Hot Spring Spas of California has lost it's UL listing due to fires and not building spas to the ANSI UL standards for safety.

(Originally posted Dec 2003, and now they are doing the same thing.)


After the spas that caught fire with the 240 heaters on the tiny Lainge circulation pump, UL performed an investigation at my request and discovered that the design does not follow the UL safety instructions in regards to installing an electric heater in a portable spa.

(I talked directly with the engineers at UL and emailed them all the details. They were very responsive because UL is the number on standard in the USA for safety. Their reputation is on the line.  If a product catches fire "under their watch" it really looks bad on them.)

There are several design issues that contributed to the UL taking the UL listing away from Hot Spring spas.

If you  own a Hot Spring Spa with a UL sticker on it and it has a 240 heater, you need to contact the manufacturer for a recall and to have the spa built to UL standards or have them give you your money back.  The UL listing is voided by the design errors on the spas that can cause heater chamber overheat under normal operation.  And you cannot connect any electricity to it in most cities because it needs a valid UL listing, violating building standards.

  According to the ANSI UL safety rules the heater exit temperature cannot exceed 122 degrees F.  The normal operating temperatures of this "No-Fault" heater is much higher than that. Hot Spring puts a 151 deg temperature limit on many of their spas.  Put you hand in 151Deg F water and you will have burns and need to go see a medical doctor for treatment.

According to spa designers the small circulation pump used does not move the water fast enough through the heater to keep the water temperature from exceeding UL standards. Having it go through a venturi ozone injector reduces the flow even more. And they only have a 3/4 inch tubing used for "filtering and heating". When the filter clogs from use , dirt, and oils, the situation is worse, slowing down the flow even more.

If you own a 120 V version, you must never covert it to 240 volts, because of the possible scalding and fire hazards. And you need to keep the circulation filter clean at all times to avoid this fire hazard. 

For every year that Hot Spring spas has had a "listing" it has been "proud" to be "UL listed".  They were the first to get a UL listing in the 1980's. but this was for a 115V spa with a much smaller heater.  The design limits do not allow them to use a 240, 6,000 Watt heater on the same concepts.

After Watkins/ Hot Spring Spas, installed  240 V on that 120V heater, the spas started having safety issues and continual heater problems, because you cannot put 240 Volts and 6,000 Watts on a heater connected to any of the "Low Flow" circulation pumps. It is against the UL (Underwriters Labs) and ANSI (American National Standards Institute).

Finally UL listened to me after the spas caught fire. I have been telling the Watkins company directly about this for years, but they never listened to me. I complained to the FTC and the US CPSC to no avail, until the spas started catching on fire.  I got letters back from the "legal department" telling me in one sentence "There is nothing wrong with our spas."

Read these two pages from the Hot Spring Owner's Manual.

You will notice that before UL investigated Hot Spring the manual Page 60 shows a UL listing on the back page. After the UL investigation, they show ETL listing.  According to engineering standards ETL should never give them a "listing" either.

Unfortunately ETL was not advised by me of the ANSI and UL safety issues of Hot Spring. Hot Spring spas are not safe to own according to ANSI/UL standards for safety. That is a fact.



For those of you who are not familiar with UL or "Nationally Recognized Testing Laboratory".
UL , Underwriter's Laboratory is the one who makes these standards.  It is the UL/1563 that is used by all NRTL's. So, UL is the granddaddy of all testing labs who makes the standards. And because of anti-monopoly laws, they must share so that others, like ETL, can become a recognized testing lab.  In other words, UL is far superior, because it sets the standards for safety, compared to all the others in the USA.
The UL label is recognized in ever state, county and city in the USA, whereas the others may not be listed in the building codes of a particular city.  UL is the "Mac Daddy" of all testing labs in the USA and is the much preferred by all engineers to have on your products.

