[an error occurred while processing this directive]
Posted by Tim D on November 25, 2004 at 07:21:41:
In Reply to: Cutting out on low water posted by Geo on November 25, 2004 at 03:57:43:
: Our company recently installed a Weil-McLain sectional boiler. It's around 500,000 BTU. What is happening is that the boiler starts to build steam and the water level drops, cutting off the boiler and then filling. It has a M-M 47-2 feeder/low water cut off. I have repeatedly cleaned/skimmed the water, checked the height of the header, hardford loop is ok, lowered pressure control to 1 PSI and still it keeps cutting out and filling. What ultimately happens is the boiler will be overfilled on shutdown when all the condensate returns. Had the boys from WM out and they say the chest cavity does not hold enough water and a condensate tank is needed. My thought is that when I closed off the header valve the same thing occured even though The steam had no where to go. Up come the steam, down goes the water.What's up? Can't sleep at night thinking about this one.
Geo, Not sure of your Weil Mclain series?, But When we installed our series 88, I constantly refered to installation manual for: proper "steam" header layout, header pipe sizes, steam control locations, boiler feed, surface skimming procedure, power burner options(high-low-high) etc.
From your note, it sounds like the boiler water level is the issue. Before making any changes, suggest reviewing surface skimming tap location and procedure. We had similar low level level issues every time pipe work was performed( one week or 2 years) later.
Not familar with your MM47-2 lwc, but the 47-2 manual has a maximum of 14" operating tapping height window. Are Quick connect fittings being used? There may not be enough differential between feed and lwc?
We installed a MM-150s on our boiler, plumbed to primary steam control tappings full size , 1"npt. This unit allows for separate relays for water cutoff & boiler feed pump with about 2" differentail.
Also, we installed a 50 gallon boiler feed system (tank + pump) to only feed boiler when the 150s called for water. 100% of our condensate return(s) & all soft city make up water(float inside tank) are directed to this boiler feed tank vs. directly into boiler. This way, the boiler water level is not overfilled by high fire or start up water surges. Instead, condenatate surge winds up in boiler feed tank until next high fire.
We Installed a small economy turbine water totalizer on make up water feed line to monitor boiler operation. We will use less than one gallon of make up water per week, which indicates there are no condensate leaks or open valves.
Hope this helps.
Post a Followup