Water heater check valve location

j52wf · 05-06-2021, 12:59 PM

I have a 2007 257sr. While sanitizing water system, pump would activate intermittently. Found no visible leaks, but water started to slowly drain from my empty HW heater. I have a one valve bypass system. I am thinking the upper check valve may be the culprit. Could someone point out to me exactly where that might be? And how to fix/replace it. Thanks.

**JohnB** · 05-07-2021, 09:52 AM

Hi Jim,

Here is check valve you are talking about. It on the top back of the water heater. It is brass screwed in directly to the heater. Looks like this.

Here is a replacement for it. I bought them here the last time as they were cheaper at that time, pre-covid. You can look at other places for the same check.
https://www.etrailer.com/s.aspx?qry=...22+MPT+-+Brass

Valterra Check Valve for RV Fresh Water Systems - Dual 1/2" MPT - Brass - P23415LFVP

And yes, there have been times they that water heater check leaks backwards into an empty water tank as the O ring seal gets sediment on it or it falls off the groove. This shows up often when you winterize and antifreeze drips back into the water heater as the system cannot build pressure and the water heater is empty on purpose.

If you are sanitizing the camper, by chance are you be bypassing the water heater and have an empty water heater? Do you sanitize the water heater?

The pump cycling with "no leaks" visible with a "full water heater" normally points to a leak in the fresh water pump. Water drains back through the pump, then back into the fresh tank and you will never see any water. If you want to test that it is the pump, fill the entire system, water heater too, and pressurize up the system. If the pump keeps burping every so many minutes and you are positive there are no water leaks, then it points to the check valve inside the pump.

You can also hook up city water and if the fresh tank overflows after an hour or more or keeps gaining water in the fresh tank, the only way it can get water in the fresh tank in this way if backwards through that check inside the water pump.

Hope this helps and let us know how you make out.

John

j52wf · 05-07-2021, 06:18 PM

Hi John,
Good to hear from you. Yes, I am bypassing the water heater on purpose. It is empty. I do not sanitize the water heater. There is definitely a slight backflow into the water heater with the pump on. It comes out of the drain hose on the heater. I will investigate the pump check valve when I am on city water over the Memorial Day weekend. It wouldn't surprise me that both need to be replaced. I am looking forward to a busy camping season this year. 5 nights Dover, DE for the races, then 5 nights at Cherrystone, VA (with the Mrs.) over Memorial Day. 9 nights in Nashville for sightseeing and some races (also with the Mrs.). Then 4 nights at Pocono for more races. And that's just May and June! We are all fully vaccinated and ready to go! This will probably be my last full season with this Sunline. After my wife retires next year, we are going to look at something substantially newer for some longer trips. Hope all is well with you and the family. Say "hi" to Ben.

**JohnB** · 05-08-2021, 04:00 PM

Hi Jim,

The check valve for the water pump is inside the pump and part of the pump. It is not external like the water heater. If it does leak, it may be a piece of dirt stirred up
and stuck in it or it could be a possibly scratch in the valve seat. They do offer pump rebuild kits that would replace the check, or a whole new pump. The price between the two may not be that much.

All is well with us and the family. We are all now fully vaccinated as well. We have been out camping twice already this year. Next up is memorial day weekend and a little longer. Our old normal long multi state Sunline road trip is on hold again this year, due to Covid and not having all the reservations in 9 months plus in advance. But we will camp more here in Ohio, so still camping, just not as much as we wanted to.

Take care

John

j52wf · 05-08-2021, 07:37 PM

I hooked up to city water today to do a better flush of the lines and the HW heater. Happy to say that no water backed up into the FW holding tank, so that check valve checks out. Lol.

**JohnB** · 05-08-2021, 09:14 PM

Great! The pump is good and holding.