model 47-2 lwco

Big Ed

Don't put your name on adjusting a float type lwco.

Go electronic ...Better to let him then you pay....

Fix the leaks and then you don't need a feeder.....

Michal

model 47-2 low water cut off question

a friend has a model 47-2 low water cut off / automatic feeder on a old pacific steam boiler in his apartment building. His service guy supposedly came and cleaned out the strainer and the float, since he has done that, the water level is one inch lower then what it used to be. The level of water is just at the point where 1/8" makes or breaks the circuit. He has to manually ad more because it stops just shy of where the burner will operate, but its right in the line. my question is is there a adjustment on the 47-2 feeder side, i see there is a screw there, the switch was replaced last year. Does anyone have any input on this, I was going to get a gasket and take the float apart and see if something is bent like the arm, he really does not want to replace it since its 2 years old and expensive. any help would be appreciated

[Deleted User]

I would not touch

the screw. Sounds like the float is hung on something. Maybe an old piece of gasket. There is not much room between the float & sides of the bowl. The 47-2 is a proven control. Keep it. There aren't many large buildings with zero leaks.

Michal

its not the leaks

its not the leaks we are worried about, rather it is the fact that he has to go there every 3 or 4 days and bump up the water level on the boiler so the burner will run, thats the issue, i am going to get a gasket and try to take the lower 1/2 off and clean the inside of the bowl. hopefully its just getting stuck, and not feeding more water. I agree this is the cadilac so why f(*k with it, but it wont fill to the way it used to and let the burner run, thats the issue

Unknown

The leaks should make you worry

I know it's a pain in the **** to keep going back to bump up the water level , but just think about what all that makeup water is doing to the system , the inside of the 47-2 , and the boiler itself . I've taken out a few steam boilers that have been in operation less than a year because of a leak , and noone saw it because of the auto fill .

Steamhead

Mike, another problem with the 47-2

is that the valve body is made of iron rather than brass. I've seen some of these rust up after only a couple of years and start leaking. This didn't seem to be a problem in the old days but it happens rather frequently now.

If that were my boiler, I'd switch to a probe type LWCO if there's a suitable place to mount it (check with the boiler's manufacturer) or a #67 float-type LWCO. Teamed with an electric feed valve having a brass body, it should give you trouble-free service. Some of the latest feed valves have water meters built in so you can track the system's water consumption.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

EBEBRATT-Ed

It's possible that there is nothing wrong with the control.It could be plugged or partially plugged piping between the feeder and the boiler (in the make-up line) usually where hot meets cold at the return header.

[Deleted User]

Sorry Steamer.

Pacific Boiler Company is no longer around to ask. I would be real careful about using a 67 as the primary LWCO on any commercial steam boiler. A 1/2 cup of mud can be fatal.

Not saying don't fix leaks. But leaks don't kill the old boilers as fast as the new ones. The water meter is a good idea.

I think someone missed something during the last work. Why not try to fix it first? Would be nice to know what the final fix is.

Steamhead

If it's a big old Pacific

it might be bigger than the 47-2 was designed to handle (5000 square feet EDR). Mike hasn't posted the boiler's rating yet but it should be checked out. We all know that just because something has been there for years doesn't mean it's right.

I'd favor the 47-2 again if M&M came out with a brass-bodied valve for it.



To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Michal

input

the input of the boiler is 700,000 btuh an hour
5 gph total, i will probobly take the thing apart this weekend and clean it out. see what that does me, just have to get the gasket from a supply house. i do not feel like making one

Jack Ennis Martin

lwco for boilers

Do not I repeat do not under any circumstances adjust a Macdonnell if you look at the switch it has what looks like nail polish on the heads -- that is because you never move them - ever. Where is the line on the boiler that is the lowest acceptable water level. If you cannot find it ask Dan if he has the original specs for this boiler ,it will have the demension for that level. Do not ever go below the lowest acceptable water level ;it is there for a very important purpose. Is the Mac. in the correct elevation for the boiler? You say it has been changed did someone alter the correct placement of the 47. If you change the level of the 47 even 1/2 inch this problem will occur. I would venture a guess -- when the control was taken apart the float was left to hang and the factory adjustment for the control was altered. The forty seven sees a need for water it feeds until the float postion is satified and stops. Once it stops ,the other side of the control allows the boiler to fire. Your control is stopping the boiler within 1/8 of an inch -- check that the new switch was installed correctly it sound like the switch is not level and is not "floating" closed on the mercury bulbs. Mercury is funny material it will not flow until it has to and it is hanging up because of the switch postion not being correct. A final thought ,I have in my travels, seen so many things that did not work because the tech. did not own a level or was too lazy to go to the truck to get one --- a 47 is very "ornery" if it is not plumb and true. If it is off even slightly ,it will not work. Check this out.
Good luck and once again :leave the adjustment to the factory ,if something awful happens and the control can be proven to be altered, you will be a world of trouble.
Good Luck and all the best.
Jack Ennis Martin

Calif. Curt

47-2 problem

The M/M 47-2 feeder does not have mercury switches. The #2 switch mounted on top is a mechanical micro-switch that is activated by a cam mounted on the control's linkage assy. The cam is adjusted (and set) at the Factory using an eccentric screw that will move the cam up & down as it is turned. Since M/M sells replacement plastic cams, I have to assume that they do not have a problem with a properly trained technician adjusting them.

As the water level drops, the cam is raised to disengage the micro-switch - shutting off the burner. Conversely, as the water level rises, the cam drops, and the switch is closed, allowing the boiler to fire. I suspect that someone has fooled with the adjustment of the cam, and it is not dropping enough to let the switch make.

By the way, make sure that you inspect the cam to make sure that it is not broken. Some of the older vintage feeders that used the #2 switch had a white plastic cam that would become brittle & break over time. If that happened, the LWCO will not shut the boiler off in the event of a low water condition. The newer cams are black, and are apparently graphite or carbon filled, and do not have the same cracking problems. Since the Pacific Boiler is probably pre-1970, it could still have the suspect cam in it.

oilman

i would put in and electonic lwco the one you have has no adjustment on it

Unknown

MM controls only good for 10 years

Replace it if it's older than that. Ask the factory about this.

I think the float might be a little heavy. Dirty or partially waterlogged.

Noel

[Deleted User]

Since you told

us the 47 is 2 years old & the #2 switch is 1 year old, obsolescense is not a problem. McDonnell changed the design of the 47, 101, & 51 Valve & Strainer Assembly in the late 90's. They had some real problems w/ them in 1999. The poppet fouled w/ crud from the incoming water & stuck in the closed position. The symptom was the boiler would go off on low water.

They changed the poppet to a looser design. Doesn't foul up as badly. It will cause loose water pipes to dance when closing though. Yours may be fouled w/ crud. If the 47 was laying on someone's shelf for a while, you may have gotten a bad one. Look on the V&A body for a date code. Will be in white. Letter for month & 2 digits for year.

McDonnell recommends replacement yearly. Not a big deal. Just remove the 4 bolts on the bottom of the V & A. Drop the strainer. Using a deep 13/16" socket, back out the old cartridge assy. Flush the assy w/ fresh water. Then reverse the process w/ new parts. McDonnell Part Number 310453 (CTRD-101). All parts are included. Not cheap. Around $70.00.

Boiler Guy

As Curt said

47-2 doesn't use mercury switches. Check the adjustment of the cam and make sure the locking screw was not left loose alowing the cam to move. If your float is "heavy", the control will over feed.