July 2018

Extended Life for Diaphragm Expansion Tanks

...part 2
In the May/June, 2018 issue of ICM, I wrote about using a valve configuration similar to what is used on commercial hydronic systems to facilitate checking the charge on these tanks and to perhaps extend their useable life. In my hurried rush to get this article completed—yes, I installed the isolation, boiler drain valves, tank and took photos while on a service call to repair a water leak on the day of deadline!
What a coincidence, a waterlogged diaphragm tank, with an active leak from the relief valve giving me another metal balloon to add to the dumpster!
A waterlogged diaphragm tank, with an active leak from the relief valve, gave the author another metal balloon to add to the dumpster.

A waterlogged diaphragm tank, with an active leak from the relief valve, gave the author another metal balloon to add to the dumpster.

The following day, while looking at the pics I submitted, I realized that the feed valve and backflow on this heating system were incorrectly installed! OOPS!!! The boiler feed valve installed in this manner would never sense a drop in system pressure with the backflow preventer piped downstream of the feeder.
Many noticed this. Glad to see so many professionals out there paying attention!
The following day, I was in the supply house picking up parts for a system repipe and noticed some nice combination isolation/drain valves they stock in many sizes, (except ½”). So I go over to the counter guy, and ask if they make this combination valve in ½”. Well, he shows me that not only is it available in ½”, but they even make a ½” expansion tank service valve: Webstone part # 41672. This is the Webstone valve I would use on all new installs.
Webstone Part #40612: this is the valve I would use on all existing tank replacements.
This is a half inch expansion tank service valve.

This is a half inch expansion tank service valve.

Use the Webstone Part No. 40612 valve on al  existing tank replacements

Use the Webstone Part No. 40612 valve on al
existing tank replacements

For some reason, none of the supply houses in my area are stocking these 1/2″ valves at this time. I had these ordered in. I hope that I will start seeing these in stock soon (hint, hint).
Use the Webstone part No. 41672 on new installs.

Use the Webstone part No. 41672 on new installs.

Use the Webstone Part No. 40612 valve on all existing tank replacements.

Use the Webstone Part No. 40612 valve on all existing tank replacements.

I feel these valves would be a great addition to truck stock, and if utilized during a failed tank replacement, or added during a new system installation, will be very beneficial in checking the tank charge during annual maintenance or during hydronic component repairs.
Stay safe, Wayne  ICM
Wayne Lawrence is an instructor for Oilheat Comfort Corp. OilHeatComfortCorp.com
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