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Topic: Hot water gets hotter and cooler while taking a shower (Read 1240 times) previous topic - next topic

Re: Hot water gets hotter and cooler while taking a shower

Reply #25 –
Thanks Richard, Rudy and Scott.  It really is as simple as it appears.  I figured for sure there was something I could break when taking it apart.  So far so good.  Replaced the valve and reinstalled the burner.  Letting it heat up now.

Also did Pyolet's "turn the tempering valve" trick a few times while it was easy to access.  Looks like it's only about 1 turn from closed to open...is that right?  Mine is set at maybe 3 o'clock from fully in (clockwise) about 5-6 o'clock and fully open about 1 turn counter-clockwise (6 o'clock).
Keith
2003 U320 38' #6197

Re: Hot water gets hotter and cooler while taking a shower

Reply #26 –
Ran the AH last night until it got up to temp and shut off.  No leaks.  Checked the temp at the kitchen faucet, 121*F, so it looks like I'm good there too.

Slightly off topic, but still related to the AH, while it was hot I decided to test all zones for heating since we're eventually going to get some cooler days (still in the low 80's here - it's NOVEMBER!) at some point. 
    • Zone 2 - bedroom, has one heat exchanger under the bed and works fine.
    • Bathroom has it's own t-state and works fine.  One heat exchanger with a branch that feeds the toilet room.
    • Zone 1 - front living area.  There are two heat exchangers, one under the stove and one in the pedastal for the table.  Both work good.  I also had air coming out of the dash vents, but ambient temp only.

Is there another heat exchanger in the dash?  If so, is there any reason it would not get heat while the other exchangers in the front area do?
Keith
2003 U320 38' #6197

Re: Hot water gets hotter and cooler while taking a shower

Reply #27 –
Quote from: WS6_Keith –
1. Is there another heat exchanger in the dash? 
2. If so, is there any reason it would not get heat while the other exchangers in the front area do?

1 Yes
2 Not that I an think of.  Ours takes a few minutes (almost when it cycles off) for the heat to come out. I thought it was due to the radiator in the dash is down stream of the primary as they are in series.

Mike

Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Hot water gets hotter and cooler while taking a shower

Reply #28 –
Quote from: Pamela & Mike –
1 Yes
2 Not that I an think of.  Ours takes a few minutes (almost when it cycles off) for the heat to come out. I thought it was due to the radiator in the dash is down stream of the primary as they are in series.
Mike
Maybe I just didn't give it long enough.  Maybe ran it for 2 minutes in each zone.  I'll give it a bit more time next time.  Thanks Mike!
Keith
2003 U320 38' #6197

Re: Hot water gets hotter and cooler while taking a shower

Reply #29 –
Quote from: WS6_Keith –
Maybe I just didn't give it long enough.  Maybe ran it for 2 minutes in each zone.  I'll give it a bit more time next time.  Thanks Mike!

My 96 U320 has three heat exchangers in the dash:

 AC evaporator
 Coach heat exchangers, 1 for engine supplied heat and 1 AquaHot supplied heat.
Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Hot water gets hotter and cooler while taking a shower

Reply #30 –
Quote from: WS6_Keith –
This past weekend I noticed while taking a shower that the hot water seems to come and go a little bit, like not enough water can get through the aqua hot.  Anyone ever experienced this before?

I've been thinking about this.  If you are using your water pump and have an accumulator then the water pressure in your system varies as the pump cycles on and off.  The OEM shower valve controls the rate of flow and the relative mix of hot and cold water. It is not an automatic mixing valve that controls the mix of hot and cold to maintain a set temperature.  You could change out the whole shower valve to do that but then with most of these valves you have no volume control.

The AH mixing valve is more automatic,  mixing cold water and the AH hot water (it could be as much as 180°] so that hot water coming out of the mixing valve is no more than 120°. 

At the shower you mix hot and cold water based on where you set the knob.  If the pressure varies in the water system and there is more resistance in the hot water side then at lower system pressure less hot water will mix with cold water and when the pressure goes up more hot water will mix.  If the total volume setting is low this temperature variation should seem less.

The AH mixing valve may need replacing but the hot side is whatever comes out of it.  The more likely place for a hot water side restriction is at the Manabloc or the shower valve itself.  Make sure the shower valve is clean and all of the screens etc in the shower head and hose are free of crud.

We recently did the vinegar soak and flush.  Lots of blue stuff coming out, that is mostly vinegar reacting to the copper.  And lots of small bits of stuff.  After you are done with that check all of the screens again. The screen at the vacuum breaker on the shower hose was completely clogged up, no water got through.  I called Moen and the sent me 2 new screens free of charge.

Check the easy stuff first.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Hot water gets hotter and cooler while taking a shower

Reply #31 –
Good thoughts Roger.  I did the vinegar wash two weeks ago, so I hope that flushed out system and maybe these issues will no longer be present.  I had removed the shower head from the hose for this.  I also did the AH tempering valve full closed/full open cycling a few times while I had the burner out, and reset for 121*F at the kitchen sink.  Hoping to get away this weekend to give it a test run.
Keith
2003 U320 38' #6197
 

Re: Hot water gets hotter and cooler while taking a shower

Reply #32 –
Between moving the tempering valve and the vinegar treatment, it seems to have eliminated the surging hot water issue.
Keith
2003 U320 38' #6197