Water pump burps every 35 to 40 seconds for 2 to 3 seconds

[dfm]

6 weeks ago ,when I had the city water connected ,my fresh water tank filled . When I turned on the water pump,water came out of the gravity fill spout. So assuming the check valve at the city water connection had failed I replaced it. Didn't use the trailer since then and now when I filled the water tank,turn the pump on to pressurize the system every fawcett works fine but every 30-40 seconds the pump burps for 2-3 seconds. I have checked every connection I can find inside the trailer and all are dry.I have not taken down the plastic liner on the bottom of the trailer to look for exterior line leaks yet.
Previously when hooked to city water and with the tank filled I could turn on the pump in order to increase waTer pressure if needed,although I seldom did. NOW the water pump will not come on when connected to city water if I turn the pump on and open a fawcett/shower.
I installed the present flojet "4406-143"water pump 7 months ago.Pump is still on warranty . I am thinking that because the water pump burps so frequently and for such a short time that I have a faulty check valve in the pump. When I disconnect the outflow side of the pump and cap it with a plug the pump burps even more frequently and for a shorter time.

Anyone have any comments/help?? What to try next? I took the pump to the dealer and when they capped the outflow it did not burp.I am going to cap the outflow again today to see if it burps when installed in my trailer.

UPDATE....

JUST capped the outflow again while the pump was in the trailer and it burps continuosly for 1second every second! Does this mean the check valve in the pump is faulty and the pump needs to be replaced?/

[Happy_Waver]

If its not a leak it could be an air bubble. I know on my old Thor unit I had to go in sequence from back to front to remove them all. Outside shower always caused problems

[gaugeair]

I had the same problem with my old pump. I was connected to city water and after a little while the water started coming out of the fresh water fill. Pump worked fine it was just the check valve. I installed one of these and it worked just fine. Very easy to install. Cut the 1/2" pex on the outlet side of the pump and push this on.

Link

[dfm]

--------------------------------------------------------------------------------
.2 GPM should not cause a problem. Is your suction flooded? Or do you have to draft? If suction is flooded you will have a leak between the tank and pump. If it is a draft you will usually have bubbles in the pump discharge water. This is usually more visable in the hot water side. Check a faucet with out a screen. Put a guage on a discharge line and see what is actully happening. A guage will let you know if you have a pump discharge valve is leaking as well as your pressure switch on/off setting. Differential pressure.

Not sure I understand what you mean by

"" Or do you have to draft? ""

Do you mean a leak on the supply side between the pump and the tank?

[2oldman]

dfm wrote:
JUST capped the outflow again while the pump was in the trailer and it burps continuosly for 1second every second! Does this mean the check valve in the pump is faulty and the pump needs to be replaced?/

Sounds like it.

[Kjun]

.2 GPM should not cause a problem. Is your suction flooded? Or do you have to draft? If suction is flooded you will have a leak between the tank and pump. If it is a draft you will usually have bubbles in the pump discharge water. This is usually more visable in the hot water side. Check a faucet with out a screen. Put a guage on a discharge line and see what is actully happening. A guage will let you know if you have a pump discharge valve is leaking as well as your pressure switch on/off setting. Differential pressure.

[Capt_RonB]

Usually the pump cycling like that indicates a leak. If all the connections you checked are dry, then it's likely a suction side leak such that the leak can suck air but oozes no water. Pressure side leaks are always wet.

Hope you find it. Usually there aren't too many suction side joints. I'd try disassembling and resealing each connection on that side of the pump. Sometimes Teflon tape doesn't cut it on plastic threads so I'd try a paste type joint compound. Sometimes the 'hand tight' plastic connections need a little help from the channel locks. An extra 1/4 turn on the right fitting may solve the problem.:)

[dfm]

That's what I was thinking,that maybe the pressure switch was fouled. It worked for the last 7 months. The pump is 3.2 gpm at 35 psi. The previous shurflow pump was 3gpm At 35 psi.

[Kjun]

It sounds to me like you have a pressure switch problem. Is the pressure switch built into the pump? The low pressure on is set to close to the high pressure off. The pump is cycling. Pluging the outlet at the pump only makes this worse. Most plumbing systems have enough piping length to act as a accumulator. Is the new pump any larger in voluum than the old pump?

[naturist]

there are check valves in the water pump and it sounds like they have failed and are leaking. Dunno what pump you have, you might be able to replace just the check valves (one each, intake and output, but do both), or you might have to replace the entire pump.