I think it's finally time to install a PRV, but I have questions

[Tubby]

Now I am worried about not having a pressure relief valve on my system. It's been that way for 40 years.

My pressure switch and tank are in the basement. There is no PRV, and no tank drain valve. There is not a drain in the basement floor. The rear of the basement is above ground, as the home sits on a slope. So, back there the concrete slab is roughly level with the outside.

The builders, in 1985, apparently thought it wasn't worthwhile to drill an outlet through the rear basement wall/foundation near the floor for the tank or PRV to be able to drain by gravity to the outside ground surface.

To correct this properly would (I think) require elevating the tank a bit, installing a PRV, and running its drainage hose (or PEX?) around and downward on the walls and then through a new hole in the outside (rear) wall or garage door corner. This would satisfy the normal rule that the drain has to be lower than the PRV.

As an alternative, I am considering draining a PRV into the existing laundry drainpipe nearby in the basement, which is a few feet high and open at the top where the washer hose hangs inside it. This would be bad for my septic system (flooding it more or less), but the pump would run dry in a few hours (it sits in a shallow spring), and the PRV would close.

In this configuration, the drainage hose would be running "uphill" from the PRV to the laundry drainpipe, which is supposedly against the rules; but, as I understand it, this just means I would have to properly drain the pressure relief hose after the emergency is over and the pump has been powered off at the breaker box.

Either way, I need to get a PRV installed or at least replace the pressure switch, right? The switch is 15 years old.

BTW, the old pressure switch might have lasted 25 years. It literally fell apart when I was having it inspected before buying the place.

Also BTW, I'm aware that a Cycle Sensor would turn off the pump after it runs dry. But it's not clear to me how, or whether, a CSV would possibly mitigate the situation (when the cutoff switch fails).

 

[Reach4]

This would satisfy the normal rule that the drain has to be lower than the PRV.

That would be the case for a water heater, but I don't know that that is the case for a pressure relief valve for a well.

You are required to have a T&P relief valve for a water heater.

 

[Sponsor]

 

[Valveman]

The CSV doesn't take the place of a pressure relief valve, which is needed if the pressure switch fails to shut off the pump. Not really important that a prv drain at a downward angle. Shouldn't ever be used anyway. But a prv can be installed anywhere in the system. It can even be outside on a tee with a hydrant or hose bibb. It is important that you can see the water coming out of the prv, as that is your high pressure alarm and something needs to be fixed.

If a PRV pops off and runs the well dry, a Cycle Sensor will see the amps of the pump/motor drop to about half and shuts the pump off before there is any damage.

 

[Tubby]

edit: looks like AI is referring to the wrong codes reqs.

In any case, a new pressure switch should help me sleep easier. I presume it's time to replace this 15-year-old one, but I hope they still make them to last (unlike most other products).

 

[Reach4]

I am skeptical of that "supposedly the code requirements".

That sounds an awfully lot like it misapplied a code for a WH T&P. Not saying that your county could not have adopted such text, but it seems unlikely. Do they even require a require relief valve for a well pump? Also note that PRV usually stands for pressure reducing valve.

Let's say you are a real worrier, and want to do what you can. You could have the require relief valve output piped to a tee on a high point. You could mount a vacuum breaker atop the tee. You could run the other port of the tee at a downward slope to daylight. The slope to where you leave the heated space should be enough to cause the minimum vacuum required to open the require relief valve.

Another simpler way would be to use a large-enough pipe sloping down to where you leave the heated space that a vacuum will not form. These worrier ideas are overkill IMO.

Another possibility is to tee off to an exit point that could freeze, rise further, and then feed to your laundry tub/septic. The water goes outside unless it gets blocked.

Also note that flowing water is not going to freeze anyway. I expect that even a well sucked dry will keep some minimal flow of water+air that so that the pipe would not freeze.

 

[Tubby]

I am skeptical of that "supposedly the code requirements".

That sounds an awfully lot like it misapplied a code for a WH T&P. Not saying that your county could not have adopted such text, but it seems unlikely. Do they even require a require relief valve for a well pump? Also note that PRV usually stands for pressure reducing valve.

Let's say you are a real worrier, and want to do what you can. You could have the require relief valve output piped to a tee on a high point. You could mount a vacuum breaker atop the tee. You could run the other port of the tee at a downward slope to daylight. The slope to where you leave the heated space should be enough to cause the minimum vacuum required to open the require relief valve.

Another simpler way would be to use a large-enough pipe sloping down to where you leave the heated space that a vacuum will not form. These worrier ideas are overkill IMO.

Another possibility is to tee off to an exit point that could freeze, rise further, and then feed to your laundry tub/septic. The water goes outside unless it gets blocked.

Also note that flowing water is not going to freeze anyway. I expect that even a well sucked dry will keep some minimal flow of water+air that so that the pipe would not freeze.

Right, it turns out that the idiot Grok AI was referring to boiler/heater T&P codes. So now I'm going with the idea that I just need to put a relief valve where my outside spigot is. At the moment I have nothing to prevent a catastrophe if that pressure cutoff switch fails. It's probably unlikely, but Murphy must be respected.

