I have inherited a Hot Spring hot tub Classic Model F from my grandparents. Everything works except the heater. It is heating a little but not like it is supposed to. How do I go about figuring out how to fix it? Please help I am just longing to soak in it. " title="Laughing" />

I can help you troubleshoot, if you provide a serial number " title="Smile" /> Throughout the years, there have ben many changes to the classic... in order to point you in the right direction, we need to figure what we're looking at " title="Cool" />

if you have three filters, loosen caps on all and see if flow increases coming out of circ. pump/ heater inlet fitting in spa.

if you only have one filter, check the intake fitting in the side of the footwell to see if there's lint or a blockage of the s.s. steel screen.

circ. pump probably has low flow

Low flow is a possibility, except that in virtually every year (excet 1995, 1996, and 2005) inadequate flow would also result in a tripped high limit, either electronic or physical... depending on the serial number....

The serial number is F 231024.

If everything is working except the heater, let me ask you a couple of dumb questions before we start troubleshooting (which will be a peice of cake!)

Have you given the spa ample time to heat, with the cover on? The classic you have is 110volts, and will only heat with the pump off, the heat turned up, and the cover on. It will gain appox ~2 F per hour in this fashion, when working properly.

If you've given it enough time (at least 24 hours), then, the problem most likely lies in a faulty T-stat, failed element, burnt wire inside the control box, or a bad heater relay.

We can rule out a few things right off the bat, by performing some quick little tests...

When the pump is off, and you fully turn the T-stat dial all the way up, and all the way down, do you hear a loud "click?" The click you should be hearing is the heater relay energizing as you turn the heat up, and releasing as you turn the t-stat down.
If you do not hear the click, it's likely either a bad T-stat (very likely) or a bad heater relay (less likely, but still quite possible), or maybe even a rectifier (they used a 120v a/c to 120v dc rectifier in that particular model, and a 110v dc coil heater relay)

If you hear it clicking, you either have a bad element (likely), or a burnt wire inside the control box (less likely, but still possible)

There are a few other remote possibilities on your 1993 classic, such as the 10 minute timer pcb failing... but the chances are quite remote.

If you have an ohm meter, I'll help you troubleshoot inside the control box, if you are up to the task. It's not easy dropping that control box for the first time, but if you're handy, you can give it a shot...

I don't think a circ pump (flow) problem is currently an issue.
The heater is NOT energizing at the moment, if it was, and you had a flow issue, the heater high limit button would trip, thus leaving the entire spa inoperative.

However, it doesn't mean the the circ pump is working. It's possible there is a flow issue as well, and you just don't notice it because of the additional heating failure. Once you get that repaired, you'll know immediatley ( appox 2 minutes) if you have a flow issue as well. That's about how long it takes the heater to overheat without circ pump flow.

Good Luck!

~Swine