Air relief on pressure filters 1

[Catcher66]

Is an air relief valve necessary on pressure filters served by wells with submersible pumps? Since the check valve for the submersible pump maintains pressure on all of the piping above the static water level, it seems unlikely that air could be introduced this way.

Will gases come out of solution while under system pressure? Are there other ways for air to enter the system that I am overlooking?

 

[sbush]

The most likely source of air is the backwash-to-waste line during backwash. Usually, the water level in the filter drops to a point just above the overdrain collector invert during each backwash event. This scenario might not be true, however, if you a creating backpressure with a throttling valve or flow control device installed downstream from the filter to the drain.

Another occurs when the filter is drained for maintenance or inspection. The air needs to be released completely prior to restart.

Piping repairs, and leaks can be another source.

S. Bush

http://www.water-eg.com

 

[cub3bead]

If you assume the check valve will never leak down and you deal with the issues sbush brings up you could but why take the chance of damaging the equipment. BTW, use a combination air release/vacuum breaker valve.

 

[bimr]

Many states now require a combination air release/vacuum valve installed on the well discharge to prevent a possible vacuum condition in the well discharge line when the well drains back. Valmatic sells a well service air release valve.

http://www.valmatic.com/wellserviceair.jsp

What is your objection to the air release valve?

 

[Catcher66]

I am in support of installing the valve. I asked the design engineer to add it, but he thought it simply added cost without providing any benefit.

 

[bimr]

I would say that the air relief valve is mandatory on the filter(s). The extra cost(?) is minuscule. The filter manufacturer should be supplying the valve anyway.

And don't forget to put in an the well service air release valve too.