Water flow out the tank overflow when on mains in Jayco

OutbackMK · Senior Member

Water flow out the tank overflow when on mains in Jayco

Cupie · Guru

OutbackMK wrote:
As the above suggests most Jayco vans suffer this fate. Usual answer is new pump $180 thankyou.
Got a part number (Coast to Coast) to order through an agent.
800-00162 $33 This is the rubber diaphragm/valve replacement part takes about 5 minutes to install.
Hope this saves someone some hard earned, hope to pick up one for my van when I hit Townsville next week.

I must be one of the lucky ones.

Haven't had this problem in 20yrs with my Jayco. Nor has my Daughter with her Jayco over her 5yrs ownership.

Perhaps an issue with some of the newer models.

I'll make a note of the part number, just in case.

Thanks for sharing.

iana · Guru

I might suggest that this is not a pump fault but the result of a problem up stream in the system. I have been doing some work on the water system of our van, looking for water flow/pressure loss. Just after the mains water connection, past a course filter and a NRV, there is a pressure limiting valve, this valve limits the maximum pressure in the system when on mains water to 51psi. Inside this valve it looks like there are sliding sleeves etc probably of a close fit, seals etc., I haven't dismantled one only seen a cross section drawing. But it is my gut feeling that since this valve is mounted on its side, and the water coming in is not well filtered, then sand and dirt will soon block up the mechanism and stop it from working.
If this occurs, then the system could get full mains water pressure, and I doubt the pump is designed to handle that back pressure that main water supplies could get up to. Now this is only my theory, as my work on the system was because of low flow at the shower head when on mains supply, our pump has not played up yet, except for noise.

PeterD · Guru

Go to this page. Scroll down to "4) Adding mains pressure and hot water" and look at the diagram. You will note a non-return valve between the pump and the main reticulation system. The 12 V pumps are not really made to suffer the effects of mains pressure on their outlet side. Even with a pressure reducer on the mains inlet the system pressure can be higher than the pumps working pressure. This is what is breaking down the valves in the pump and allowing water to flow back through the pump and overfill the tank(s.)

Jayco in their wisdom cut corners and do not fit that non-return valve. Rather than waiting for the pump to break down I would suggest you take it upon yourself and correct this poor workmanship. Fit a non-return valve at your convenience rather than have the pump fail an an inconvenient time. This particularly needs to be done if you mainly frequent caravan parks.

iana · Guru

Hmm had a read, but if you go to paragraph 7 "The Shurflo incorporates its own non-return value, so the separate one shown in diagram would not be required ". I would still be looking at putting better filtration before the " Pressure limiting valve", and also stripping it down at intervals to make sure the internals are not seized.

PeterD · Guru

So why are so many of their pumps failing? At any rate, if the pumps inbuilt non-return valve fails then incorporating an external one would be cheaper than replacing the pump.

iana · Guru

Peter, I am talking about a "PRESSURE LIMITING VALVE" not a "pressure reducing valve", this device limits the system pressure to 51psi. The pump can work up to pressures of 55psi, and the bypass valve can be adjusted up to 62psi. As it is my pump is set at 45psi, however the pump is designed to handle those pressures. I am saying that if the PRESSURE LIMITING valve stops working, then mains pressure from the town is through the system and this pressure could be way higher than the pump and the system piping is designed to handle.
Regardless of whether another NRV is fitted or not, other appliances such as the hot water service, pipe work etc. may not be able to cope with town mains pressure. So like I said in my first post, the culprit for all of these things could be the pressure limiting valve.
Further on Friday I went to Jayco and brought a new "Pressure Limiting Valve", and they had a stack of them on the shelf, which suggests to me, that they are a high use, or replacement item.

Cupie · Guru

PeterD wrote:
So why are so many of their pumps failing? At any rate, if the pumps inbuilt non-return valve fails then incorporating an external one would be cheaper than replacing the pump.

So why are so many of their pumps failing?

Is this so? What is the evidence?

BTW mine has not failed despite always using CPs. Perhaps it has the external device fitted.

TheHeaths · Guru

Well, adding my 10 cents worth.

We had this issue intermittently this time last year when we were travelling through WA. The tanks would be empty, then over a period of time while in CP's connected to water, they would fill and eventually overflow back out of the vans 2 fill points.

I fixed the issue (tanks filling and overflowing, not necessarily the root cause), by putting a Non Return Valve into the suction lines for the tanks, immediately above the joining valve where they come into the van. Incidentally we have a 2012 Jayco StarCraft, 21.66-3 model.

This has prevented the tanks filling at all, does not seem to have created any problems for the pump, allows the water to be drawn from the tanks when necessary by the pump, and was cheap (about $10 for the small NRV).

I am happy with the outcome, and it may suit your fix.

-- Edited by TheHeaths on Sunday 13th of August 2017 02:37:39 PM

PeterD · Guru

Cupie wrote:
PeterD wrote:
So why are so many of their pumps failing? At any rate, if the pumps inbuilt non-return valve fails then incorporating an external one would be cheaper than replacing the pump.
So why are so many of their pumps failing?
Is this so? What is the evidence?
BTW mine has not failed despite always using CPs. Perhaps it has the external device fitted.

My evidence is the number of times the subject comes up from Jayco owners. It has been coming up in the different forums at least twice a year for the last few years. It is one of the more frequently occurring subjects.

PeterD · Guru

It did not take long for the next one did it? - Mains water pressure fill up front water tank

I suppose you reckon I arranged this one as a plant.

PeterD · Guru

iana wrote:
Hmm had a read, but if you go to paragraph 7 "The Shurflo incorporates its own non-return value, so the separate one shown in diagram would not be required ".

When I first answered this I did not pick up that they were no referring to a Shurflo pump. If you go back to that article and click on the heading of parra 7 you will see what they were talking about. Surflo also make water inlets. If you have one of their inlets you do not need the other non-return valve.

OutbackMK · Senior Member

Well I asked to order the replacement valve from Jayco and was told they had never ordered one in the past, for most customers they replace the pump or add a non-return valve. As the non-return valve was ex stock and the same price as the replacement rubber I went with the valve, They said that the disassembly of the pump took longer than the nip and tuck of adding the extra valve. (they said that many installs can be done under the van) mine however because of the plumbing needs to be done at the pump under the bed and means cutting up more tubing to make room for the valve between the pump outlet and the "T" piece to the high pressure side from the mains pressure supply.
OH well that's sorted and a new problem arises... Noise when connected to the mains, I will outline the fix for this under a separate post.

-- Edited by OutbackMK on Monday 21st of August 2017 10:12:28 PM