Skimming a Weil-McLean Steam Boiler

Rich L.

Ken, do you do this same cleaning method to new boilers as well or just old, "dirty" ones?

Thanks, Rich L

Br. Maximilian

Skimming our Weil-McLean

I've read Dan's "Lost Art of Steam Heating" section on skimming and maintenance of the boiler. The boiler water is dirty and oily, and bounces in the gauge glass, so wet steam is what we probably are getting. We've had the skim port piped already. Now the questions I haven't worked out yet: 1)how do I maintain a 180 degree temp without steaming? I only know how to call for heat from the thermostat. 2) If I clean out with TSP or a TSP substitute, is the regular water feed a "high pressure" water source that will "rinse" out the remaining chemical? Once I use the chemical, what then?

Dave_4

Brother Max,

Having installed many W/M steamers for the Newark Diocese, and being the factory authorized start up and trouble-shooter for W/M for many years I feel confident in responding.

Place Rosary Beads...

Kidding. Skimming is called for AFTER chemical cleaning first. The reason? You'll be skimming until Lent if you keep it up.

Hope this helps.

Let us know how it pans out

Make a solution of TSP using one 8 oz. cup per 100,000BTU's of input rating (found on the boiler label found on all boilers) and use hot water to mix the TSP required into a 5-gallon pail.

1) Drain completely whatever is in the boiler now - out.

2) Pour the almost dissolved TSP into the boiler block via the pop-saftey opening. Fill to the normal water line on the gage glass (about mid-point). with the TSP solution AND clean fill water via the fill valve/stop.

3) Fire and bring the boiler to ALMOST boiling. [This is accomplished by keeping one hand on the riser pipe atop the boiler. When it's too hot to keep your hand on - steam is about to enter the steam pipes] You do NOT want to allow the TSP laced water to steam into the piping. Doing so will loosen 50+ years of dormant scale and "junk" up inside the system piping making the task eternal vs. an hour or two.

4) Drain all the TSP and remaining water completely out of the boiler (the near boiler piping as well if drainable via a return drain or condensate receiver station dump valve.

5) Rinse by refilling, and heating, as in # 3 above (sans the TSP) and draining the rinse water from the boiler.

6) Then fill with clean water, fire the boiler to actually make some steam, and see what results. If no "water bonce" visible in the gage glass occurs, you're home free. If it bounces some, skim it!

7) To keep the water @ well under 212F (the point of steam creation) and skim, simply flip the on/off switch - to turn the burner on and off - while allowing the rate of feed water to balance with the skimming rate you find close to constantly consistent - neither letting the water flow so fats as to be cool - or, so slow as to allow major spitting and "coughing."

8) I've never witnessed a system that was so dirty I had to TSP three times, but then...



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Dave_4

Great question!

NO!

This is where the art of being a steam maven comes in.

Our policy - which worked extremely well for 30+ years was this:

If the boiler is well piped, we acquired the account and the vibes were good, we would TSP the boiler if it was less than ~10-years old.

If it was over 10-years old or piped wierdly, we would service it, but simply drain and flush the water sides annually - as part of the annual service regimen.

If we installed the boiler we ALWAYS cleaned it with TSP annually (as well as upon installation) - and added rust inhibitor to the make-up water. We aso told the client to NOT drain and flsuh the boiler ever! Simply blow down the LWCO (if cavity type) always while the boiler was steaming - about once a month and then, only until clear or a maximum of one gallon came out.

Because we ALWAYS replace the system air-vents and check all packing nuts and angle-stops for full open (or closed as the client requested), we found water addition to be a monthly chore in winter, and not at all in fall and spring. When systems are as "tight" as we made them, blowing down would simply add more harmful chemicals, making rust worse - not less.

Almost all steamers we serviced, installed or maintained were gage-glass spotless after a year of operation. This, due to being fussy about annual water side cleaning, as well as the favorable pH characteristics of TSP - and the alkaline residue it leaves behind.

A tight steam system with pH @ 8 or above is indeed the answer for steamers lasting forever. LWCO's too.

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Rich L.

Thanks Ken!

Thanks much Ken!

"Because we ALWAYS replace the system air-vents and check all packing nutsand angle-stops for full open (or closed as the client requested), we found water addition to be a monthly chore in winter, and not at all in fall and spring. When systems are as "tight" as we made them, blowing down would simply add more harmful chemicals, making rust worse - not less."

How often do you replace those steam vents? Would you please explain the "water addition" part further?

Thanks again Ken, great information!

Dave_4

Vent replacement...

We would not install a steamer unless they allowed us to change all the vents. On existing clients, we only change vents when the answer to the obligatory question, "How often must you add water since we were here last summer"? - Resulted in an answer of more than once a month. If that was the response, we would check all vents and all angle stop packing nuts, unions and valve position.

We also asked about room heating balance. Anything unusual typically resulted in a vent problem and we'd replace them all usually. We've seen 20 year old Gortons, provided the pressure was in the 1/2 to 2 PSI max - last 20 years or more.

System water consumption was the tell tale sign of blown vents.

If a vent showed rust stains anywhere on or around the orifice (Gorton's dominated 95% of the installs we serviced in NJ, since Gorton was within 10 miles of our shop - that was logical) the vent was replaced.

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Tom Hopkins

chemicals vs. only pure H2O

This is such an informative post, but it makes one wonder how to clarify the often stated - DONT USE CHEMICALS.

If i read your post right, and considered water purists, I would conclude the following:

FIRST Flush out boiler with just pure water following these instructions but without the TSP.

SECOND See if operation improves.

THIRD only do this process with TSP if necessary, and then ONLY IF BOILER IS LESS THAN 10 YEARS OLD AND WITH GOOD PIPING.

Am I getting it? Thanks again!

Tom Hopkins

pure water vs. chemicals

This is such an informative post, but it makes one wonder how to clarify the often stated - DONT USE CHEMICALS.

If i read your post right, and considered water purists, I would conclude the following:

FIRST Flush out boiler with just pure water following these instructions but without the TSP.

SECOND See if operation improves.

THIRD only do this process with TSP if necessary, and then ONLY IF BOILER IS LESS THAN 10 YEARS OLD AND WITH GOOD PIPING.

Am I getting it? Thanks again!

I WOULD LIKE TO ADD A QUESTION - what about those who say DONT change the water, not even once a year, to avoid new minerals or the necessity for another chemical like rust inhibitor?