Question about Raypak Rp2100 Pool & Spa Heater Lonox 407k Btu Natural Gas Polymer Header Digital Rp407aenc

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Unit ignites but then goes on/off with pressure error.
Pressure is good

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RP2100 model 277 approx 10years old. Has had 2 new temperture control panels ,2 x new pilot assemblies , new headers , burner box insulation and quite a lot of the sheetmetal has been replaced. Up untill lastseason was working well. All functions appeared to be normal.
However , currently the unit will not stay alight. once it lights it runs for 5 secs , stops nd goes through the re light process. This continues untill i turn it off . Any suggestions ???

Posted on Jul 10, 2011

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If you received the PRS error, then it is the water pressure switch. The water pressure switch, or heater actuator, ensures
that the heater operates only when the filter pump is in
operation. It is located on the inlet/outlet header. It is
factory set at 1.75 PSI for deck-level installations.
When the heater is located below the level of the spa
or pool, it may be necessary to adjust the pressure
switch to compensate for the no-flow static head. If it
is necessary to adjust the water pressure switch, Follow the directions in your manual.If your is the low Nox model, then you have a combustion fan. This has a fan air pressure switch but the error code for it is FAN I believe. If you don't have a manual you can get one at

Posted on Jul 14, 2010


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Where is the oil sending unit on a 1996 mercury cougar xr7 ? Its cause my oil pressure gauge is bouncing up and down...i dont know why...can anybody please help me thank you so much

The low oil pressure warning lamp will illuminate anytime the ignition switch is turned to the ON position without the engine running. When the engine is running, the light also illuminates if the engine oil pressure drops below a safe oil pressure level. To test the system, perform the following:
If the oil pressure light does not work, perform the following:
  1. Turn the ignition switch to the ON position.
  2. If the lamp does not light, check for a broken or disconnected wire around the engine and oil pressure sending unit switch.
  3. If the wire at the connector checks out OK, pull the connector loose from the switch and, with a jumper wire, ground the connector to the engine.
  4. With the ignition switch turned to the ON position, check the warning lamp. If the lamp lights, make sure the oil pressure switch is properly grounded in the cylinder block, and if so replace the oil pressure switch. If the lamp still fails to light, check for a burned out lamp or disconnected socket in the instrument cluster.
To diagnose an oil pressure light that stays on, perform the following:
  1. Check the engine oil level and top off as necessary. If the engine was 2 or more quarts low on oil, test start the engine after topping off the oil level and recheck the oil pressure light operation. If the light stays on, stop the engine immediately and go to the next step.
  2. Disconnect the wire at the sending unit, then turn the ignition switch to theON position. If the light remains on, check the wire from the sending unit to the gauge for being shorted to ground and repair as necessary. If the light goes out, turn the ignition switch OFF and go to the next step.
  3. Replace the oil pressure sending switch with a known good switch.
  4. Start the engine and check the oil pressure light operation. If the light stays on with the engine running, stop the engine immediately to avoid severe engine damage until the cause of the problem can be determined.

If the oil pressure light remains on while the engine is started, stop the engine immediately. Do not operate the engine until the cause of the problem can be determined. Operating an engine with low oil pressure will cause severe internal damage.

Possible causes for an oil pressure light to stay on are:

Pinched or grounded sensor wireDefective oil pressure sending unitRestricted or severely leaking oil filterExcessive internal engine bearing clearance.Insufficient or severely contaminated engine oilBlocked oil pump pickup screen or severely worn oil pump

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Pentair mastertemp 250 NA. heater will not fire, no error codes. starts fine, gas flows, igniter heating but still will not fire. It has a new valve, gas pressure entering valve from new regulator is 8.35...

All appearances - No fuel to ignite!
evrything else looks good, proper gas pressure, proper volts at igniter, etc - it should ignite! If fuel present, heater should Fire!
make sure all valves are open.
Gas valve is ON
AND purge any air from gas line.
IMPORTANT ****. If you bled gas line, don't try to ignite for a few minutes. Allow gas to dissipate first, use a fan to help.

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Neutral and oil light not working on 2007 street glide

Oil light switch is a normally closed unit so first off test with an ohmmeter to see if there is an open which would not complete the circuit not allow the light to work.Then check to see if there is any current to the oil switch. If there is you could jumper the wire to ground which if the light then goes on indicates that the switch is bad. If no current to the switch you will have to trace back and find out where the open in the circuit is.