 

[Fitter30]

Right, it turns out that the idiot Grok AI was referring to boiler/heater T&P codes. So now I'm going with the idea that I just need to put a relief valve where my outside spigot is. At the moment I have nothing to prevent a catastrophe if that pressure cutoff switch fails. It's probably unlikely, but Murphy must be respected.

Water heater t&p has to be installed in the heater at the factory outlet. T & P stands for temperature and pressure. 210°f and or 150 lbs. What kills any pressure switch is constant fast cycling. Otherwise the last for years. Hole through the foundation would need a hammer drill with 1.250 or 1.125 bit x 18"
Could rent one. Need gloves hearing protection and safety glasses. Polyurethane caulk to seal the pipe to hole.

 

[Tubby]

Update: I was talking on the phone to a rep for the leading driller in this area, and he remarked that my pump probably can't generate enough pressure to burst my tank (Wellsaver, bladder type). Not sure I'm willing to take his word for it. My pump is:

SHUR-DRI
SD-A202-02
Submersible Well Pump
3/4HP, 10GPM 2 WIRE
230V 60Hz 1PH
Code: 001J09H
Assembled in USA

 

[Valveman]

Update: I was talking on the phone to a rep for the leading driller in this area, and he remarked that my pump probably can't generate enough pressure to burst my tank (Wellsaver, bladder type). Not sure I'm willing to take his word for it. My pump is:

SHUR-DRI
SD-A202-02
Submersible Well Pump
3/4HP, 10GPM 2 WIRE
230V 60Hz 1PH
Code: 001J09H
Assembled in USA

Wow! It is not pressure that "burst" a tank bladder/diaphragm but rather the flexing up and down from the pump cycling on and off. A 3/4HP, 10 GPM can only build about 120-130 PSI, but that is a moot point.

 

[Tubby]

Wow! It is not pressure that "burst" a tank bladder/diaphragm but rather the flexing up and down from the pump cycling on and off. A 3/4HP, 10 GPM can only build about 120-130 PSI, but that is a moot point.

It is the outright failure of the pressure cutoff switch that concerns me, which I suppose could break the tank or anything downstream of it. An exploding tank is the scare story I most hear about.

I am leaning to what you said about putting a relief valve further away, on an outside hose bibb for example. Or I could put a valve off the same copper pipe right inside the garage and run a hose through a hole to the outside (wouldn't want the the valve to be exposed to freezing).

 

[Fitter30]

Can't find anyone selling your pump or expansion tank. Was looking for a pump curve and for thr ex tank working pressure. Most are 100-150 lb. Should be in the install manual. My 1 hp well pump 270' at well the shut off pressure is 97 lbs. That is the max pressure the pumps going to put out. Can bypass the pressure switch with all valves closed see how high the pressure gets only has to run a few seconds. Tanks have a working pressure and bursting pressure. Like a water heater 150 working 300 lbs bursting.

 

[Valveman]

It is the outright failure of the pressure cutoff switch that concerns me, which I suppose could break the tank or anything downstream of it. An exploding tank is the scare story I most hear about.

I am leaning to what you said about putting a relief valve further away, on an outside hose bibb for example. Or I could put a valve off the same copper pipe right inside the garage and run a hose through a hole to the outside (wouldn't want the the valve to be exposed to freezing).

You don't have to worry about the tank exploding. As Fitter said the burst pressure of most tanks is 300+ PSI. If the pressure switch fails to shut off the pump, the pump will melt down long before there is any damage from high pressure. A pressure relief on a well system is not there to keep the tank from exploding, it is there to keep the pump from melting down. If a pressure switch fails the pressure relief leaks enough water to keep the pump cool. That should be your concern.

Having said that I will say this again. Pressure switches, tank diaphragms, check valves, capacitors, and most especially the pump/motor itself are all damaged and destroyed from the pump cycling on and off too much. Eliminate pump cycling and neither the pressure switch nor anything else will fail.

 

[Valveman]

Now the old galvanized tanks would explode. The bottom is concave, and goes convex when there is too much pressure, blowing the bottom off the tank and sending it up like a rocket. I have seen them go through the roof taking most of the plumbing with it. This is a picture of one that exploded in a cinder block well house. Notice the tank floating in the lake top center of the picture.

 

[FredG]

Wow, that is a lot of damage. How often of an occurrence was a tank lift-off? Was it relatively rare? I’ve only heard of them launching on this website.

 

[Fitter30]

Tanks that contain air or water have a bursting rating not a explosion rating along with a working pressure. Water heaters explode for one reason. They run out of water the gas burner stays on heating the tank red hot. Water enters the tank flashes to steam. Steam expands 1600 times more than water. There isn't a relief valve large to relieve all that pressure instantly tank explodes. Electric water heater with no water in tank the elements burn up with in a minute or two and quit heating.

 

[Valveman]

Wow, that is a lot of damage. How often of an occurrence was a tank lift-off? Was it relatively rare? I’ve only heard of them launching on this website.

In almost 60 years of working on pump systems I don't need all the fingers on one hand to count the number of times I have seen or heard of that happening. It is rare. Galvanized tanks are seldom used these days, and most people have a pressure relief valve.