15-vs-20-psi-steam-generators

15 vs 20 psi steam generators

Most generators, especially the cheaper ones, run at 15 psi. It saves the companies a lot of money because 20psi models require higher quality pressure release valves, better welding, and must be safe and have a higher rupture strength. I won't recommend any steam generator that is 20psi unless it is CSA certified. They do x-rays on the generators to make sure it is safe and won't break within the warranty period. A 15 psi model is much louder. You would think it would be quieter since it has lower pressure but the lower the pressure the more condensate that leaks out and the water and steam coming out at once makes water hammer. Also, most 20psi models have 3/4 or larger piping. I personally don't like the steam that comes out of 1/2 inch piping. Most commercial spas use 3/4 or 1 inch piping. Most homes have 1/2 inch so it's an extra expense to have a 3/4 inch. When companies try to sell you a steam generator that only works with 1/2 inches, it makes it easer to sell since it is what most people have already in their homes.

Warning: for those getting 20 psi steam generators that aren't CSA certified, you can expect fracturing of the weld joints and pressure relief valves. Most of the steam generator brands are not CSA certified and only UL or CE certified. I will not sell any steam generator brands if it is not CSA certified. Also, as far as drip pans go, I only get people calling me with leakage complaints so far on brands that are not CSA certified.

Notes: Higher psi makes the steam hotter as more pressure is built. Higher psi also makes the micron size of the steam lower so it stays in the air longer. (Boyle's Law...as pressure increases volume decreases.. something like that from what I remember physics in high school. I can't believe I would ever have a reason in my life to remember something like that)

Lower psi steam generators are louder (more condensate is released). Higher psi comes out stronger but less water is mixed in so it's quieter.

(With high psi I urge people to use at least a 3/4 inch pipe, never a 1/2 inch if you want it quiet and steam that's less wet)

NOTICE: YOU MUST HAVE AN AUTO FLUSH WITH 20 PSI SYSTEMS

Some steam generators have an autoflush built in and some brand you have to buy them separately. There are 2 types. Some just have a single autoflush cycle and other brands have an autoflush with an auto rinse following it. The dual flush system help so you don't have to change elements every few years. It can get very costly and it's a headache doing the maintenance. Even after 6 months, the limescale and calcium deposits on some cause the heating elements to slightly overheat and the steam room has an awful mineral smell. I personally don't like breathing in heavy metals in my steam from tap water, especially hard water.

Note: the cheaper brands that have incoloy heaters and not stainless or surgical steel heaters are get more corosive. Those that buy cheap generators end up spending more in the long run replacing everything (boiling tanks, heating elements, control panels that burn out). Also, the brands that typically don't have auto flushes built in usually have a low rupture strength. CSA approval probably doesn't exist. These companies do x-rays on the generator. Very few generators have CSA approvals.

Note: if you have hard water and don't have a good autoflush, you might have to change the heating elements every 6 months to a year or the heating elements in the steam generator will have too much deposits on them and it will burn out the generator.

Beware: if you are getting a high psi steam generator (not the 15 psi type) but the models that work at 20 psi, make sure they are hydrostatically tested. They are tested at higher pressure than designed for to test the strength of every part of the generator that could break under pressure. Also the best generators are tig welded. It is more expensive to get a hand done tig welded generator than an import from China.

If you are getting one of the open tank split dual tank generators (not pressurized steam), having it tig welded should help the steam generator last 30 years or so without being serviced. If it has a dual auto flush (not the single flush that most have) you shouldn't ever have to change the heating elements more than once every 10 years. They won't overheat by being covered in limescale but the filament instead the heater won't last forever. There are many generators on the market where you have to change the heating elements every 6 months (if using it with hard water) up to around 2 years if your water is not as hard.

Hydrostatic pressure testing

Hydrostatically tested for super high PSI giving dry steam

They use water at a higher pressure than it is designed for to test its strength

Please let me know on my steam generator questionnaire if you want a 15 or a 20 psi steam generator. 15 psi models are much cheaper up front but cost more in the long run and need more maintenance.

Note: There are 10 psi models. These are the really cheap ones you find coming from China. These put out about 50% more condensate than the 20 psi models. These make the most muggy steam that is so uncomfortable. totally opposite than the atmospheric steam generators that make the driest steam you might experience other than being in a sweat lodge.

Take my steam generator quiz here.

Warning: I must say this that if you upsize on a 20 psi generator, it does come out with more force. Be sure to use 3/4 inch pipes so it comes out with less force so it doesn't spray your feet and burn (see feet burn page.

High psi generator pros and cons (20 psi)

The higher the psi, the more limescale that builds up. The 20 psi models give steam with the least condensate and have driest steam but the only con is that you have to replace heating elements and boiling tanks more often to get this quality of steam.

Many people never change their heating elements and sooner or later you might have to set it 10 to 15 degrees higher to get the temperature you really want. This is because when limescale gets caked on the elements, many people find they have to turn up the temperature much higher than when the generator was brand new. Atmospheric generators rarely if ever need their elements replaced but these steam generators cost much more up front. These are a slow burn, single atmospheric type generator. See my page on atmospheric steam generators.

Getting just the right size steam generator

Low pressure steam generator complaints

Avoiding Steam Drippiness

Avoiding Cold spot and hot spots

Sizing Charts - I disagree with most of them

Avoiding Condensate and Wet Steam

NOISE COMPLAINTS