MAXON VALVE MAINTENANCE

[saparna]

I wondering if someone knew what type of maintenance could be performed in maxon electromechanical valves (double block and bleed) put in boilers. Also how reliable is the maxon compared to jamesbury ball valve for safety critical systems.

 

[ballvalveguy]

Hi Saparna,

Do the valves need to be FM approved. As far as I know, only Gosco

http://www.mclassvalve,com

has a double block and bleed valve that is FM approved. I would definitely put Jamesbury as a higher quality valve than Maxon. What maintenance needs to be done?

 

[danw2]

Maxon's web site is

http://www.maxoncorp.com/

The site offers installation guide downloads for all its shut-off valves.
Each guide includes a procedure for a periodic test.
One such test (of two in the guide), for the 4700 valve is below.
You should find the test for your specific valve.

Suggested leak test procedure for
double-blocking shut-off valves
(without vent line)
(a) Shut down combustion system per manufacturer’s
recommended procedure.
(b) Close manual valves A and B.
(c) Visually inspect to verify that shut-off valves #1
and #2 are closed.
(d) Remove the 1/4” pipe plug from downstream side
of shut-off valve #1. Install leak test apparatus.
Safely vent any trapped gas pressure.
(e) Open manual shut-off valve A, then close leak
test apparatus. Insert tube into a container of
water just below the surface.
(f) Open test apparatus and test valve for leakage.
As a guideline, valve should be tested for 2
minutes per inch of pipe diameter. Large diameter
pipes or long piping runs between shut-off valves
may need additional testing time.
(g) If valve testing indicates leakage exceeding 15
bubbles per minute, perform pre-operational
exercising as outlined on Page 6100-S-2 and
retest the valve. If valve continues to exceed
allowable leakage limit, remove from service and
contact Maxon.

 

[saparna]

thank you...we were planning to switch from maxon to jamesbury....For the Cv rating we had on maxon , we couldn't use the standard ball port rather we had to change it to fullbore. This lead to piping issues. Also we found that the actuator was aluminium, which in our plant is not allowed. When changed to SST, now FM approval on those valves weren't valid any longer.

Thus decided to stick with Maxon, but again we are having issues with all the mechanical junk i.e. clutch,limit switches, motor etc.

 

[herringchocker]

We have been using VCI valves with great success
Better that Jamesbury
Maxon valves are good in heavy commercial applications where they have only AC power
Pneumatic VCI valves have the highest shut-off rating of all approved valves

 

[jdraf]

From what I know of Maxon valves, they're specially designed for fuel safety shut off. Ball valves (Jamesbury, VCI, Fisher) require regular maintenance to tighten their packings otherwise you end up with fuel leaks. Maxon valves have all metal seats with no packings or elastomers. Ball valves are great for process flows of non-hazardous materials, but for fuels, I always recommend Maxons.

If you're having difficulty with the mechanical valves, they also make pneumatically operated valves which are very popular for furnace and boiler installations in petroleum applications because they're listed for hazardous locations and have iron, steel or ss bodies.

 

[saparna]

thanks