Here Again is my letter to the UL and US Government Consumer Product Safety Commission"

From: "Information Center" Date: Mon Jun 16, 2003 11:36:00 AM America/Denver To: Subject: Report a product to UL

Hello, Thank you for contacting the U.S. Consumer Product Safety Commission (CPSC). CPSC is an independent federal regulatory agency that protects the public from the unreasonable risk of injury or death from 15,000 products under our jurisdiction. CPSC would be interested in filing a report regarding your safety concerns in reference to the hot tub described below. Please contact our toll-free hotline at 1-800-638-2772, Monday - Friday, 8:30am to 5:00pm, Eastern Standard Time. Press 1 to begin and then press 300 to speak with a representative. However, to file a report with the Underwriters Laboratory Inc. (UL), you can contact the UL toll-free at 1-800-285-4476 or via web site www.ul.com. Please be advised that you may obtain CPSC publications, recalls and general safety related information via our web site at www.cpsc.gov. Click on the "Search" icon and type in your topic. You may also file an incident report via the web site mentioned above. man/myg

-----Original Message-----

From: James Arjuna <A HREF="mailto:[mailto:ja@spaspecialist.com]">[mailto:ja@spaspecialist.com]</A>

Sent: Saturday, June 14, 2003 8:02 PM

To: <A HREF="mailto:James.Abplanalp@us.ul.com">James.Abplanalp@us.ul.com</A>

Cc: Information Center; <A HREF="mailto:UCE@FTC.GOV">UCE@FTC.GOV</A>; <A HREF="mailto:info@nspi.org">info@nspi.org</A>

Subject: Report a product to UL

Dear UL;

I am a pool and spa professional and I work in the design of hot tubs and spas.

I am trying to understand how Watkins Products, Hot Spring Spas has a UL listing, since they are not a safe product according to the ANSI standards for building hot tubs and spas in the United States and your own UL standards.

They have several areas where the do not conform to the ANSI standard for safety and UL.

First of all I want to address the issue with the heater recall on the "No-Fault" heater used with a 6000 Watt heater.

There was a recall issued by the US Consumer Products Safety Commission back in Dec 2001.  (and now again in 2012 for the SAME problem.)

<A HREF="http://www.cpsc.gov/cpscpub/prerel/prhtml02/02068.html">http://www.cpsc.gov/cpscpub/prerel/prhtml02/02068.html</A>

When I first heard about the use of the 6000 watt heater with the tiny Lainge Circulation pump, I did some testing to see what the exit heat from the heater under various conditions would be, it averaged 130 degrees or more on the water at the heater exit according using that pump and the mazzie injection ozone system. Considering that the filters are blocking the suction on Watkins circulation pump, when the filter media is dirty the flow is even less, causing even higher temperatures inside the heater housing. The average consumer does not clean the filters as much as needed, so this engineering does not account for actual use by Hot Spring owners.

Basically a 6,000 watt heater CANNOT be used on a water pump that moves less than 18 to 20 Gallons per minute in order to keep the heater high limits below the ANSI standard of 122 degrees F, and to give any "grace" for filter media restrictions from dirt and oil.

It is because of improper matching of originally a 120 V 1500 watt heater then upping the power to 6,000 watts that this failure and the fires occurred. If the heater had been tested by you, UL then you would see the exit heat as being way to high for normal safety limits. That is why the recall was only on the 6,000 watt versions. This is basically a dangerous combination according to the ANSI standards for safety.

From The "American National Standards Institute, "American National Standard for Portable Spas ANSI/NSPI-6 1999



12.3.1 Water Temperature Regulating Controls: Water temperature regulating controls shall comply with ANSI/UL 1563 "Standard for Electric Hot Tubs, Spas and Associated Equipment". and UL 372 "Primary Safety Controls for Gas and Oil-Fired Appliances."

Owner/operator shall routinely check the in-spa water temperature to ensure that the temperature does not exceed 104 F. [40 C]. Any adjustment, if required, shall be performed in accordance with manufacturer's specifications.

12.3.2 Water Temperature Limiting Controls: Water temperature limiting controls shall comply with ANSI/UL 1563 "Standard for Electric Hot Tubs, Spas and Associated Equipment". The water temperature at the heater return outlet shall not exceed 122F [50C].


My commentary;

This seems pretty straight forward, except that the largest hot tub manufacture on earth has a thermal high limit switch calibrated much higher than this. The purpose of the high limit is to protect, the bathers from super hot water entering the spa vessel from the heater. If you have a 240 Volt, 6,000 Watt, heaters it is impossible for the water to exit the heater at less than 122 degrees with a tiny circulation pump. So, you cannot have a 240 volt 6,000 watt heater on many spas according to this safety standard. If the filter clogs up, the little child standing on the outlet of the heater in the floor of the spa will have scalded feet (the reason for the safety limit in the first place).

