Boiler Gauge Readings

I will give this a try.

Physics says that water can not make steam, at sea level pressure under 212 degrees F.

It is also why steam pipes and automobile systems are under pressure, you can hold more heat, when water is under pressure and not have it boil. Pressure cookers cook food faster for the same reason.

The only way to make steam, from water, at 180 F, is to do it under partial vacuum.

To get water to boil at 180 F, you need to reduce the air pressure to about 7.5 psi.

7.5 psi is a column of water about 15' tall.

If a boiler tank, had a 15' tall pipe, filled with water, and caught between a drain trap and the return to the boiler, it would make steam at 180 F.

I have a physics background, and I am not a stationary engineer, well not a train engineer either, to be honest.

Hopefully someone who has actually worked on a boiler system can take this and run with it.

• Note, never pay someone to work on a boiler that thinks the temperature of the water should be below the boiling point of water.

You are better off hiring a competent plumber to work on a storage water heater. You get the same result with fewer parts, faster, and for less money.

The boiler should not significantly affect your water pressure. Tankless boilers do put water through a somewhat more twisty path than a traditional water heater, but if the unit is properly sized for your installation and properly piped, the impact of this on water pressure should not be noticeable. If your hot water pressure, ideally tested from multiple faucets within your home, really is lower than your cold water pressure, your system may be incorrectly installed or require maintenance.

If your boiler has a pressure reducing valve, it is most likely the valve that regulates the pressure of cold water supply into your hydronic heating system. A picture and/or model number would help confirm.

Though you haven't said it explicitly, I'm guessing you are getting less water pressure from your shower than you'd like. If you aren't seeing lower hot water pressure at other fixtures, then it's also possible you have an issue with the mixing valve in your shower faucet. These can clog due to mineral buildup or perform incorrectly due to wear. You may also have a shower head that doesn't let much water through.