Hose-bib circuit between pressure tank and BIRM filter

[JVance]

I am planning to replace my current WHF with a BIRM filter, and tee new plumbing for hose-bibs between my pressure tank and BIRM filter. In another thread, LLigetfa mentioning the possibility of reverse water flow through the BIRM filter with this arrangement:

Anything like an outside hose bib or sprinkler system before the filter can cause a reverse flow.

Assuming reverse water flow through the BIRM filter should be avoided, would a check valve after the tee to the hose-bibs and before the BIRM filter be sufficient to prevent this? Or should I scratch this idea and stick with the existing hose-bib plumbing after the filter?
Thanks!

[LLigetfa]

Let me add to what you quoted to help put it in context. If there is any sort of pressure storage after the BIRM filter (flexible piping, expansion tank), dropping the pressure suddenly and significantly before the BIRM filter can cause a reverse flow, the effect of which could be to unsettle the media pack. Something like solenoid valves on a sprinkler system could, depending on the volume, do that. A simple garden hose would not likely be a problem. I have one hosebib connection before my BIRM filter and several others after it. The ones after it run my soaker hoses on timers.

I also have a full port ballvalve Teed in just before the BIRM filter that I use to purge the line of iron buildup. When I actuate that valve, it does unsettle the media pack and I get iron bleed through to my softener. I periodically purge the line just prior to a manual backwash so as not to cause a problem.

If you install a checkvalve, then you will need to have an expansion tank as it becomes a closed system.

[JVance]

Let me add to what you quoted to help put in in context. If there is any sort of pressure storage after the BIRM filter (flexible piping, expansion tank), dropping the pressure suddenly and significantly before the BIRM filter can cause a reverse flow, the effect of which could be to unsettle the media pack. Something like solenoid valves on a sprinkler system could, depending on the volume, do that. A simple garden hose would not likely be a problem. I have one hosebib connection before my BIRM filter and several others after it. The ones after it run my soaker hoses on timers.

I also have a full port ballvalve Teed in just before the BIRM filter that I use to purge the line of iron buildup. When I actuate that valve, it does unsettle the media pack and I get iron bleed through to my softener. I periodically purge the line just prior to a manual backwash so as not to cause a problem.

Thanks for the information. I do not have an expansion tank after my current WHF, and the plumbing throughout the house is PEX. I don't know to what extent PEX flexes, so do you think adding the hose-bib circuit before the BIRM filter would cause enough reverse flow to unsettle the media pack? Or are there unaccounted factors that we simply can't predict in this case?

If you install a checkvalve, then you will need to have an expansion tank as it becomes a closed system.

Considering the answer to the previous question is "yes, the potential for reverse flow is enough to unsettle the media; you need a check-valve", what size expansion tank should I look for (1600 sq.ft home, 2.5 bths)? [nevermind...I found some expansion tank calculators online]

Thanks!

[LLigetfa]

Or are there unaccounted factors that we simply can't predict in this case?

Ja, lots of factors. The size and condition of line between the tank and BIRM filter. The volume of water drawn and the speed at which the valve opens. The amount of pex that can breathe and the pressure settings.

I would Tee off as close to the storage tank as possible so as to reduce line resistance coming from the tank and increase line resistance coming from the BIRM filter. Just keep in mind the possibility that a checkvalve may be desired and then also factor for where the expansion tank would go.

BTW, when I do the purge, I know I am getting flow reversal because I can hear the heat traps in my HWT rattle.

[JVance]

Everything will all be within a few feet of each other. The tee should fit within 12" of the pressure tank; the line to the BIRM filter just a couple of feet (due only to the height of the tank). And there is room to plumb an expansion tank between the BIRM filter and the inlet to the house with only a few feet of PEX. I'll plan to use the check valve and expansion tank.