When that tiny circulation pump was first used it was on a 115 volt 1500 Watt heater, which is inadequate for cold climates. At 3 GPM they still had problems with the high limit at 121 degrees tripping. The 121 Degree "Hi-Limit Switch" was the standard because it keeps the limit below the specified 122 degrees in the ANSI Standard. As the other spas progressed and started using larger heater, this company (Watkins) was left in the dark ages with cold tubs. In order to compete, they started using the same tiny amount of water flow on a 6,000 Watt heater. Some of the early versions had a 151 degree F high limit on the heater. If you ever get a chance, and want to see how hot that is, stick your finger in 151 degree F water, and tell me if you could stand it?

<A HREF="http://www.cpsc.gov/cpscpub/pubs/5112.html">http://www.cpsc.gov/cpscpub/pubs/5112.html</A>

Why do we have the same "Recall" almost 10 years later for the SAME EXACT problem? 


According the the ANSI standard above, the rate of water turn over for a portable spa shall be the entire contents circulated in one hour to have adequate, minimal filtering.

The Hot Spring, Watkins products do not follow that standard either.

Under Article V of the ANSI/NSPI American National Standard for Portable spas also states:



5.1.1 The system shall be designed to turn over the entire spa water capacity at a minimum of once every hour.


If you do the math that means the a spa with 500 gallons must filter 12,000 gallons per day. In my testing a spa with 500 gallons use by four people daily needs about 30,000 gallons of filtering in order to clean up the water,, or you have to use lots of extra chemicals to help the filtering.

Do the math: A 7 GPM ( maximum) tiny circ pump in a 525 ( The Watkins, Hot Spring Grandee Model) gallon spa does not turn over the water once every hour.
7 Gallons per minute x 60 minutes = 420 Gallons per hour.
At 5 GPM it is worse. This is the condition with a partially dirty or clogged filter.
5 Gallons per minuted x 60 minutes = 300 Gallons per hour.  (This was fine on the 300 Gallon "Classic" Hot Spring Spa with 1500 watt heater element; the model all spas were designed from and where the sales pitch ("our spas filter all the water all the time". Which is, scientifically, a lie, because water filtering is a progressive reduction of particles filtering only a small quantity of the spas vessel at any one time. )

According to the manufacture the spa turns over the water from 5,200 gallons per day, not 12,600 gallons required by the bare minimums of the ANSI standard.

On page 14 of their advertising brochure it states that they turn over the water 10 to 15 times per day, instead of the ANSI required 24 times per day. That means the owners are having to deal with poor quality water, by using a lot more chemicals and water clarifiers, scum digesters, more powerful and dangerous "corona discharge" ozone generators and the like. It is not good to breath the ozone from a poor ozone system that allows the ozone to gas off above the water where the bathers can breath it. *(See quote from the ANSI standard below)

Considering that a spa with 500 gallons and four daily bathers has the same amount of debris per gallon as a 20,000 gallon swimming pool with 200 swimmers, due to the heat, sweat, and the amount of human skin per gallon of water, you can understand why I believe this is a health hazard.

In my own testing a 500 gallon spa needs to have about 19,000 to 24,000 gallons of water turn over per day to have clean water, because of the amount of body waste per gallon.

There have been several newspaper articles lately about people getting sick from indoor hot tubs. The doctors believe that the build up of bio-film in the spa spits out bacteria into the air and give the "hot tub lung" disease. I believe that part of the problem is inadequate filtering, that allows the scum to build up in the spa plumbing. Then when the spa jets are turned on they spew out bacteria into the air around and above the hot tub. In an indoor spa the bacteria is carried to the sleeping area by the house ventilation system. This is a serious problem that can be partially solved if the spa manufactures were to follow the ANSI minimums.

I don't think the ANSI minimums are safe according to my testing on spas regularly used by four or five people. Watkins doesn't even come close to those inadequate minimums.

Under Article VIII of the ANSI/NSPI American National Standard for Portable spas also states:



8.2.2 A minimum of two (2) suction outlets shall be provided for each pump and the suction outlet system, separated by a minimum of three feet (3) [91.44 cm] or located on two (2) planes; i.e., one (1) on the bottom and one (1) on the vertical wall, or two (2) separate vertical walls. These suction outlets shall be plumbed such that the water is drawn through them simultaneously through a common line to the pump.


