Heater Tutor


What is a "low flow" heater? 

Industry in general use 3 rating of heaters and a variety of sizes and styles. Hot Tubs built after 2002 used mostly 5.5kw heaters but in several styles.

Simply stated, the heater is an element that when electrical current applies to it, it resists the current and doing so creates heat. Because the element resides in the spa water you can destroy an element in less than a year or with water care, extend the life to over 5 years. The average is 3-5 years.

Since the element is in the water, it's the #1 cause of the gfci popping. You must replace to correct. Sometimes you see corroding heater posts, sometimes on the element itself, and many times the "short" is hard to see. But is short what is happening is electrical current is leaking from the heater element to the water and the gfci is sensing it and shutting off the spa. That is GOOD. Means you will not be shocked or electrocuted.

The ratings of the heater is designed to match the current you supply the spa with the heater current draw. A 110-120vac spa has either a 1.5kw heater (heats 1-2 degrees per hour) or a 4.0kw heater (heats 2-3 degrees per hour) or on some spas a 5.5kw that heats about 3 degrees per hour.

The most common spa is designed to operate on 220-240vac. These heaters are 5.5 kw heaters which is the industry standard. You should expect about 5 degrees per hour.

Most placed their heater in a steel tube below the control box, behind the control box, and on a few models, to the left of the control box. With advice from us that we offer upon request after you order, we can walk you through the replacement.

The "J" series used several styles. Most common is the "U" loop heater with a small circ pump. Some models have a horizontal heater like the older JWB models did. Newer models use a free standing horizontal heater with a larger circulation pump.

Why did it last such a short time?   This is a common question so I'll cover it. The element is designed to be in balanced, quality spa water. I see heaters lasting 7-8 years. That tells me the owner takes care of their water and it's from a good source. I would expect to get about 4-5 years on a heater. If lower, first look at your own water checking habits. Very, very often when repairing a spa with a local customer they will insist they check the spa water weekly but by the end of the conversation they admit they check occasionally and probably didn't get it right. That is why I always recommend a good relationship with a local spa store that knows the local water. They will help, which leads me to the 2nd reason heaters fail: water source.

In parts of Denver the water is HARD. Those minerals attach to the element and cause it to fail. With a local, quality chemical source they can walk you through dealing with local water. If you have pure surface water deposits aren't a big problem but most of us don't have soft water so it is. But this again helps us to understand having a local retailer walking you and checking your work will give you longevity with your heater. One OEM of heaters claim if the customer keeps their water quality HIGH that the heater will last for a long, long time.

How to Test a Heater? Heaters work by resistance. To test a heater you must be able to use a volt/ohm meter.  With spa's power OFF, set the meter to OHMS. Place one probe on each heater post. You should have 10-15 ohms resistance. If not, you heater has likely failed.


Copyright 2021 Clear Creek Spas