New Rheem Rtex 18 on my 32 year old low pressure 1gpm max on my rural well water recommendations?

[Adam Burdette]

Hey guys I am new to Tankless Water Heaters, I just ordered a a electric tankless RTEX 18 for my house. It’s sn old single wide mobile home I think this one will be able to do what I need it to with ease. So I have never owned a house before this one I bought it 10 years ago it was put here in 1991 it had a 300 foot well with a new well pump that’s at the very bottom of the well I replaced it 2 years ago. Past that everything else is what was here when I moved in. I get extremely low pressure despite having bought a 3/4hp pump. The pressure is not amazing but pretty good on the manifold the switch and gauge are on that is attached to the tank. But after 1-200ft in a water hose outside it has pressure that wouldn’t work for a slip and slide last year, also if I leave the water hose on for awhile the breaker will just trip but it does that before and after the filter. It doesn’t cut off inside the house at all from the breaker tripping when we use the water for 15 mins or so. I would estimate I get 1gpm maybe inside the house at any water outlet cold or hot. The pipe from the pump to the expansion is perfect no leaks anywhere. The expansion tank is at 28psi and the pressure cut in is 30 and the cut out is 50 I’ve also used a 40 / 60 . The piping from the expansion tank to the filter is 1.5 feet and from the filter to the water heater tank is 1 foot more but the length of the pipe is 10-12 feet max. The hot and cold for the washer is less than a foot from the water heater. The washer is about 1” to the side & gets the same pressure as every other thing even less making my washer have 4c low water pressure errors all day. It’s hard to gauge because it’s 1 single thick jet of water vs aerated or water from the shower head pattern that’s slower but seems to be more. I’ll have to buy a pressure gauge I can use anywhere on my system today I’m about an hour. But more information the pressure is the same if I take the water filter out and use it’s housing without a filter. It’s a garbage filter I bought a new one with 3 filters in a row with my tankless. I also bought a new spin down and a uv-c sanitizer. Then it will go straight ti the tankless that’s about 5 feet above it. The expansion tank is outside under my house. In a little area that’s kept from freezing in winter but a light bulb and that’s all. It had never failed me as long as the bulb didn’t go out but I made a thing to be able to know imminently if it happens now. The entire houses piping for hat and cold are the same grey 1/2” pex.

on my house is have

1 washer
Master bathroom with toilet sink and bathtub/shower
All 4 of these within 10 feet of the water heater.

kitchen sink and dishwasher about 20-25 from the water heater

and 1 more toilet sink and shower/bathtub across the house and that’s about 50-55’ away from the water heater.

my washer is new Samsung about 2 years old the bathroom has brand new vanity, toilet and bathtub/shower has new faucet & a custom 18” rain shower head in the middle from the roof. and 4 wall sprayers from the front and a hand held sprayer on it you can adjust what you want to have on at any time and how much pressure it gets.

‘the pressure was never anything great at all but it was better for sure. It is so low pressure for us here the first time I had a shower somewhere else with city water in about 7 years of using mine I almost died and it hurt it and I also almost drowned. Anyways I’ve wanted a tankless since I learned about them 10 or so years ago. And it’ll be here Tuesday and I am going to buy everything else from Lowe’s in about 45 mins and whatever I forget today I’ll pick up tomorrow on my way home. What do you guys think i should do.
Also I know the ppm filtration makes the pressure horrid. But the filter I’ve had for 5 years was 16$ Haha. Also we have super soft water here no softener needed. I live in Rockingham County North Carolina if you want to check out all of that stuff. If you would like me to find my personal wells data that I found from ArcGis I will grab whatever you can use. I am also going to test the water and find out how to take care of it. Never done anything to it except filter it. Yeah i didn’t know you could do anything I’m not even sure how it works or what you treat the well with and how much. So what do you guys think. Besides that i suck and this is my first house and I learned everything on my own and have daily, weekly, monthly, quarterly and annually also seasonal checklists I do to keep up with everything. I never even knew anything else except that well water was in the ground and there was a rock outside with the well under it. Everything is perfect now but always had low pressure. I have the time, money and can do electrical & Plumbing I will have it run at 240v with 2 of 40 amp 2 pole breakers. have wanted to fix that and get tankless since I moved here.