There may be no oil pressure due to lack of oil or a faulty oil pump. Check the oil level and add oil if low, then restart the engine and verify that the oil pressure light goes off and that the oil gauge indicates pressure. If the problem still exists you will need to check out the oil pump.

If the gauge shows oil pressure but the light does not go off it may be that the contacts in the pressure sending unit are not opening to break the circuit and shut off the light.
If the gauge does not show pressure it may be that the variable resistor in the sender is shorted to ground.

Locate the oil pressure sending unit on the front right side of the crankcase and verify that the electrical connector is properly connected to the sending unit. If the oil pressure gauge indicates pressure but the low oil pressure light remains on remove the electrical connector from the oil pressure sending unit and using a small jumper wire place one end on the indicator lamp terminal (the closest to the latch on the sending unit) and place the other end on the crankcase. The Ohmmeter must read less than one ohm. THEN start the engine and run at a fast idle. The ohmmeter must read infinity (OL). Replace the sending unit if the above meter readings are not obtained.

If the low oil pressure light functions correctly, but the pressure gauge does not, remove the electrical connector from the oil pressure sending unit, turn the ignition switch to IGNITION and the gauge must read zero. Ground the (BN/GN) wire terminal to the crankcase. The gauge must read full scale (60 PSI). Replace the sending unit if the above gauge readings are obtained but if the gauge readings are not obtained, replace the pressure gauge.

If there is no power to the gauge diagnose the cause could be broken or disconnected leads to the gauge or an open gauge winding. Test by switching the ignition switch to IGNITION and verify that 12VDC is present at "+ terminal on the gauge, then with the ignition switch turned to OFF check the ground terminal for continuity to ground. Replace the gauge if 12VDC is present and ground terminal is grounded. If 12VDC is not present, trace wiring until disconnected or broken wire is found and repair as necessary. If ground terminal is not grounded, repeat the procedure used to trace a for 12VDC lead.

The power lead fro the oil pressure and neutral switch is an orange wire on pin 6 of a 10 pin connector.

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How to prime oil pump

Disconnect ignition components (distributor/spark plugs) and crank engine until oil light goes off or you have pressure on the guage, then reconnect ignition and start the vehicle making sure the oil light goes out or gauge is showing good oil pressure

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Caterpillar 330cl c-9 engine ecm reading low oil prressure and the manual guage shows the correct pressure

change the oil pressure sending unit on the eng. if this goes bad it sends the wrong voltage to the computer which will then detune the engine to reduce the chance of damage due to low oil pressure . Good Luck

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Heater fires and shuts off repeatedly. reads CHF. Has good flow.

error code should be inside heater make shure you have adequate gas pressure also sounds like bad flame sensor when flame sensor doesnt sense flame it will shut off after 7 seconds

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Automatic igniter will not activate no gas at piolet orofice model b-055b-en

make sure gas supply is on and you have adequate gas pressure make sure you have good flow a plugged filter will not open the pressure switch make sure ignitor is not shorted or open should ohm out at 78 ohms

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Oil pressure guage not registering

The oil pressure gauge on a 2004 WJ doesn t really show the pressure, but it will go to a preset value when pressure is ok, or it will stay at o PSI. So you need a pressure switch on this jeep and not a pressure sending unit. If the right unit is installed, then or the pressure indicator is faulty, or wiring. Do a test of the instrument panel to see if the indicator works: ignition switch in off, press the odometer reset button and now switch ignition in run. Instrument panel will start a self test, all lights will come on and all meters will go full scale and return to normal.

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Lo error on hayward pool heater

"LO" is simply informing you that the Heater is not sensing proper water flow through it! A Flow Problem.
A special sensor, called a pressure switch is this source. But... That does not mean it is bad - No, it is in most cases just doing its job!
Most common reason - Dirty Filter.
A good cleaning of the cartridges, or maybe a breakdown and recharge of a DE Filter, or a good cleansing backwash of your sand filter, will remedy this situation.
Or... Check for any OTHER reason or situations water flow may be reduced through the heater:
  • enough water in pool or spa?
  • If you have a weir gate in skimmer, is it stuck in the UP position?
  • Are any valves closed?
  • Do you have a bypass valve at the heater?
    • If open, this will reduce the amount of water going thru heater, close it to the point, LO goes away.
  • Could be debris in front of Pressure Switch, in the copper tubing
    • Unscrew and remove pressure switch, turn pump on. But first, align end of tube so that when water squirts out it will shoot out from heater and not onto electronic heater components!
  • If all above is good, you may have failed pressure switch?
  • Etc
Good Luck - hope this helped.

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