please vet this plumbing flow

Dec 30, 2013
40
SF, CA, USA
here's what i think i'm doing; what have i missed?

tub >> drain tee valve >> fill tee >> pump >> thermo/mano meters >> filter
>> heater >> thermo/mano meters >> chemical injection tee >> flow
switch >> water meter >> check valve >> aeration tee >> tub

in case it matters, the tub is _above_ the rest of the parts. to lock the system for maintenance, i will rely on the check valve and the neutral position of the drain tee valve. fill (at mains pressure) will use both lines, reversing flow on one of them.

thanks!
 
Are you plumbing it into the house? That's a double secret probation no no.

Drains suction water to a pump which forces it through a Filter then a heater and maybe a chlorine injector then back to the tub through returns or jets.

Do you have a plan or equipment selected?

You fill it with a hose.

Gauges for what?
 
thanks for responding.

Are you plumbing it into the house? That's a double secret probation no no.

well put. there's both a check valve and a ball valve in the fill line, and the ball valve will only be opened while filling is happening. mains pressure is always much higher than the plumbing head. would you use more advanced backflow prevention?

Drains suction water to a pump which forces it through a Filter then a heater and maybe a chlorine injector then back to the tub through returns or jets.

Do you have a plan or equipment selected?

yes, i think what you wrote is congruent with the plan i described above. i have a laing e5 plastic pump, hayward micro star filter, raypak gemini 3 heater (modded with a different flow switch), and a homemade chlorine injector bottle. the wooden tub (probably cedar) will be plumbed with flex PVC over to the equipment station.

Gauges for what?

who doesn't love 4" analog gauges? i will be able to see the pressure differential across the filter, how much hotter the water coming out of the heater is, the rate of water flow and electric current being used.... the holy grail would be a pH meter and i have been working on an old rugged one to see if i can get it working. this is all optional, just my own interest in watching and tracking the state of things.
 
Absolutely use a purpose build backflow preventer.
Mains pressure is fine while it is there.
If the city water has a problem (pressure loss or even suction) you must prevent any water being drawn back into the city system.
That is the reason sprinkler systems have them.
 
i really appreciate hearing from you folks that what i have planned doesn't seem wise. does anyone know what the code actually calls for here - DCVA, PVB, RPZ, APB, RPBP, etc.?

i know mostly people like the air gap (i.e. a hose), but i don't want my tub to work that way if i can get around it. the check valve is the cheapest of the rest of the mechanical BP devices, followed of course by two check valves in a row. another option might be to plumb in an air gap (i.e. a spigot and cup) located above the water line, ten feet above the equipment. it's more practical than a hydrostatic loop! thanks everyone for your input.
 
Here our nearby city is working towards back flow prevention on all meters, the first phase was requiring it on all houses with pools (even above ground pools filled by hoses as the hose may be left in the water), and on all new construction. I don't know their timeline for retrofitting older houses though, although I think they have some type of 5 or 10 year plan to be compliant with new federal regulations, they have also added locking caps to all the corner fire hydrants (looks like a red coffee can with a padlock on the top of the hydrants), I don't know if that was related or not as there has never been much issue with unauthorized people opening them around here. I suspect they are going to tie the change over in with change of ownership otherwise I suspect the masses here would vote everyone out of office as the backflow devices cost about $250.
 
I would go down to 1660 Mission to the SF DBI Permit Services desk. As I recall there is a building guy on duty at the desk on the first floor to answer questions. This is San Francisco so the normal rules don't apply. Its toppsy turvy land. Let me repeat that -- in San Francisco what you think the code requires and what SF requires may be very different.

Explain what you want to do and ask your questions. You need a permit. Probably a residential pool permit. But they may see things differently.

They can best advise you on what SF requires. If you PM me I can give you a few phone numbers and names. But my clients have not pulled a permit in SF in at least 2 years so I am not current as to whats happening at DBI.

In California fill lines are never in my experience connected directly to the recirculating system of the pool. They are run to the pool directly with a listed backflow preventer and usually an auto fill. You could omit the autofill.
 
well, here is the answer from the city documentation:

in-wall fill lines with no downstream valving -> APB
automatic fill lines with downstream valving -> RPBP
fill lines connected to a filtration suction or return line or any pressurized line -> RPBP

thanks folks. i'm going to figure out where to put an air gap instead of buying an RPBP. then i can still fill with hot water (my flash heater has about six times the capacity of the raypak unit) without having to handle the hose.
 

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heh heh. it's always good to know what the law really calls for. the way i read this, plug-in electric tubs are illegal in SF too: they lack automatic chlorinators, RPBP, handrails, depth markings, and so on, never mind the decking around 50% of their perimeter within an enclosure which doesn't touch any property lines. the law appears to be drawn up for public or hotel facilities. gwegan, is sacramento really any less strict?
 
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