Lite On Heating & Cooling - Page 3 - Recent Questions, Troubleshooting & Support

Depending on the safetys provided on this unit it looks like the Flame Sensor is bad.. The unit will light in normal mode and once the unit is expected to be running full flame it goes through a verification of flame process.. Either by use of a thermocouple or "fireeye" type product. If its an eye it will have one wire going to it and then another going back to the board or controller. SOmetimes these will have a small reset switch on them.. let me know what you find so I can help further

check the themal couple

It is eather elec ing or have a millivolt rod which should be on the piolt assy. If not hot service or spark ing. But all will be at piolt assy.

Intermittant problems are the hardest to find as they don't show there ugly heads when you are looking for them.
Below is a place I give you for the parts break down of location and pricing, may be useful for you, go to poolcenter.com for this info.

This is an online website that gives you the repair bible for this machine I hope this all helps you as there is a lot of testing to be done http://www.poolheatersguide.com/Lite2-LJ-onlinemanual.pdf Technical support for Waterpik Laars Products is the following phone # (415) 382-8220 extension 260. I hope this info helps, you seem to be into the electrical repair end of things so all this info should lead you to a resolution to your problems, if it shows while you are testing it. Good Luck, any further questions on this call there technical support hotline. Good Luck!!!

I have had the some problem but with no luck with a Repairman figuring out the problem. Also, the Laars manual does not mention trouble shooting the problem that I have discovered. Try this: with the pump off, remove the water line from the pressure switch and put a small bucket on the end of the line and turn the pump back on briefly to see if you get good water flow coming out of it. If not, then you have the same problem that I have with scale build-up in the header that is clogging the pressure switch line to the pressure switch. I have to periodically remove the line at the header and use a small piece of wire to unclog the scale in the header. Also, you should use a compressor to clean out the copper line in case there is scale clogging it. Once you have cleaned it out then you will hear suction (with the pump off). Reinstall the line to the pressure switch, turn the pump back on, and the heater should fire since your pilot light is still lit. It will take half a minute while the pressure line and switch fill up with water and pressurize. Hope this works for you also.
P.S.: And my heater is only 3 years old!

Hello Keith,

Verify that you have the correct switch. When it senses proper pressure, you should read zero (or nearly so) resistance through the switch. Disconnect 1 wire (either one), and use a multimeter to check the resistance If the pump is working like it should, bypass has not been monkeyed with, then the switch should indicate very little resistance.

If the switch has not closed, when it normally should and you are positive that you have adequate pressure, you can try adjusting the pressure switch until it closes like it needs to.

You should be using a switch that is normally open, and closes to complete the circuit when pressure requirements are met. I suspect that you might have a valve that is normally closed, and opens when pressure is present.

The easiest, and fastest way, to see if the switch is wrong, turn off the pump, and try to light the heater. If it does light (with zero water pressure, quickly turn it off, and start looking for the correct switch. If the heater still doesn't light when pump is off, turn the pump back on, and adjust the switch until it comes on (per manual, of course).

short pilot needs cleaning loose thermocouple at nut end , thermocouple might need replacing

Thermocouple, if the pilot comes on while holding down the gas switch/button and goes out when you release to turn on, the thermocouple is bad.

It may also be the high temp switches under the 2" inlet/outlet header. The 150 degree high-limit switch sits horizontal and corrosion happens often there. But be careful removing as if the header is corroded and the switch is also, water will flow out , so be ready to bypass the heater. You will have to replace the header. Try to jumpe that switch out and I'll bet the heater fires up.

Hi, on most all heaters you will have a chart somewhere on this unit, a code chart that will tell you what it means. It had to try and fire 3 times before it locked the module out do to a open safety switch, flame roll out switch, or a open pressure switch. Look, as they paste them on a panel or somewhere on the unit. If you have no luck, please use my user name below and I will look into it more for you. Send me all of the information to this unit. Keep me posted.
Sincerely,
Shastalaker7
A/C, Heating, & Refrigeration Contractor

The flashing light is the service code telling Joe blow that there is something wrong. As you didn't tell me the brand of car I can't tell you what that code means. Some cars will trip out a code based on milage. ( Company Scam ),

Please reask with more details. THX Ash.

Hello KIRK Yes it will by-pass the switch BUT if it is low pressure/restricted flow the swtich is doing its job!Check flow first! you could make dangerous STEAM if you run it with low flow & the saftey switch jumped out.

It should be at 750 mv or a bit less if in the system under load, test it out ot system, make sure flame is at the tip of the pilot generator, as the temprerature differentail across its body is what creates the 3/4 volt or 750 mv. easier to simply buy one, test the valve using a AA battery with a wire taped on each end, simulate a pilot generator by attaching the wires where the generators wires went, if it works its ok, and generator is bad

sounds like the hi limit switch is shutting it down,because it is not getting enough water,cloged filter, valve to heater notopen,bypass valve not closed,open up the water releif valve with the pump running should be alot of water running coming out of it.

laars use to put the model number on the back of the door cover.

The fuse link is a saftey for flame that is rolling up into the cabnet,There are a few things that will make this happen,down drafting from wind,cloged flue,burners cloged,gas pressure.Turn it on with the cover off and stand back look to see if any flames are rolliing up near the fuse link.

I take it you are talking about the powerphile which will give the readings you have , check pilot is not blocked , do the leads from the powerphile go on to the valve with out any other conections in the wire as this will drop the volts and it will not work , check thermocouple is tight and is in the flame from the pilot ,

If thermopile generates 700mv...the stat is ok and no open limit then it is bad valve...touch the 2 thermopile leads direct t TH and PP on valve to bypass limit and stat...if it works direct...then a limit or stat is open

clean pilot might be small , or change thermocouple