What happened after I replaced the leaking pressure switch, the heater now cycles on but goes out in a couple of seconds.

you can try replacing the a/c cycling switch. but if pressure is going up and down it sounds as if there's a leak .did you try stop leak when you tried recharging it?

Hello, usually this happens when the pressure switch remains open, this could be due to a blocked flue pipe, water inside the tube between inducer motor and pressure switch, or the switch itself is going bad. Condensation can form and leak back to the pressure switch through the tubing and causing an intermittent problem with the inducer motor running continuously

Hi dear.Please follow this if you can do it,other wise call service department.I hope that solves your problem.Thanks. F14
Water intake fault: Heater pressure switch
Cause:
Heater pressure switch B1/13 defective.
Remedy:
1. Check the heater pressure switch.
2. Check the connection plug and wiring harness.
3. Replace the heater pressure switch, if necessary.
Cause:
Circulation pump inoperative. Circulation pressure too low (no pressure at
heater pressure switch). Pump may be blocked by foreign objects.
Remedy:
1. Check the circulation pump for foreign objects.
2. Check the circulation pump capacitor.

check the thermal coupling for the pilot light. if it goes out it will shut down gas supply, its a safety feature to put out pilot light if the thermal coupling is bad. to prevent gas from leaking and causeing a fire. check coupling.

Hi,
Here are a couple of tips that I wrote that tell you how to troubleshoot aTorpedo or Reddy heater...

Reddy Heater - Troubleshooting Torpedo Heaters Torpedo Heater Pump Pressure Adjustment
heatman101

You're most likely getting a pressure wave (spike) that is generating momentary flow across the flow sensor. The heater is registering this "instant" flow and beginning its firing sequence. Once the flow dissipates, the unit then goes into a purge cycle. I'd recommend having your water pressure tested to make sure it isn't abnormally high (above 60 psi) or abnormally low (below 30 psi). Assuming the pressure is normal, you can use a pressure reducing valve or pressure regulator to absorb the spikes and stop the unit from cycling.

insert on hot water and see if open or close than on cold water and must reverse from hot. if nothing happen replace

An engine temperature sensor that halfway works could be telling the ECM that the engine is already warm but the problem is more likely to be a fuel pressure problem or both. A fuel pressure leak-back within the system or lack of initial prime cycle ( the prime cycle is activated for about 3-5 seconds when the key is turned to the on position regardless of whether you start the engine or not.) To check this; have someone listen at the fuel tank (unless your pump is noisy, and most of them are) and when you cycle the ignition all the way off for about 5 seconds and then to the on position ---WITHOUT TRYING TO START IT-- you will hear the pump make a buzzing sound for 3 to 5 seconds each time you cycle the key off for about 5 sec and on for 5 seconds. If you can hear the pump cycle while doing this test then try cycling 2 times before starting and if it starts immediately each time then you will probably need to replace the pump or regulator depending on a couple other tests to find out which one. If you have very high mileage and cylinder wear then it may also take a little longer to start. it should never take more than about 4 seconds to start and 2 to 3 is even better. look into those couple things and any questions or additional information --just ask