 

[Bannerman]

Hard to tell from your description if you have a well or pump issue, or whether there is a flow restriction after the well pressure tank. This needs to be addressed before you will have sufficient water to meet your needs. Once there is sufficient water, you can then utilize whatever tankless water heater you wish.

With 30/50 psi well pump pressure switch settings, assuming the pump has sufficient head pressure for the depth of the water within the well + 50 psi, the water system pressure should remain between 30-50 psi even while water is flowing to faucets or a garden hose. If the pump is not delivering sufficient water, you may want to describe your water supply issues within the Well and Pump forum as many of those participants specialize in well issues.

Although you said the well is 300' deep and the 2-year old submersible well pump is 3/4 HP, you didn't state the static depth of the water in the well. If for instance the top of the water is 50' or 100' below the top of the well (100' static), the pump will only need to lift water 50 or 100' + whatever amount the water further drops when the pump is running, not 300' even as the pump was placed at the bottom of the well. If you know the brand and model of submersible pump, that would be also useful.

Is the pump actually able to fill the Pressure Tank so the pressure increases to 50 psi for the pressure switch to shut off the well pump? You didn't mention the size of Pressure Tank installed on your system.

 

[Sponsor]

 

[Reach4]

The pipe from the pump to the expansion is perfect no leaks anywhere. The expansion tank is at 28psi and the pressure cut in is 30 and the cut out is 50 I’ve also used a 40 / 60 .

You have a pressure gauge. During your "low pressure" times, what does the pressure gauge say?

What you describe may be because the water level in the well drops to more than 25 ft lower than the pump.

 

[Bannerman]

Sounds as though the pressure and flow rate is consistently low. The pump is also located at the bottom of the 300' well.

 

[Sarg]

Just a couple observations ( I also have a mobile home ).
Your "Grey Pex" is more than likely Polybutylene ... also called Poly-B ........ totally different than Pex.
Sharkbite does make conversion fittings to join the poly B and Pex. They no longer make the Poly-B but you can still obtain Qest compression fittings for it. If and when you start having leaks or want to modify stuff converting to Pex is the best option.
Also ...... make sure you can rewire to the appropriate size for tankless unit. ( 8 ga. ? )
And just another tip ... you can obtain digital thermometers with remotes so you can monitor the temperature at your pressure tank. Amazon sells them with 1,2 0r more remotes.

 

[Adam Burdette]

Hard to tell from your description if you have a well or pump issue, or whether there is a flow restriction after the well pressure tank. This needs to be addressed before you will have sufficient water to meet your needs. Once there is sufficient water, you can then utilize whatever tankless water heater you wish.

With 30/50 psi well pump pressure switch settings, assuming the pump has sufficient head pressure for the depth of the water within the well + 50 psi, the water system pressure should remain between 30-50 psi even while water is flowing to faucets or a garden hose. If the pump is not delivering sufficient water, you may want to describe your water supply issues within the Well and Pump forum as many of those participants specialize in well issues.

Although you said the well is 300' deep and the 2-year old submersible well pump is 3/4 HP, you didn't state the static depth of the water in the well. If for instance the top of the water is 50' or 100' below the top of the well (100' static), the pump will only need to lift water 50 or 100' + whatever amount the water further drops when the pump is running, not 300' even as the pump was placed at the bottom of the well. If you know the brand and model of submersible pump, that would be also useful.

Is the pump actually able to fill the Pressure Tank so the pressure increases to 50 psi for the pressure switch to shut off the well pump? You didn't mention the size of Pressure Tank installed on your system.

