Help A.O.Smith PurgerTrol question

Steamhead (in transit)

is a butterfly-type balancing cock. It is piped into a bypass from the boiler outlet via the bottom of the Purger-Trol to the pump inlet, to run some hot water back into the boiler's return connection to prevent flue gas condensation.

The Purger-Trol itself appears to be an air separator, on which are also mounted the tridicator gauge and safety valve.

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geo_23

HELP A.O.Smith PURGER-TROL question

HELP A.O.Smith PURGER-TROL question

I have a question about one of the connections to the purger-trol (pt).
On a 30 year old baseboard heating system, there is an A. O. Smith purger-trol (pt) (part # 99127 [molded into unit] – new part # 9005089105) connected to an A. O. Smith boiler [model # MW 160P700] (the back of the pt is connected to the hot outlet.)

The other connections to the pt are –
1. Outlet at one edge labeled ‘system’ is connected to the inlet to the heating system,
2. An inlet in the center of the front of the unit (unlabeled) is connected to the domestic water supply (there is a Filltrol expansion tank between the pt and the actual supply line),
3. Outlet at the bottom edge labeled ‘fil-trol’ is connected to the inlet line to the pump on the outlet line from the heating system (this line has “something” in the line [looks like a check valve but not large enough and no arrows].)

Question – what is the purpose of connection #3 and what is the “something” (a plumber looked at it and could not identify it.)

Steamhead (in transit)

How about

posting a picture so we can see this thing?

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geo_23

picture

geo_23

picture

Here is the photo of the control area of the heating system.

1. White area with blue top at back is the boiler.
2. Brown rectangular area at left center in front of the boiler is the purger-trol.
3. Small blue area at lower right is the pump.
4. Pipe immediately above the pump is the pipe I am talking about - the fitting right above the pump is the 'what is it' fitting? Note that it connects to the 'fil-trol' opening at the bottom the #2 unit. (Testing – it is definitely NOT a check valve.)
5. White area above pump is the T connection between the #4 pipe above and the inlet to the pump.
6. Copper tube extends upward from #5 fitting and then extends away from the viewer into the wall (this is the return line.)
7. Fitting at center of unit #2 is the inlet line with the blue fil-trol air chamber at bottom of picture, a brass pressure reducer fitting then into a (blue handle) globe valve and thence to the domestic supply line.

Matt Undy

Is the mytery fitting a strainer?

geo_23

mystery fitting

Could be, I'll check.

Real question is - what is that /pipe/ for, it seems to be connected to the wrong outlet/inlet to the purger-trol?

Is it REALLY necessary or could it be removed?

[Deleted User]

What Steamhead said...

An air seperator/scoop like this is really nothing more than a fat spot in the horizontal line. The bypass serves two purposes. One, as Frank pointed out, is to raise the return water temeperature to get the boiler away from condensing temps as soon as possible. The other function is to keep flow rate through boiler high enough to avoid the water flashing to steam when a small zone is calling. This boiler is not a modlating boiler, and if the flow rate is too slow, it will rock and roll doing the low mass dance, and that causes your sphincter to do the mambo...

ME

geo_23

air seperator/scoop

Next question - what IS an air seperator/scoop (web page with explanation please)?
I am trying to isolate the heating system from the boiler so I can purge the system.
I have a valve between the boiler and a hose bib in the return line from the pump - there is now no other isolation valve.
Can I put a valve in that line with the air seperator/scoop?
Would that be the only valve needed in addition to the above mentioned valve for isolation?
Any other suggestions?

geo_23

air seperator/scoop

Next question - what IS an air seperator/scoop (web page with explanation please)?
I am trying to isolate the heating system from the boiler so I can purge the system.
I have a valve between the boiler and a hose bib in the return line from the pump - there is now no other isolation valve.
Can I put a valve in that line with the air seperator/scoop?
Would that be the only valve needed in addition to the above mentioned valve for isolation?
Any other suggestions?

Unknown

geo

look at your own picture, its that big thing with the expansion tank, relief valve and pressure gauge screwed into it. I have the exact same thing, its called a "purger-trol".

Dave

geo_23

bypass (balancer) line

Does the piping on your purger-trol look exactly like my picture?
If not can you describe the differences?
Can I put a valve in the line called #4. Pipe immediately above the pump (described in my original post) to isolate the heating system piping from the boiler?
Or is there a better way?

Unknown

geo

close, but not "exact", the funny looking thing above the ex. tank is a "Fill-Trol", and that allows water into your system by the air- pressure pushing against the diaphram in the tank itself, with this there is no "conventional feeder". to get the pressure-up in your system(if that`s your prob), you must increase the "bladder-pressure" in the tank. The bladder pressure should match your system requirements for static fill , Eg-12PSI. I`m not sure how to find-it on their website, but I have them here and would gladly scan, and send to you.

Dave