Water Pressure Blow-Off

norwood

Question-Normal? 2015 320 Max Q (no wet bath). We are camping without water hookups. When using water pump it sometimes discharges water pressure from (Alde) relief valve under floor when pump stops. Not every time but often enough to get my attention. Just a burst, not continuous. Is this normal? We have only dry camped once before and didn’t have this experience.

ScottG

I've heard of that happening with shore water--usually when someone has forgotten to use a pressure regulator. That is normal as the valve is designed to protect the system from excess pressure.

However, the pump is comparatively wimpy, and I wouldn't expect it to create enough pressure to open the relief valve. I've never noticed it on mine--though that doesn't mean it hasn't happened.

You may have a faulty relief valve. Seems there have been a couple of those reported over the years.

Sharon_is_SAM

Interesting that it discharges just as the pump stops.  There must be a momentary excess back pressure that pops the pressure relief valve.  I agree with Scott - need to replace that valve.  Does it happen if you run cold water only?  Is the pump making any different noises?  

klenger

There may be a setting on the pump to reduce the pressure.

norwood

Thanks for the replies. @Sharon_is_SAM no, it releases on hot and cold water. Hard to tell if the pump is making any new noises as it always sounds like it’s gonna vibrate off it’s mounts. Which valve do you suspect? We are without cell service for the rest of the week unless we are out of the campground hiking or biking (like now).

Sharon_is_SAM

@norwood,  I suspect it is the yellow flapper valve (Alde pressure relief valve) that is designed to open and drain through the floor in the event of excess water pressure.  Do you have one of those?  

ChanW

Yeah I was trying to think 'what pressure relief valve'? But ours (early 2014) doesn't have one. 

I wonder when they started putting the yellow handled one in.

Can you get us a photo @norwood?

Sharon_is_SAM

@Chan, do you have any Alde discharge vent/valve or just tge hot and cold water drains?

ScottG

@norwood, this is the valve being discussed. The valve is in the cold water supply to the Alde, and doubles as a drain for the Alde. Some sort of spring tension allows the valve to open a bit when the pressure in the lines exceeds a certain amount. To open it manually, you flip the yellow lever to the vertical (perpendicular) position.

@ChanW, I have one in my Dec 2014 built T@B, so they must have been added between late 2014 and early 2015 models.

ChanW

@Sharon_is_SAM, I think the hot output (the red one in the lower left in @ScottG's photo) is a pressure relief, or I always assumed, with its drain tube. That's all we have on ours.

Sharon_is_SAM

@ChanW, so it would discharge through the clear hose then.

ChanW

Yeah, it seems to make sense. I don't know what else that tube could be for...
Sharon_is_SAM said:

@ChanW, so it would discharge through the clear hose then.

ScottG

I'm not absolutely certain either, but I agree that the red doohickey on the Alde output is also a pressure relief device.

norwood

A little more data: The water tank was near empty so filled it up and the blow-off issue has not returned. Now need to work on the noisy water pump. 

ScottG

It's possible the valve had some crud in it and temporarily wasn't seating properly. It may have just worked itself out, but I would continue to keep an eye on it for a bit.

I'm glad the problem has stopped, but I can't see any possible connection to how full the water tank is.