Laars Lite Pool Heater won't keep running

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Thanks for the feedback I'll post some more pictures later today and will try and orientate them correctly. Liked your comment on standing on your head to look at them Paul. LOL

I agree, don't think the tech really knows what he's doing, and with your help I can probably just figure it out by myself. :)
 
Just throwing this out. May or may not be relevant. The wires that go to the gas valve are typically to energize/ de-energize coil(s)/solenoid(s). If the heater, (didn't look) is a pilot type heater, you would need all three wires. One ground/common(MVPV), one for the pilot solenoid (PV) and the other for the main solenoid (MV). if an ignitor type, just two (MVPV and MV). The thing about replacing old valves is that they are now "universal" and will, or supposed to work on several different heaters. Hopefully the destructions you get with them will guide you through the install, but only if you are capable of interpreting the dialect known as "vague".

+1 on getting another tech to look at this.
 
Based on some other posts I've read it might be a faulty control board, if so people have replaced the existing board Fenwal 05-339011-003 with the following item: http://www.patriot-supply.com/products/showitem.cfm/FENWAL_35_652505_003

They are essentially the same except the new board has a 20 second heat up for the ignitor instead of a 7 second heat up, but apparently it still works. If I can't get the existing wiring to work I think my next step would be to replace the board. Sounds reasonable?
 
Stewart
what terminals on the old valve were the two yellow wires connected to? according to the schematic they both should have been on the MV 2 terminal, or the lower one (really does not make any difference on that valve as it was a two terminal valve)
 
I'm not sure which where they were connected on the old valve as the pool tech replaced it. Based on a picture I took a while ago I think (the picture is not very clear) both yellow wires were combined into one connector and were connected to the middle terminal, which would mean that the lower terminal would be the brown terminal, would that be the correct wiring? If so, then it definitely isn't connected correctly now.
 
OK, that makes sense now. This is the connector view on the current valve you have.



I would try putting that adaptor in and connection the two yellow wires to one pigtail and the brown to the other. unfortunately the instruction sheet fore that valve does not show which wire to connect to which lead. Being a DC system though it may not matter.


Something is still bugging me though on the terminal designations and the way that harness adaptor is wired.
 
White wire on adapter is MV and connects to the brown wire (marked "valve" on fire box), no other connections or splices on that wire. Black wire (on adapter) is the ground/common or Yellow connection. Yellow wire should come from x-former and go to the GND on the fire box AND go to the black wire on gas valve AND yellow wire on up to the thermostat. There are other things you can check before you go and buy a (thermostat) board. First thing to do when you get it all hooked back up and try to fire is to verify that the HSI is glowing. A good way is to use a mirror on the floor of the heater just below the location of the HSI. If you have glow, all safety switches have been satisfyed, and your problem is narrowed (back) to the gas valve. Don't forget to turn both the gas valves back on. On gas valve itself and valve outside heater jacket.
 

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Ok, so progress, after installing the adapter the valve started clicking and the burners came on! Haven't had chance to run it for anything more than a few minutes as it was dark and drizzling. However the valve (or possibly the control board as well) constantly clicked the whole time the burner was running, is this normal? The last valve did the same thing and the burners would go out intermittently. I'll give it a longer test run tonight and see if it stays on for an extended period of time. Still concerned about the clicking, didn't always do that when it was working properly.
 
OK, looks like we are getting somewhere. The clicking is the solenoid in the gas valve opening and closing...should not be doing that. It may not be closing all the way but, non-the-less it should energize and stay open, one click. Did you check the output voltage from the transformer? Should be min 24 volts. This should be checked when the gas valve is energized to see what the voltage drops to with a load. I have seen too many transformers that read good at idle but drop off when a load is applied. Also, if possible, check all connections for tightness and corrosion. A loose or corroded connection in the safety circuit or any other wiring that controls the voltage to the valve can drop voltage enough to cause problems.
 