If you examine the Hot Spring, Watkins products there is no second suction inlet on any of the spas. All of the water is passed through two filters and they are on the same plane, in the same filter housing. Also the size of the filters are not large enough each to fulfill the UL on having each suction inlet be able to take the full flow of the pump volume. The pumps on Hot Spring, Watkins are capable of 60 to 70 Gallons per minute GPM (according to their representatives) and the filters are capable of a maximum of 30 GPM each, according to the manufacture of the filter fiber and the largest filter housing manufacture in the US, Waterway plastics. Each of the suction "fittings" must be able to draw a minimum of 60 Gallons Per Minute, equivalent to the total draw of the pump attached.

My commentary:

This is about a simple as "apple pie". You can change the spices in the pie, but you can't leave out the "apples and the crust". You must, by these rules of safety, separate the suction inlets and have two on each jet pump. The fittings have to be ANSI/NSPI and UL safety suction fittings as well and each suction inlet must be rated for the full flow of the water pump.

Take a close look at a Hot Spring spa and tell my why you have put your UL sticker on it. It is not only against the UL standards, it is against the ANSI standards.


Most all of the problems relating to this company is due to the 100% no bypass filtering and the tiny circ pump, the two major selling points they use. These spas should be outlawed, until they conform to the ANSI and UL standards. Any spa that touts a 24 hour circulation pump, and a 6000 Watt heater, you better check to see what the circulation rate is and the heater exit temperature. The bare minimum for safety is 18 gallons per minute according to my testing. When you start with a flawed engineering, then try to build on it, it just gets worse. This is why I tell consumers to avoid all spas that use a tiny pump, less than 18 gallons per minute on a high Watt heater. That takes care of about 20 brands that I know of, including all the major ones from Southern California.

Because Hot Spring spas sells so many spas, other companies are following these dangerous concepts of inadequate filtering and super hot heater "high limits", including Sundance spas, Jacuzzi, Dimension One and many others.

They seem to think that placing similar devices on their spas will increase sales. In this way the sales people do not have to sell against the concepts of the tiny worthless filtering from a Lainge pump that moves 5 GPM past the mazzie injector.

This is a health and fire hazard (as already shown) and needs to be rectified, NOW!

I have written directly to Hot Springs about these issues, and they do not respond. They deny there is anything wrong with their spas.

You should take the UL listing of Hot Spring spas completely away, until they conform to the safety standards of the United States.

Thank you for taking the time to consider this very important issue.

* Quote from the ANSI standard on Ozone.

Page 31 Appendix D.


"Although the decomposition precludes the possibility of large amounts of ozone being present, ozone, like all chemicals capable of oxidation, is a hazardous substance, and ozone-generating equipment can produce dangerous levels of the gas. The United States Occupational Safety and Health Administration (OSHA) has standards for the exposure to ozone. Research indicates that there are no irreversible effects caused by accidental exposure to low non-lethal concentrations of ozone. As a general principle, however, breathing even low levels of ozone should be avoided at all times. Further information can be obtained from OSHA or the International Ozone Association, Pan American Group, 31 Strawberry Hill Avenue, Stamford, CT 06902".

The way that Watkins uses ozone does not conform to this either. When these reports were generated the CD(corona discharge) ozone generator was not in common use. The CD ozonator produces nearly 5 to 7 times the ozone output of the prior ozone generators. The only way to inject ozone safely is to have shut off on the unit while the bathers are present, or to use a 100% ozone saturation contact chamber, that Watkins does not use. Raw ozone is escaping the top of the vessel in fairly high concentrations.

I believe that an immediate recall be issued to Watkins to notify all of their existing customers about the safety issues in the Watkins, Hot Spring Products.

They Watkins proceed to repair and fix all of the existing spas that do not conform to the UL or the ANSI standards for clean water; for suction safety and heater high limit violations from the standard maximum of 122 degrees F. The spas should be tested and the heater out let temperatures tested to see if the outlet sends water higher than the safety maximum. The water flow for filtering needs to be raised to meet the minimums of the ANSI for 24 times a day of changeover and second suctions need to be placed on each pump on all the existing spas

James Arjuna

Havenmade Inc.

Broomfield, CO 80023

CC: US Department Consumer Products Safety Commission

CC: The US,. Federal Trade Commission

CC: National Pool and Spa Institute

Email: jim@havenmade.com