Steam condensate tank defective float switch.

JHK

We have an account with an older shipco condensate tank and the float switch no longer works correctly. The water level will be as high as going out the overflow and the float switch will not close and if you adjust the cut in set screw than the cut out is too low where the pump is sucking air. Whatever adjustment I made to the cut in the cut out would be too low and if I made an adjustment to the cut out the cut in would be too high. There was no consistency.
The problem happened after the tank was drained down to replace the pump that had a pump seal leak.
The float switch is an older square D 9037 flange mount not a threaded type float switch. I spoke to the local shipco rep and they still can get the float switches but are made to order and the lead time is weeks, this version of the 9037 is made for shipco so the design is different than other 9037 square D flange mount float switches.
My idea for temporary operation until the correct one comes in is to remove the sight glass assembly the glass length is approx. 20”. Install 1/2” to 1” couplings with black iron nipples and 1” crosses and install a McDonnell Miller 61 LWCO to turn on and off the pump and then re-install the sight glass at the end of the crosses. Is there a better way?

Jamie Hall

Well that would work. You may need a relay or a contactor for the pump, though — the 67 can't handle all that much current.

While you are at it… do yourself and your boiler a favour and convert the system to a boiler feed pump system.

JHK

It is a boiler feed pump system. This is one of the condensate pumps that pumps into the boiler feed tank that feeds the boiler.

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1828481#Comment_1828481

So? OK. There are any number of simple float switches — usually for sewage or sump pumps — which would work if you can figure out how to mount them. If this is just a receiver tank, it doesn't need to be sealed.

JHK

https://forum.heatinghelp.com/discussion/comment/1828477#Comment_1828477

Just responding to the part that said do yourself and boiler a favor and convert the system to a boiler feed pump system.
Don’t know about using items designed for sump pumps I would not trust they could handle the temperature even if it is only temporary.

109A_5

Hello JHK,

Assuming the float is working correctly, since the contacts look accessible, I would have dressed then up a bit with a ignition points file or a burnishing tool and flushed the debris out with contact cleaner, It may survive to the replacement time.

Pumpguy

@JHK, the float switch you show in your picture is a now long obsolete Square D bellows type seal flange mount float switch # 9037-CG 21 or similar. You might still find one on eBay, but are very expensive.

The problem with these is the soldered sheet brass bellows which seals the linkage pivot. When the bellows breaks, and at some point it will, there is no way you can repair it. At least I can't.

Also, the linkage pivot is a pair of gear teeth sectors which I found very difficult to adjust.

The flange dimension is 6.5" OD with (6) 0.44 holes equally spaced on a 5.75" bolt circle.

As a substitute, you can make a 6.5" diameter, 3/8" thick steel plate, drill the six (6) holes as above described. Now drill and tap this plate somewhere near the center for 1/2" pipe threads. If you offset this tapping, you have a number of positions to mount the pivot bushing; up, down, right, or left.

The screw - in type float switch is mounted on a 2 1/2" X 1/2" iron reducer pipe bushing. Remove this bushing, and thread the switch's brass pivot bushing into the 1/2" pipe tapping in the adaptor plate.

I do this all the time and its a perfect conversion.

Edit:

I see your switch flange has its OEM holes welded up and other holes drilled for a different arrangement. Make your adaptor flange as I described, but with mounting holes to match your stud pattern.

I have seen SHIPCO equipment almost since they began production, and have never seen this type of float switch on their stuff. I'm guessing this is some sort of field modification.

EBEBRATT-Ed

I agree with @Pumpguy rather than wait for an outdated switch make a new plate. A machine shop or fabricator can do it if you don't have the tools, get the newer style switch and be done with it. You will probably need one from Shipco or make one.

Buying a LWCO to make the temp fix will cost a fortune

Pumpguy

While still on the subject of this float switch and converting to the screw - in type, be sure you choose the Form Z20 type. The non-Z20 type uses a 3/16" Buna quad ring to seal the pivot rod. Buna is suitable for use with water and most petroleum products, and is good for 220* F. temperature.

The Form Z20 uses a Viton quad ring seal which is also good for water and most petroleum products, and is good for 400* F. temperature. These are longer lasting in high temperature applications.

The problem with both of these elastomers is neither is recommended for use with Amine based boiler water treatment chemicals.

A recommended elastomer for use with Amine based boiler water treatment chemicals is Ethylene Propylene Rubber, EPR, which unfortunately the switch manufacturer, now Telemecanique, does not offer. EPR is good for up to 300* F. EPR elastomers are not recommended for use with petroleum products.

When these quad ring seals begin to leak, these 3/16" quad rings in EPR elastomer material are available from McMaster Carr in quantities at a very low cost.

Due to this Amine compatibility issue, I have had customers require that I furnish condensate pumps with EPR seals. Shipco is one pump manufacturer that I know of that as standard uses EPR elastomer shaft seals on all their condensate pumps.

As a practical matter, I have never seen a Buna or Viton shaft seal that failed due to the presence of Amines. I guess this is an issue of Amine concentration, PPM. I have asked several suppliers of Buna and Viton elastomers at what concentration would Amines cause breakdown? So far, nobody has been able to answer this question.