Help with Laars Lite 2 LG175P Spa Heater

Reply

  #1  
Old 03-19-08, 10:16 AM
Member
Thread Starter
Join Date: May 2007
Posts: 15
Help with Laars Lite 2 LG175P Spa Heater

Hi, new to the forum and looking for some help. I have a Laars Lite 2 propane spa heater (installed in 2000), and the performance over the years has been inconsistent. The heater sits outside (Florida). It generally doesn't fire up on the first try, until I (don't laugh) give it a few good whacks on the front with the palm of my hand. I have periodically cleaned all wiring contact points, which seems to help, and also replaced the pressure switch. Last summer I was hit with a very high propane bill, and discovered a leak where the pilotstat power unit (iI think) seats into the valve body. Since there was no apparent way to remove this thing (looked kind of like a recessed spark plug in valve body), and all shops wanted about $500+ to replace the entire valve, I filled the area around the switch with epoxy - leak solved.

Now my new problem - Spa would not fire at all yesterday, I went to clean contacts. When I pulled the valve wire from the valve (TH), the connecting tab broke off. Since there is a screw terminal on the (TH) part of the valve, I crimped a ring terminal to the TH wire, and screwed it down with the existing screw. I would assume this would work. Still the unit would not fire..... Not sure if related, but now the pilot light will not stay lit. It will stay lit when I keep gas control knob (set at PILOT) pushed in, but will fizzle out after releasing. Also to note, my 100Gal tank is at about 20% - not sure if related.

So my questions:
1) How can I keep the pilot lit/steps to troubleshoot?
2) How can I troubleshoot the rest of the electrical system? I've done it with the switches by disconnecting and using voltmeter. But where to measure for voltage readings (and what should they be?)

Thanks and I hope there is someone out there that can help
 

Last edited by WannaAppliance; 03-19-08 at 10:43 AM.
Sponsored Links
  #2  
Old 03-19-08, 12:09 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
More information

I checked the voltage between the pilot generator and the pilotstat power unit (PP-LEAD on Powerstat). It sticks at about 80mV. When I disconnect the leads from the pilot generator, and measure the voltage across the leads, it was up to 300mV and kept climbing.

Anyone know how to test the Pilotstat power unit?

Thanks!
 
  #3  
Old 03-19-08, 12:37 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
More information

I checked the voltage between the pilot generator and the pilotstat power unit (PP-LEAD on Powerstat). It sticks at about 80mV. When I disconnect the leads from the pilot generator, and measure the voltage across the leads, it was up to 300mV and kept climbing.

Anyone know how to test the Pilotstat power unit?

Thanks!
 
  #4  
Old 03-19-08, 01:30 PM
todrut's Avatar
Member
Join Date: Jun 2007
Location: USA
Posts: 1,212
you should be getting 450mv or better from pilot generator, sounds like you have a bad one which will cause your issues...
 
  #5  
Old 03-19-08, 06:03 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
Thansk

Is that under load? Or with the leads disconnected and attached to my multimeter?

I am wondering if something in the valve is pulling the volts down (perhaps short?)
 
  #6  
Old 03-19-08, 06:06 PM
todrut's Avatar
Member
Join Date: Jun 2007
Location: USA
Posts: 1,212
That is while connected to valve. I have never heard of A short in the valve. I would replace pilot generator.
 
  #7  
Old 03-20-08, 09:12 PM
Member
Join Date: Dec 2004
Location: So. Calif.
Posts: 540
your thermocouple provides the voltage, the flame heats up the thermocouple & this in turn is converted to d / c voltage in your case its very small as Toddrut pointed out 450 millivoit or 1/2 of one volt [ not very much power ] if you connect one lead to your millivolt wire that is connected to your gas valve , [ remove the other one at this time ]
you should read the max the thermocouple is putting out it may go up to 500 or 700 m/v you can follow the wiring up through the hi limits [ 2] through the psi switch and through the toggle switch, and the t. stat & culminating at the gas valve, if you start out with say 500 m/v you should have right at 500 m/v on the returning wire to the gas valve, then when you connect the wite to the gas valve it will drop to around 250 m/v & the heater should fire , if it drops further the pilot will go out,
which would indicate a faulty gas valve.

steve
 
  #8  
Old 03-28-08, 02:09 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
Thanks Steve. I just replaced the pilot generator, and was expecting great results... but I did not get them. The voltage across the terminals, while connected to the valve, with the new pilot generator, about 100 mV. This does keep the pilot lit, but the valve will not fire. I am off to do a bit more testing. Any other hints would be great!
 
