Watkins/HotSprings Classic F
F351538
120V
20 amp dedicated circuit

Typical I just bought a used hot tub from my buddy story.

Got it home and it worked for 3 weeks. Got hot, pump worked, etc. I was working when I bought it.

I've read a bunch of posts on here to come up to speed.

GFI reset on the end of the cord won't reset.
Unpluged the heater from the controller board...I can then reset the gfi.
Plug the heater into the board and the gfi pops immediately.

I've checked the pics and numbers and it is the original heater.

Ohm tested it
round pin(s) to ground blade 8500 & 9500 ohms
round to round 20 ohms.

Dealer is saying heater & retrofit kit. $350 in parts (PDR Heater @$280 plus a couple other parts and tax takes it to $350). Figure another $120 or so to have them make the trip and install it.

I'm assuming it can't be fixed.

My question is, since I'm doing a retrofit, is the PDR heater the one I want? Logically I can plumb any heater in there that runs on 120V, in the 1500 watt range. On e-bay there are cartridge replacements that claim to fit the tube type heaters that are $20. So why would I want to put in a heater that will cost me $280 to replace when it fails again?

Also, is there a special clear plastic tubing that is required? Or a source for that? I've done enough schedule 40 PVC plastic piping work to be able to do this job myself.


Tom

Yes, the PDR is the heater you want.
And no, you can't just pop in any heater, unless you want to replace the existing controls too.

Not special tubing, just vinyl. Most is 3/8", exept for the 1/4" bleedline. Hardware store should have what you need. If not, the manufacturer sells a retro-fit kit, which includes the varius tubing and fittings you'll need, as well as a nice little jumper to jump the flow/switch circuit.

The cartridge replacements you see on E-bay for $20, are you sure that isn't just the housing? If it includes the element, for $20, I'd roll the dice. As far as I know, the actual cartridge element isn't available anymore. While some may still have a few laying around, the cartridge style heater-body (element NOT included) is still readily available, but the element is a rare thing indeed.

The PDR heaters have been performing phenominal in the field if it's any consolation.

I would think any 1500W 120V heater should go on and off when told to by the controller. The controller is just supplying the power to the heater. But that's just me.

Here's the current ebay auction number 180041922068

He's selling 120 and 240 V heaters in a variety of Wattages for $29 each. Now obviously they won't fit my housing. I can tell by looking...But my thinking was if I am replacing the housing....maybe a different heater with cheaper to replace elements might be in order...Aftermarket or whatever.
I'm not finding any recommendations on this board for going that route though.

likely I'll just end up with the PDR as the hot tub is outside and bad weather is setting in quickly around here.


Tom

The problem at hand is the electronic temp sensors, and where to put them. They currently reside in your heater.

If you pop in a different heater, the issue isn't plumbing it into the existing plumbing, or hooking it up to power, but begs the question of how and where to install the existing thermistors. They are quite shallow, and have their own thread (neither pipe nor hose thread), so installing them into another heater would not only require new and hard to find tools, but also proper placement.
The system must use these thermistors, there simply isn't an alternative, and at least one of them must be placed within the heater housing. It is possible, but whether it's worth the headache is ultimatley up to you. I wouldn't suggest it, but maybe you have plenty of idle time...

Good luck

~Swine

Upon further review...

Perhaps keeping some of the cartridge heater plumbing (sans the old element), and you'll at least have an accurate spot for the control thermistor, keep the high-limit thermistor installed as well- it goes off at about 118F, in case the spa water grossly overheats (it can happen). Just keep that peice of plumbing in-line- modify as needed.

Just be 100% sure the new heater has a high-limit within the new housing itslef, and wire the heater through that high-limit. WHen the circ pump fails (and it will) if you don't have a high limit in the heater, bad things will result. Keep the flow/switch intact- you need at least 2 safety devices to protect in case of circ pump failure (a normal failure every 4-7 years)

i found these guys to have a wide selection of parts at reasonable prices http://actionsparepair.com/heater-eleme... l#flo-thru