth from your experience?

I installed the 80 plate to get close temps...and looks to be about 3 degrees or so the few times I looked. Still haven't got all my sensors in....life keeps getting in the way. But I do have the strainers and easy access to flush out both sides. Garn 1500...fired up in Nov '10 for the first time. Not a drop of oil since first fire!

Thanks,
Bruce

 

[Jim K in PA]

Bruce,

This was the first cleaning since installation. It was a gooey sludge, and clearly was part bacteriological in nature. I used well-water to fill the Garn, and I know I have some low bacteria levels, but they get going well in the warm Garn, especially over the summer when it is ambient temp and not circulating. That is why the testing last season showed the need for a bacteriacide. I suspect that if I had cleaned the strainers right after the first season of use it would not have gotten as bad as it was. That's why I mentioned my forgetfulness in my first post.

BTW - I do have flush valves on them, and I did open them at the beginning of the season and not much but plain water came out. But, I did not close off the supply valve to the strainer before opening them, therefore I did not actually flush the screen, just dumped some supply water. Had I properly reverse flushed the strainer, I would have detected the low-flow condition right then.

 

[barnartist]

Do you have strainers because of an open system? I dont have any kind of cleaning at all

 

[Dave T]

Thanks for the the thread I need to check my screen. I put a Y strainer in and my system, I figured any solder balls or anything of that sort would hit the strainer first, I installed the Y strainer just before my circulator (low point of the system)with isolation on on both sides.

 

[woodsmaster]

Do you have strainers because of an open system? I dont have any kind of cleaning at all

I have a strainer in my closed systym.

 

[bpirger]

I have strainers on both sides of the HX and I used those webstone valves for quick and easy isolation and flushing. But I also found that the strainer can come out easily as well, and it seems like that makes sense to do. There's a very thin little "gasket" that seals the flange to get to the strainer. Did you have any issues with this gasket? I just don't know if it is the kind of thing that will leak if acessed more than a couple of times....though I'm sure one can obviously replace them.

Biological stuff, eh? I have well water too, and also I thnk I have small amounts of stuff in my water test...nothing to worry about for consumption I'm told...but yeah, you'd think it would be a great place to grow if I was a little bugger. So do you see any signs of corrosion inside the Garn? Can you tell if you have any sludge buildup at the bottom of the Garn, maybe from the critters? I know the Garn manual is highly concenred with bacteria...I just don't have any experience with how critical it all is. My next sample is due in the Spring. The one from December was negative for critters....but I bet that cleaning the screen in the spring will really give me insight into if there is growth.

I know I likely used too much pipe dope and I suspect I have a good deal of that floating around. Now, 1500 gallons of water is likely a great diluter,,,but I wonder if it'll come out. I didn't do a flush after the fill and running for a week...likely should. Solder balls, perhaps teflon tape pieces, etc. Who knows.... But that is what the strainers are for!

My plans was to hook up the garden hose to the one of my isolation ports and back flow through the strainer(and another hose to the other side to drain the flush flow) and HX to flush it out every now and then. But removing the strainer first to get a feel for the level of crud seems like a great idea....

Great tip Jim! Thanks!

 

[EricV]

Do you have strainers because of an open system? I dont have any kind of cleaning at all

I have a strainer in my closed systym.

Should there be in a closed system?

If so what is the general recommendation?

 

[Rick Stanley]

Here's mine. Click on signature if link's not live. I think strainers are put on both supply lines, as a matter of course, on flat plate heat exchangers regardless of system types.

http://farm3.static.flickr.com/2653/4020905410_01a51d20ea_t.jpg

 

[heaterman]

It's good practice to put a strainer on any hydronic system regardless of whether it is open or closed. It will catch the chunks of stuff that get into a system a "float" around until they find someplace to do damage. Inspecting your strainer on a regular basis will often serve as the canary in the coal mine and alert you to a problem before it becomes a major breakdown.

 

[in hot water]

Have that sample analyzed. Does it stick to a magnet when it dries? Install a pressure gauge downstream of the strainer to let you know when the flow is being restricted. Sometimes a dirt separator is a better device for systems that have an ongoing problem with dirt or debris. They do their job without obstructing the flow through them. A ball valve on the bottom allows you to flush them and check for problems.

You may need to get a good hydronic system cleaner, then keep the treatment up. The iron bacteria that I got stuck with was black and gooey and smelled like rotten eggs. It was tough to get rid of, it took a chemical cocktail, common hydronic cleaners and bleach would not kill it.

Turns out the well driller had the bacteria on his bits and drill rods and those had to be sanitized also as he was putting the bacteria in the wells as he drilled them. The bacteria would actually start eating the steel well casing and cast iron pumps in the heating system, wild stuff.

That could just be a sludge from oxidation and some of the silicas, calcium or other components in your well water. It's common to fine a gel like sludge in the bottom of water heaters when you drain them, typically not red colored as the tanks are glass lined. That looks like the same stuff, just with a rust color. Find a lab that specializes with water treatment, sometimes a nearby university can help with unique water analysis.

hr

 

[muncybob]

I have a whole house water filter installed on my main incoming line from our well. It's replaced every 90 days. With a closed system is there a need for further filtering?

 

[heaterman]

I have a whole house water filter installed on my main incoming line from our well. It's replaced every 90 days. With a closed system is there a need for further filtering?

That won't have too much of an effect on your boiler unless it's making up a large volume of water on an ongoing basis. The Wood Gun is a sealed system iirc, so it shouldn't be. This has more to do with what is actually going on with the water quality already inside the boiler, not so much the water coming into the house.