  #9  
Old 03-28-08, 02:25 PM
todrut's Avatar
Member
Join Date: Jun 2007
Location: USA
Posts: 1,212
Couple things could be the issue now first are you getting your mv now? Have a good strong pilot flame? If so then problem is probably in your safety loop, check pressure switch first, high limit, thermostat, on/off switch, and roll out sensor. good luck
 
  #10  
Old 03-28-08, 03:37 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
Thanks, but I am not sure if that is the problem. I just disconnected ALL wiring (i guess that would constitute the safety loop) from the valve, EXCEPT for the pilot generator leads, and the lead which goes to the "pilotstat power unit (looks like spark plug screwed into the valve). The voltage under load is still only around 100mV.

From the circuit diagram, this shold be nothing more than than the circuit which keeps the pilot lit, and keeps the voltage steady. I am confused as to why the pilot generator voltage remains so low.

As far as I can tell, the pilot flame looks good, and the positioning of the pilot generator is fixed. There is a pilot flow adjust screw in the valve, but that apeared to be pretty loose (I am assuming loose means more gas flow), and when I moved it around it really didn't have any effect on the voltage.

The only components left (I guess) would be the Powerstat Pilot Unit (which I don't know if it is replacable), or the valve itself, correct?
 
  #11  
Old 03-28-08, 04:44 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
And some more information:

With all circuits again attached to the valve, I just noticed the following:

When lighting the pilot (pushing and holding IN the gas control knob) the pilot generator voltage is around 500mV. But once I turn the gas control knob to the ON position, the voltage drops to about 90-100mV. The pilot does remain lit. I also jumpered TH to PP/TH (shorting protection circuitry), which from the circuit diagram should cause the unit to fire up (I think ) But it didn't

Ideas?
 
  #12  
Old 03-28-08, 05:00 PM
todrut's Avatar
Member
Join Date: Jun 2007
Location: USA
Posts: 1,212
that is not enough mv to fire heater, what happens sometimes is spider will have a web in the pilot and cause the flame to not come out on the generator very well. Still sounds to me to be a generator issue. A small piece of wire long enough to reach pilot is good to clean, bend the tip so you have a small hook and run it in and out the pilot holes.
 
  #13  
Old 03-28-08, 05:05 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
Thanks again.

The flame is good... I had the whole unit out today, and scrubbed up where the flame comes out. Isn't it odd that the mV is fine when I am in the "LIGHT PILOT" position, but instantaneously drops when i move the switch to the GAS ON position?
 
  #14  
Old 03-28-08, 07:24 PM
Member
Join Date: Dec 2004
Location: So. Calif.
Posts: 540
hate to tell you what you probably allready know,

1. you have 500 m/v untill you turn on the gas valve , thereby it drops to 100 m/v [ not enough power to open the gas valve ] the gas valve itself will have to be replaced.


steve
 
  #15  
Old 03-29-08, 01:11 AM
Member
Thread Starter
Join Date: May 2007
Posts: 15
That is what I am thinking...

Perhaps either of you can answer this question: The replacement valve through pool parts stores is about $300-$400. In looking at the label on the valve, it is a Honeywell VS820H2057. I unfortunately cannot find ANY information (cross reference, specs) about this valve. Do either of you know what honeywell valve could be used as a replacement, i.e. new model?)
 
  #16  
Old 03-29-08, 06:38 PM
Member
Join Date: Dec 2004
Location: So. Calif.
Posts: 540
you might check on e-bay , any m/v propane gas valve for your size heater will work , like a car doesn't know if the carb is a g.m. ford. or mopar as long as the cfm is the same, so goes for your gas valve rather its for a teledyne laars, purex, hayward, raypak it doesn't matter, but it must be for propane and same btu most in / out size is 3/4 inch good luck

steve
 
  #17  
Old 03-31-08, 07:32 AM
Member
Thread Starter
Join Date: May 2007
Posts: 15
That is what I have been doing. There are options much cheaper than the "Pool Company" version, but some of them have different regulators, etc, which I don't know enough about to make an accurate assessment. I called honeywell direct, and since this is an OEM part, they have no suggested replacement part number. So I am now calling the spa heater manufacturer, but I can only assume they will want to sell me their more-expensive-but-the-same valve
 
  #18  
Old 03-31-08, 12:51 PM
Member
Join Date: Jul 2005
Location: New York
Posts: 723
The important thing on getting a replacement gas valve is getting a VS820 series. According to my records the VS820A1054 replaced your obsolete gas valve. There are vendors on the web sell this valve for $145 and change.
 
