Low water (in glass tube) but boiler works fine

samdobbs

Hi my boiler control model 47-2 seems to work fine. But the water level appears to be very low (about 1") even after weekly release. The refill process just stops at the 1" mark. Please see picture. Should I worry? Is there something simple I can do e.g. may the float is bumping up against something? Many thanks in advance!
Sam

Intplm.

That may possibly be the way the water level is set up. Can't tell from the angle of the picture but the McDonnell And Miller control has a line on it that coincides with the water level.
When was the last time the boiler was serviced? If its been a while, I would have the boiler serviced by a pro. A correct water level is a important factor on your boiler.

delcrossv

If it hasn't been disassembled and cleaned since '03 best bet is it's full of crud. As it's a critical control, you should have a pro look at it.

Big Ed_4

There is a differential between water feed on and water feed off. You may have caught it just before feed on . The line on the side of the casting should be level to 1/3 of the glass / feed off...

Flush the blow down valve on the LWCO every two weeks ...

Long Beach Ed

You understand that the 47-2 is a minimum water level safety control and not an operating water level control?

It's designed to maintain the lowest safe water level.

You are expected to fill the boiler manually to the normal operating level.

samdobbs

Many thanks for your responses! Sorry I couldnt figure out how to respond to each thread separately

BigEd_4 -- I do flush the blowdown valve religiously. Whenever I do, the level drops to zero and then immediately fills back up -- but only to 1.0" -1.2" Hence my conclusion that water flow in is fine but something is preventing "normal" fill which should be 3" or so?

Long Beach Ed -- Yes, I realize the 47-2 is a low water *control*, but I did not know I need to manually fill to operating level. Any suggestions on how? I dont see any valves to open or keep open. I did watch this at the 4:51 mark should I try? https://www.youtube.com/watch?v=ZyRpiKf2p58

delcrossv and intplm -- the fact that it fills and operates suggests it is not an inflow issue?

Thanks!

dabrakeman

Have you looked at the manual? Attached is a link. Take note of the troubleshooting list on page 11.
s3.supplyhouse.com/manuals/1350993347279/84563_PROD_FILE.pdf

Sylvain

samdobbs said:

I dont see any valves to open or keep open.

Pictures of the whole setup would allow us to point to refill valve.

samdobbs

Yes of course. Here they are -- the only water inlet and outlet are marked by arrows I don see *any* other ingress or egress (except the yellow handle on the 47-20






I did get a 1/4" increase using the hack at 4:51 in this video

https://youtube.com/watch?v=ZyRpiKf2p58

Sylvain

samdobbs said:

I did get a 1/4" increase using the hack at 4:51 in this video

So that is one way of doing it. Otherwise you could add water with a garden hose connected to the faucet pointed to by the red arrow.

Otherwise, for a permanent setup, plumb a bypass with a good quality valve between entry and exit of the 47-20. Good quality valve because even a little a leak would cause an overflow of the boiler.

samdobbs

Follow up -- after sneaking more water in, I find the level drops back down to 1" in the sight tube! Might this mean a leak in the boiler or elsewhere? Any suggestions on how to debug?

Recap --whenever yellow blowout is used to flush, water fills up to 1" in sight tube but never higher. Boiler works fine radiators heat fine, no operating troubles. Only anxiety at water level never higher than an inch