Sounds as if the fire box (Fenwal) is getting a bit wonky, or x-former voltage is dropping off (as said above). There is a small relay within Fenwal that feeds the voltage to the gas valve solenoid. If that relay is failing, you would get the chatter or clicking in the gas valve you are describing. You may be getting the chatter on the Fenwal relay as well, however, that relay is real small and the gas valve makes more noise, so you probably cant hear it. Check for proper x-former voltage (again, as advised above) . If good under load, probably Fenwal.
 
Where is the transformer located, is it the item just above the control board? Can I just check it using a meter I get from the hardware store, I assume I just test it on the connectors. Sorry I'm pretty ignorant when it comes to circuit boards which is a pretty sad when I'm in IT.

When you say energized (or under load) I assume that means when the heater is running and I'm hearing the clicking sound.

If it is the Fenwal (circuit board) then I guess I'll need to replace it, will this part work Fenwal 35-652505-003, the original part is 05-339011-003 but they don't make it anymore?

How difficult is it to replace the circuit board, is it something even a caveman like me could handle or am I way in over my head here?
 
stuartbarnes said:
Where is the transformer located, is it the item just above the control board?
Click to expand...
Yes, the red and yellow wires are the low voltage (24v) wires that you need to test. Be careful though, the wires on the other side of the transformer are line voltage. They should be inside a work box but, just in case, be carefull
stuartbarnes said:
Can I just check it using a meter I get from the hardware store, I assume I just test it on the connectors.
Click to expand...
Yes, it may take some work to get to each connector with the wires hooked up.

stuartbarnes said:
Sorry I'm pretty ignorant when it comes to circuit boards which is a pretty sad when I'm in IT.

When you say energized (or under load) I assume that means when the heater is running and I'm hearing the clicking sound.
Click to expand...
Yes. When the heater is running it is drawing power and a weak transformer will not be able to keep up.

stuartbarnes said:
If it is the Fenwal (circuit board) then I guess I'll need to replace it, will this part work Fenwal 35-652505-003, the original part is 05-339011-003 but they don't make it anymore?

How difficult is it to replace the circuit board, is it something even a caveman like me could handle or am I way in over my head here?
Click to expand...
When it is running, feel the valve with your hand, you may be able to feel the "clicking". Do the same with the controller. Not sure on the replacement as I did not look it up but, it should be easy to replace
 
Ok, went to test the wires with a voltage tester and it fluctuated around 20V. Turned it on and it ran fine, valve clicked once and open and stayed open. It Seemed to work fine for around an hour or so and then once it gets up t temperature (102 degrees) it does not stay there. The heater turns off and then starts clicking again. I checked and the flames were out. I turned the unit off and left it for 15 minutes and turned it on again and the same clicking sound was back. I checked the voltage and there didn't seem to be any. Kept checking and it looked like the voltage was fluctuating wildly. I suspect it might be the transformer, or perhaps maybe its the high-limits?

For the transformer do I need to replace it with the exact same model or will any 24V transformer do?

The existing transformer looks pretty old and rusty. The model number is E0097400.
 
Also forgot to mention, as I was testing as the voltage and the valve was clicking to come on, the burners finally lit and a flame engulfed the underside and side of the unit (I guess the gas was running but not lighting) and it burned some hairs off my arm. Nothing serious, but either the valve was either open too long, or the burners aren't lighting early enough but pretty scary. I still suspect the transformer is faulty and the voltage fluctuating is causing the issue, but maybe its some of the sensors not working. Any help is greatly appreciated.
 
stuartbarnes said:
For the transformer do I need to replace it with the exact same model or will any 24V transformer do?

The existing transformer looks pretty old and rusty. The model number is E0097400.
Click to expand...

Any standard 24 volt 40VA transformer should work. Do not use a lower grade doorbell transformer as the VA rating is too low to power it. An electrical supply house or heating supply house should have a universal fit transformer to install. Make sure the power is disconnected at the source as you will be working with 120 volt lines when unhooking and connecting the new one.
 

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