Low pressure and flow cold only

[doodle]

OK well we have now taken delivery of the 2012 Tiffin Allegro Red 38QRA that I asked questions on before.  We were sanitizing the system and during the flushing we noticed low pressure and flow on the cold water side effecting all the systems.  When you open any faucet to the cold side (or toilet) the pressure and flow starts off strong and then diminishes to a trickle.  Shut off the water for a minute, and the pressure re-builds, open again and it starts off strong and slows to a trickle.  Move the faucet to the hot side and the flow is normal.  This happens when on City or Pump.  When using the pump and drawing cold water, the pump cycles on and off,  but when drawing hot water, the pump runs constantly while the faucet is open.

I have opened the low point drains with the City Water on and get the same result at the low point drains: Hot is strong and cold starts strong and slows to a trickle.
Checked the city water connection and hose for debris, checked all shutoffs I can locate, looked for any kinks in the pipes (cannot see behind the wet bay panel),  checked every faucet and drain with the same result.

Any thoughts? Am I missing something that could be on the cold side behind the wet bay after the split to the hot water? Thanks so much for your help!

 

[Gary RV_Wizard]

Did you leave a valve in the tank fill position, maybe?

Since it acts the same whether pump or city, you can rule out pump and city inlet as the problem areas. I suspect the hot acts better simply because of the pressure reservoir in the heater tank. It gets it water from the cold side, so can't stay better for very long.

 

[doodle]

Thanks Gary.  Valve is not in tank fill position.  The cold water flow diminishes within 5 seconds of turning it on.  I've let the hot water run for several minutes and it remains strong. How long would it have to run before diminishing like you suspect it would? This happens at all the sinks as well as the low point drains. 

 

[doodle]

After having some dinner, went back out to try and brainstorm some more, and the cold water flow is now just a drip. Plan to call tiffin tomorrow, but if anyone has any ideas in the meantime, we'd love to hear them!

 

[mhbell]

If you have a water heater bypass, have you checked to see if the valves are in the proper position?
Mel

 

[doodle]

Hi Mel.  Thank you for your question.  Yes there is a bypass and it was in correct position.  But I tried it in both positions in case it was installed backwards. 

 

[grashley]

I do not know how units are normally plumbed, but it sounds like a MAJOR blockage (almost closed valve, collapsed pipe) in the cold water system, after the point the city water system and coach pump system unite.  It may be after the tee to the hot water tank.  Since it affects all cold water, it must be very close to the input end of the system before any tees or manifolds send water to different locations.  Easy to talk.  Hard to find.  Good Luck!

 

[Chuck and Lori]

Could be the main water filter is plugged.  Some motor homes the hot water bypass the filter, only the cold goes through it.  If yours is like that, the cold would not flow but the hot water flow would be fine.  Easy to find out, turn off water at post, open filter canister, remove filer, turn on water and check flow.  Hope it's something easy to fix, sometimes you get lucky.

Thanks  Chuck

 

[doodle]

Chuck, you are spot on!!!  Hi All.  Donna here updating for Matt.  It appears the problem was the whole house water filter...high filtration, low flow. He decided to remove the top panel in the wet bay to try and get a look at the plumbing.  Too small an area for his head to get a good view, but he was able to fit our small video camera back there and took a video of the pipes which he then watched on the computer.  No sign of any pinches, crimps or collapsed pipes.  What he did notice, however, is that the water filter appears to be on the cold line after the split to the hot water heater.  He removed the filter, and water is flowing properly again. Glad it was such an easy fix!

 

[Rene T]

Anyone know why the whole house wouldn't be filtered?  That doen't make sense to me.

 

[TipTopRV]

We have 2008 Tiffin Phaeton and around the same time we replaced the toilet, the cold water slowed flow. We could not figure it out for the longest time ... and worst of all the brand new toilet hardly flushed at all!! We couldn't figure out if the toilet install could have had something to do with it!?

But nope...

The water filter was totally the problem!~
Took it out and voila!

;D : ??? 8)

THANK YOU!

 

[Alfa38User]

Anyone know why the whole house wouldn't be filtered?  That doen't make sense to me.

Many trailers (at least) have a built-in (charcoal) filter that feeds only a water spigot in the galley and the refrigerator ice maker (when equipped). Some are small in line filters, others are the "whole house" style filters like mine. I added a more course whole house filter outside in the hose feeding the trailer.