The metal badge on the side of the tube says 300’ from the surface to the submersible pump i hate it very much as it is heavy and you can’t let it go period. I had someone show me the truck with some vice grips that were curved and held the pipe for us to take a break. He was my wife’s friends husband he dug wells and everything but It was a favor and took us hours to get it and put the new one down and had to pull it up twice I didn’t ask about the pressure and this was in 2013- 14 and im old and out of shape. It’s an even every time I’ve had to bring it up the well depth and its 300’ of rope and the black pipe is also 300’ I had to actually cut 6 or so feet off because there was sediment in my filter and it had gotten into my water heater snd my washer, toilets and bathroom sinks would barely work and the washer would take almost 30 minutes to fill every time, let me get more information about the actual well and the water when I get home snd I will post that all for you to be able to get a better idea of what I’ve got going on here. I can put this on the well pump is fine, or can I cross post this? I’m happy I’m getting help from people.
The psi when it turns off is 50-53 and it kicks in at 30 minimum 27 and pushes it easily back up. I had a proble, where the tank didn’t have the 28psi of air in it and the pump was constantly cycling, on off every 5-10 seconds when I was showering. It was after a tornado here and I had no idea about it even having air pressure or what is was supposed to be and when to put air in it but it stays at 30psi and keeps the 28psi always of air, but when it dies it just hits 30 the breaker trios and it just runs out until 0 whatever pressure is still left then I flip the breaker and pull the lever and it will take over after maxima 2-3 seconds and refuel tk 50psi, I know the psi needs to be like 15 or so,etching for the switch to go on auto and if not it will just stop when you don’t have the gold lever held half way up. When I doesn’t have right around the 30PSI ever is when the breaker has tripped. But I’ll get the info on the well itself and let you know

 

[Reach4]

The metal badge on the side of the tube the well goes down has 300lbs as the well depth and its 300’ of rope and the black pipe is also 300’ I had to actually cut 6 or so feet off because there was sediment in my filter and it had gotten into my water heater snd my washer, toilets and bathroom sinks would barely work and the washer would take almost 30 minutes to fill every time, let me get more information about the actual well and the water when I get home snd I will post that all for you to be able to get a better idea of what I’ve got going on here. I can put this on the well pump is fine, or can I cross post this? I’m happy I’m getting help from people.
The psi when it turns off is 50-53 and it kicks in at 30 minimum 27 and pushes it easily back up. I had a problem, where the tank didn’t have the 28psi of air in it and the pump was constantly cycling, on off every 5-10 seconds when I was showering.

So you have a submersible pump.

Your pressure tank has probably failed. It happens. That doesn't mean that is your only problem, but your quick cycling while the pressure stays above 27 pretty much identifies the problem. What is the make and model of your pressure tank?

Air precharge of a pressure tank is always measured, or set, when the water pressure is zero. When the water pressure is zero, the tank should be empty of water.

 

[Bannerman]

It sounds as though the well pump is delivering sufficient water and pressure while it is actually operating. Perhaps the double pole breaker and wiring for the pump is not sufficient for a 3/4 HP pump. When the pressure is lower, the amount of water the pump is moving will be greater so the load on the pump motor will be greater which will cause it to consume more power which likely is exceeding the breaker capacity, causing the breaker to trip when the system pressure is low.

Not clear on what you are referring to with taking 2-3 seconds when the pump is reactivated. The pressure tank should be large enough so the pump will need to run for 60-120 seconds to increase the pressure from 30 psi to 50 psi while no water is used. That 60-120 seconds will be the minimum pump run time. If the pump is requiring less than 60 seconds to refill the tank, the tank is too small. Pumps are designed to run continuously so it is short, frequent On/Off cycles that are damaging and will reduce the lifespan of the pump, pressure tank and pressure switch.

Your pressure switch is equipped with a low pressure cut-off which is why you are needing to hold the lever until the pump raises the pressure to above 30 psi. Perhaps the 2-3 seconds you refer to is the time you must continue to hold the low pressure lever before you can release it? The low pressure switch is not necessary as many well systems do not use a low pressure cut-off when there is no risk of the well running short of water. When there is a well recovery issue, there are methods to reduce the pump delivery rate to match well recovery and/or shut-off the pump if there is insufficient water in the well.

 

[Fitter30]

If you have electric heat hope you have 200 amp panel 75amps heater uses. Heres a temperature rise/flow rate for the heater . 1 gpm-82*, 1.5 gpm-62*, 2 gpm-49*, 2.5 gpm-41*, 3 gpm-31*, 4 gpm-25* if you have 50* well water at.1.5 gpm 102* water. Garden hose pressure drop 200', 1/2" - 18 lbs, 3/4" - 8 lbs open end, every coupling add 5%. Need to cut in a valve to measure pressure before all the filters ( is there a hose bib before filters). Brand of housing, pipe size, filter and micron. Water flow needs to straighten out first standard water heaters are very forgiving.