Constant pressure pump, 20 gal tank, low pressure from faucets with 2 or more faucets open

[Twowaxhack]

On the cold side it would be good to eliminate any fittings you can and increase the main runs to 1” pex.

The hot side comes with a trade off for upsizing. There’s a longer purge time in order to get hot water to your faucet. If you have a circulating hot water system then it’s not an issue but otherwise it can be. So be aware of that on the if you upsize the main hot run.

I can’t stress enough to eliminate all unnecessary fittings on both hot and cold side.

We’re not trying to win the plumber of the year with straight pipe runs……how good it looks doesn’t mean jack of it doesn’t operate well.

Every fitting reduces pressure and restricts volume. Period.

I’ll help you anyway I can.

 

[Twowaxhack]

Keep in mind that when you take a shower or a bath with 120 degree hot water settings that MOST of your flow will be hot water to obtain your 105-110 degree mixed water.

At my house, no small kids and no handicap people and I have pressure balanced shower valves…….I run my hot water at 140 degrees. This gets me closer to a 50-60% ratio of cold to hot water to achieve my 105-110 degree mixed shower water. This keeps my flow up because I’m drawing from both hot and cold near equal.

You can also throttle down the washing machine valves. The machine will fill slower but your pressure/volume will not take such a hit while the machine is filling. Same with toilets, you can restrict their flow a little.

They’ll fill up a little slower but it won’t tax the system much. Every little bit can help when you’re trying to achieve top flow and volume.

 

[Mrpalazzolo]

Keep in mind that when you take a shower or a bath with 120 degree hot water settings that MOST of your flow will be hot water to obtain your 105-110 degree mixed water.

At my house, no small kids and no handicap people and I have pressure balanced shower valves…….I run my hot water at 140 degrees. This gets me closer to a 50-60% ratio of cold to hot water to achieve my 105-110 degree mixed shower water. This keeps my flow up because I’m drawing from both hot and cold near equal.

You can also throttle down the washing machine valves. The machine will fill slower but your pressure/volume will not take such a hit while the machine is filling. Same with toilets, you can restrict their flow a little.

They’ll fill up a little slower but it won’t tax the system much. Every little bit can help when you’re trying to achieve top flow and volume.

We have our tankless 199,000 BTU natural gas water heater set at 120 degrees. It does have a small recirculation pump in it. I thought about increasing the temp up, however, I have read that increasing the tank temp may actually decrease the water flow (gpm) since the delta temperature difference has to be compensated for. The larger the delta, the lower your flow rate, so what I have read.

I like the idea of throttling down the washing machine valves.

I think at this point, we want to have a competent plumber come in and assess what we have, put some gauges in and measure flow rates, and see where we can make improvements, if any.

 

[Twowaxhack]

We have our tankless 199,000 BTU natural gas water heater set at 120 degrees. It does have a small recirculation pump in it. I thought about increasing the temp up, however, I have read that increasing the tank temp may actually decrease the water flow (gpm) since the delta temperature difference has to be compensated for. The larger the delta, the lower your flow rate, so what I have read.

I like the idea of throttling down the washing machine valves.

I think at this point, we want to have a competent plumber come in and assess what we have, put some gauges in and measure flow rates, and see where we can make improvements, if any.

If your water heater can’t produce the demand at the set temp, some heaters will throttle flow until temp is maintained. You shouldn’t have that problem with just two normal showers running 3-4 gpm. But about 70% or more will be hot water. Your incoming cold water temp plays a part in that.

Don’t circulate water hotter than 140.

But with circulating hot water, purge time isn’t an issue. If you want max pressure/volume increase the hot piping main runs to 1” pex.

I’m making these suggestions with your past posts in mind and what I believe you expect out of your system.

Personally I like hot water. 130-140 degrees for multiple reasons. I could talk about why for an hour. I like my shower water to be as close to a ratio of 50% hot and cold without going over 140 degrees. Over 140 degrees and you bring on other problems like mineral fall out and increased corrosion.

 

[Twowaxhack]

Kick the pressure up to 80 psi. See what happens.

Check the tankless water heaters inlet filter.

How far is your pump away from your home ? Uphill ? Downhill ? Level ?

 

[Valveman]

The insert fittings in 3/4 pex make it more like 1/2" pipe. That can reduce the flow and pressure considerably. But I would still try bypassing the softener before anything else. If it is a restriction problem turning up the pump pressure to 80 PSI will help squirt more water through the small fittings.

I throttle the valve to my washing machine because otherwise with 60 PSI constant it fills so fast the solenoid valve causes water hammer when it shuts off.

As long as it is working properly the variable speed pump should compensate for any increase in flow and keep the pressure the same. A Cycle Stop Valve can do the same thing without varying the pump speed or the additional cost that goes with. A 30 gallon pressure tank only holds about 7 gallons of water, but you do not get that water from the tank unless the pressure drops 20 PSI. If the constant pressure controller stays at the same constant pressure ALL THE TIME, the tank is not even being used no matter what size it is.