  #19  
Old 04-01-08, 06:05 AM
Member
Thread Starter
Join Date: May 2007
Posts: 15
I have looked at this valve, but all descriptions say it is for Natural Gas only. I have propane.
 
  #20  
Old 04-02-08, 02:34 AM
Member
Join Date: Jul 2005
Location: New York
Posts: 723
Originally Posted by WannaAppliance View Post
I have looked at this valve, but all descriptions say it is for Natural Gas only. I have propane.
Oops, sorry. In that case you will need a conversion kit for the valve to switch it from natural gas to propane.

When changing the gas valve you will need to have a manometer handy to properly adjust the gas flow pressure. Failure to do so could create a hazardous situation. A manometer is a pressure gauge that measures inches of water column (smaller than PSI, pounds per square inch).
 
  #21  
Old 04-02-08, 05:24 AM
Member
Thread Starter
Join Date: May 2007
Posts: 15
Sounds like it could be complex.... I will most likely purchase the exact replacement valve, then call my propane company to install....

...Unless it is something an avid do-it-yourselfer can handle (with proper guidance of course)
 
  #22  
Old 04-02-08, 01:09 PM
Member
Join Date: Apr 2008
Location: Overland Park, Kansas
Posts: 23
You said your tank is only 20% full. I know when those tanks get low they can cause all kinds of funny problems so I would fill it. Then when you jumper the gas valve it should open. Make sure its set to on/run. Another thing you can try is aiming a small propane/butane torch on pilot generator to really get it hot. If you pilot stays lit with valve on it should fire. You also said before, you used to have to hit the heater to get it to fire. It sounds like its sticking, so as your torching the generator and jumping the gas valve, take a hammer and hit the side of gas valve pretty hard. If its truly stuck shut after beating it to death then replace the valve with a Propane valve only. I think a Purex/ PAc FAb 3/4" valve is alot cheaper and will work. Hope this helps
 
  #23  
Old 04-02-08, 02:01 PM
Member
Join Date: Jul 2005
Location: New York
Posts: 723
Originally Posted by WannaAppliance View Post
Sounds like it could be complex.... I will most likely purchase the exact replacement valve, then call my propane company to install....

...Unless it is something an avid do-it-yourselfer can handle (with proper guidance of course)
I would recommend doing exactly that, ordering a replacement (as close to exact as possible) and having your supplier install it.

The most important thing with the gas valve is you have 3/4 inch female threads in and out and its a millivolt only gas valve. Because there are all different types of gas valves out there, and it's easy to get confused, get an exact replacement to the number on the valve.

An avid DIY'r, with guidance, may be able to handle it. But even those with the best of guidance could fall short of the desired result. Being it is propane you are dealing with, it's not something you would want to fall short of and find out the hard was as the gas will bite hard (burn) if you are not careful and take the proper precautions. Being the gas company shouldn't charge more than an hour labor I believe it would be money well spent.
 
  #24  
Old 04-02-08, 07:06 PM
Member
Thread Starter
Join Date: May 2007
Posts: 15
Red face

Thanks everyone for your support on this forum. Since I started the thread, my propane tank is now full, so low gas not a problem. I also whacked the valve several times with a hammer... And finally, I verified my voltage measurements with my neighbors. Under load, his voltage is about 500mV. Mine, with a new pilot generator, strong pilot, and all protective circuitry removed is 100mV.

Gas company is going to replace with a Robert Shaw (700-511) valve. The "parts charge" is only $20 more than I can get it online, so I am going to have them bring the part, do the install and wash my hands of this . Heck, I may even get to use my spa (with hot water) sometime soon.

At least I know how the thing works for future reference!
 
  #25  
Old 04-03-08, 03:49 PM
Member
Join Date: Jul 2005
Location: New York
Posts: 723
For $20 more it's well worth having the gas company take care of it. This way should this is not the cure, it will be on them to take back the gas control valve.

Please post the outcome of what happens.
 
  #26  
Old 05-05-08, 04:59 AM
Member
Thread Starter
Join Date: May 2007
Posts: 15
So many weeks later, my gas company finally came out and replaced the valve. My frustration level was pretty high, as every week I got the same response about "waiting on the part." Not sure how, since I called 3 other gas companies that had the part in stock! So as a courtesy they waived the install charge. Not everything runs like a champ!

I did watch him replace the valve (i.e. remove the whole burner tray, etc). He also found an intermittent connection to the "fusable link," and replaced that wire.

Thanks for all the advice!
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'