Rapak Heater wont fire up burners

[pooly1]

Hi guys
I have a Raypak P-R185 I believe manual controls. I moved into a house with it. The pilot light will fire up and stay on but the burner wont fire up. I tested the sensors with a multimeter by following directions in the manual and ended up changing the thermocouple. Now is their a difference between pool heater thermocouple and a standard furnace style one?

 

[Pool Clown]

If pilot stays lit, then thermocouple is OK. Make sure thermostat is turned up, and that pressure switch is closing when the pump is on.

 

[pooly1]

Okay thanks for the tip

 

[ps0303]

You really need to follow the entire circuit to see which part is bad. So follow the diagram and start with one test lead and follow the circuit all the way thru to see where you are dropping out. I usually start with one lead on the gas valve and then follow the circuit all the way thru. Milli-volt heaters are sometimes a pain in the rear to diagnose. In fact sometimes a volt meter might not detect the quick voltage drop. I test probe with a light or buzzer works well.

 

[pooly1]

Great tipe thanks!

 

[pooly1]

Started troubleshooting and was following a diagram in the back of the manual, it says to jumper TH to TH, now this worked the first time and the burners fired up and ran but as soon as you remove the wire they turn off. So when I tryed it again the unit made sort of a click noise sort of like a relay but a little more like a thump when I jumped the TH and the pilot went out. Anyone have any ideas coul the thermostat be causing this?

 

[ps0303]

It shut off because you weren't supplying power to it any more. If you have no pilot then the unit shut down the portion of the valve that allows the small flow of gas to keep it burning. The thermostat senses water temp and doesn't put out the pilot.

A word of caution: When working with gas and other things you really might want to consider a licensed contractor. Consider the value of your life and others around you. I realize people are all about saving money but lives are priceless!

 

[danpik]

It could be any one of the various sensors in the circuit. When you initially jumped across the th,th/tr terminals you effectivly bypassed all the sensors and controls (thermostat) in the system. Think of the wiring circuit as a string of miniature christmas lights (you know the ones...One goes out they all go out) If one of the sensors fails to make the circuit the power never gets past it and the system wil not work. Trouble shooting this can be a little time consuming but it is by no means hard to do. follow the wires from the gas valve and see where they go. One of them will daisy chain back to and thru all of the sensors. Make youself a short jumper wire and one at a time unhook the wires from a sensor and connect them together with the jumper wire. When you find the guilty culprit the burners should fire right up.

 

[twmackey]

Try checking your high limit sensor. On Teledyne Laars EPM 175 is located right under the return lines cover by a metal cover and then a clip to hold the sensor. There are 2 sensors 1 is for 135 degrees and the other one is for 150. pull one of the leads out of the ruber gromet becarefull that you do not pull the leads from the spades holding the wires. jumper the sensor and if it fires then, it is a sensor. if it does't fire try the other sensor and jump it.

 

[twmackey]

Also It could be the pilot generator, which was what happen to mine. It was the pilot generator and the 135 sensor which caused it not to work. When I fired it up in may and the turned it off I could not get it to work after it was working just fine. Also what I dis was take out the berner tray and cled around the pilot light to ensure I was gettind good flame.

 

[twmackey]

Here is my thred which may help you

heater-problem-t48425.html

 

[danpik]

This is a milivolt system and thus has a powerpile generator. If the gas valve opens and the system fires then the powerpile generator is good and does not need to be replaced. Since you jumped the terminals on the gas valve and it did indeed light then the problem lies elsewhere in the system. You need to test each individual sensor, switch, and connection point one at a time with a jumper wire to determine the guilty culprit. I include connection points as well as any corrosion on a connector will cause enough resistance to prevent the system from seeing the voltage being put out from the generator. If you have access to a voltage meter, you can test the generator output, With the pilot lit you should see 750 Milivolts at the wires from the generator.