Sunday, March 2, 2008

LF Low Flow Heater Dry Error Codes

Why is my spa not heating? What does LF mean? This is a very common problem, and fortunately there are some simple solutions.

Luckily, your spa may be smarter than a fifth grader. It can sense when there is a reduction of water flow passing through the heating system. When this reduction of water flow happens, your spa is designed to shut down the heating system, protecting itself from overheating or burning up altogether.

The most common culprit is a dirty and clogged filter element. To troubleshoot this, take the filter(s) out of your spa completely. Be sure there is nothing floating in the spa water that could get pulled into the plumbing, i.e. leaves, scumballs, etc. Turn the breaker to the spa OFF, and then cycle it back ON. Keep your filters out of the spa, and determine whether the LF error code has disappeared. If it has, close the spa lid and check back in a couple of hours to see if the spa has heated. If the dirty filter(s) are returned to the spa, the condition will repeat itself. Either replace the spa filters with brand new ones, or clean your existing filters with a filter and cartridge cleaner from your local spa store. Rinsing the filters with just water isn't going to do it.

Have you just refilled your spa? If the spa was working fine prior to a drain and refill, but now it isn't, chances are you have an air-lock. If your spa is equipped with a priming mode, turn the breaker OFF and ON. This may do the trick. If not, you must open the access panel on the spa, and locate the correct pump. Some spas have independant circulating pumps, and some use the jet pump on low speed to circulate and heat the water. If you aren't sure what pump it is, try to see if there is a pump that is just humming. Chances are, that is the one. The air must be bled out of that pump by the drain plug or by loosening the PVC union that connects to it. The spa should be powered down before you loosen any pump plugs or unions. Once the air is let out of the pump, it will operate correctly. Thus the LF error code should not appear once the spa is powered back ON.

Is your water level low? Top the spa off to correct level, and cycle the spa OFF/ON.

Is there a screen in your spa that hot water comes out of? If your spa is equipped with a circulating pump, there is a screen-like fitting in your hot tub that bubbles and/or hot water comes out of. Sometimes solids, leaves, hair, etc. can clog this return fitting. They can be removed and cleaned, and should be each time you drain your spa. There is no problem removing this screen when the spa is filled. Grab your suit and jump in! Depending on the make of your spa, you may need a screwdriver.

Does your spa have a pressure switch? Some older spas, and even some new ones have pressure switches. They are usually 1-2 inches in diameter, round, and attached in some fashion to your heater. they may have 2 plastic "flags" that protect some wire connectors. If all else has failed, and your spa is equipped with one of these troublesome components, you probably need a new one.

These suggestions will solve 99 percent of all LF issues. If you have any other questions or problems, please call us at 734-668-7665.


kyle james said...

thankyou, that fixed it!!!

Lucky923 said...

Thank you for a great post, it fixed mine as well!

Ironman101Qc said...

Thank you, it fixed!!!!!! :-)
Merci beaucoup très bon conseil, le tout fonctionne enfin! :-)

Unknown said...

Fantastic post. Fixed mine and very happy :-)

Karen Hirschey said...

Thank you, thank you, thank you! Supposed to be heading into single digits next week and I was a bit stressed.

Unknown said...

Mine came up with Dr dry pump. But when you select high power pump it pumps as should. But in general heating mode you can hear the pump humming but not pumping. Pump motor does seem warm when this happens. Any ideas?

Michelle said...

I keep getting the low flow error only when the filters are in place. The filters are brand new so this isn't making any sense. We've had a technician here as well that can't seem to figure it out - first he thought the circuit board was gone so it was replaced, it's been snaked out for any blockages, we've drained and refilled twice. Help!! This is costing a fortune and I'm about to take it to the curb!! Appreciate any suggestions

Jerry B Sheldon said...

My Thermodynamic Little Magic Box system is not heating my water properly. The panels go white with ice which looks dreadful on the front of our house.

miffed solar guy said...

The low-speed has gone out on your pump if it hums, if it just doesn't turn on that could indicate an issue with the control board the pump needs to be replaced if it is humming and not running

miffed solar guy said...

Even though the filters are new if you are not cleaning the filters with a solution body oils may have coded the filter and block the flow to the water. Or it could also be a pressure switch.

Jones Morris said...

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Unknown said...

Very helpful thread! I still need help!

I keep getting a LF, DR, or HFL reading

- Balboa M7 heating unit (brand new, i just replaced).
- 2 pumps - Waterways Executive 56, pump 1 seems to be working on high & low, pump 2 is working.

I have:
- allowed for priming to take place
- removed filters during this process to make sure they aren't the culprit
- tried addressing a possible air lock (however pumps are moving water). addressed air lock possibility at, heater, pump1 & pump2 & spa drain.

Balboa M7s don't have a pressure sensor.

I am out of ideas. I am reading about the heater relay? Anyone have pointers? Please!

Subarna Akter said...

I truly like it & helpful. Thank you

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james mitchell said...

Did you manage to fix this