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Topic: Why is my cold water hot? (Read 1708 times) previous topic - next topic

Why is my cold water hot?

We're camping at a COE park a couple of miles from our house, trying to familiarize ourselves with our new-to-us coach.  We find that our cold water is hot.  It is not as hot as the hot water, but it is still hot.  I've tried both diesel and the electric modes on the aquahot, and the water is still hot.  What have I got set wrong?

This will not be the only dumb question I ask this week!

Glen
Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099

Re: Why is my cold water hot?

Reply #1 –
Glen,

If you have just arrived at your site, our cold water may be a little warm in warmer weather. Or maybe your AH mixing valve needs to be rotated a few times (to break up a stuck position). It is hard to reach and it is directly below the Webasto burner. Remember it's original position.
Jim
Jim Frerichs
2002 U320 42'

Re: Why is my cold water hot?

Reply #2 –
Trust me when I tell you there are no dumb questions.

Sometimes we give dumb answers and then realize it later.

As for the hot water I'm thinking on that one. Electric or diesel wouldn't matter. 
Rick & Rhonda
2003 U320 4220  Build #6199
Was
91 36' GV 300 Caterpillar, 92 40' U280 300 Cummins, 97 36' U295 300 Cummins, 2002
U320 450 Cummins
(Guess we're hooked)

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Re: Why is my cold water hot?

Reply #3 –
Glen,

Are you hooked up to the campground spigot getting water?  If so is your hose out in the sun?  This can cause some real good solar heating and can run hot water a lot longer than you think till it has time to cool off the hose. This is my first WAG.
 
If you are on onboard water I will have to think about that.

We were wondering what COE park are you at that is close to Colmesneil?

Pamela & Mike
Pamela & Mike 97 U 320

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

Re: Why is my cold water hot?

Reply #4 –
I find that when I leave the aquahot on electric overnight the first burst of cold water out of hte bathroom sink will be warm.  I think any pipes that run above the aquahot get heated.  Unfortunately the aquahots seem to be a bit inefficient.  It does a great job of keeping my bays from freezing in the winter though!

Re: Why is my cold water hot?

Reply #5 –
I will try the mixing valve.  That sounds logical.

I tried the electric because it seemed like the Aquahot was staying on a lot.  Since I'm trying to learn some of the ins and outs of the coach I'll try anything once or twice.  I was on the onboard water tank, as I am a little bit leery of relying on the water hose supply.

I'm at Magnolia Ridge, on Stienhagen Lake about halfway between Jasper and Woodville.
http://www.recreation.gov/camping/magnolia-ridge/r/campgroundDetails.do?contractCode=NRSO&parkId=71279

Thanks for the help.

Glen
Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099

Re: Why is my cold water hot?

Reply #6 –
Quote from: Glockjock –
I tried the electric because it seemed like the Aquahot was staying on a lot.  Since I'm trying to learn some of the ins and outs of the coach I'll try anything once or twice.  I was on the onboard water tank

Glen - what's the dial thermostat set to in your fresh water bay?  Wondering if your basement zone is set to run the heat exchangers unnecessarily.  On our '03 it's a simple black knob with a brass plate mounted on the front of the Manabloc cover.  If it's set for an unusually high temperature, it could be one of the reasons you hear the AH coming on a lot.  Also listen for the heat exchanger fans in that and the utility bay to see if they're running.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Why is my cold water hot?

Reply #7 –
Quote from: Michelle –
Glen - what's the dial thermostat set to in your fresh water bay?  Wondering if your basement zone is set to run the heat exchangers unnecessarily.  On our '03 it's a simple black knob with a brass plate mounted on the front of the Manabloc cover.  If it's set for an unusually high temperature, it could be one of the reasons you hear the AH coming on a lot.  Also listen for the heat exchanger fans in that and the utility bay to see if they're running.

Very perceptive, Michelle.  Stewart had shown me that temperature set knob during a brief walkthrough when we bought the coach from MOT.  He recommended setting it at about 40º to 45º F to prevent freezing.  There was a lot of heat in that area and in the bays so I turned it down all the way.  That didn't change anything, though.  That thermostat may or may not be functioning correctly.

I am back home now under my RV shed.  I'll now go try to find the mixing valve that Jim mentioned.  I'll eliminate one thing at a time. Gotta learn it sometime! :)  Anybody know how to get to this valve?  It may be intuitive when I get there, but it never hurts to ask.

Pam and Mike, you may be wondering why I said the COE park is near my home in Colmesneil.  It is just that my mailing address is says Colmesneil, even though my physical location is only a mile or so from Stienhagen Lake.

Glen
Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099

Re: Why is my cold water hot?

Reply #8 –
Quote from: Glockjock –
Very perceptive, Michelle.  Stewart had shown me that temperature set knob during a brief walkthrough when we bought the coach from MOT.  He recommended setting it at about 40º to 45º F to prevent freezing.  There was a lot of heat in that area and in the bays so I turned it down all the way.  That didn't change anything, though.  That thermostat may or may not be functioning correctly

Glen - check the zone valves on the AquaHot.  IIRC the basement one is shared with the bathroom (controls are independent thermostats, but I seem to recall the plumbing is shared).  I'm wondering if that zone valve is stuck open (usually they stick closed, but you never know - we had one in a house with hot water baseboard heating stick open).  With all the zones turned off (but AH on), if you feel one pumping hot water through, that could be it.

It could also be that the knob for the thermostat is misaligned to the control shaft, and what you think is 40-45 is actually higher.  But then when you turned it down all the way (ignoring where it was pointing) it should have changed the behavior.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Why is my cold water hot?

Reply #9 –
Quote from: Jim Frerichs –
Or maybe your AH mixing valve needs to be rotated a few times (to break up a stuck position).

Jim - why would the AH mixing valve impact cold water temperature?  I can see it affecting the temperature of the hot water (since it's what controls the temperature of the domestic hot water), but the domestic cold water should be separate since I believe cold is only used by the AH mixing valve to temper the domestic hot water.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Why is my cold water hot?

Reply #10 –
Glen,

My wife and I arrived in Livingston this afternoon.  We'll be staying a week.  I'd be happy to help if you need a hand.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Why is my cold water hot?

Reply #11 –
Michelle,

Normally it would not bleed backward to the cold side, but maybe it or a check valve is faulty.

Jim
Jim Frerichs
2002 U320 42'

Re: Why is my cold water hot?

Reply #12 –
I've been thinking about this since you posted it....

I know you've owned coaches before but I'm going to start with the obvious.  If you are pulling water from the fresh water tank, your "cold water" is only going to be as cold as the water in the tank.  For newbies like us, this obvious fact was a surprise our first summer having the coach.  The water in the tank can get surprisingly warm.

I suppose your A/H could be heating the bay above it's 50F max.  A couple of things to check here.  First if you open the door where the plumbing manifold is and look down to the right you should see the A/H heat exchanger.  Is it warm or hot?  It's been in the 80s here there is no reason this should be coming on.  If it's warm, I would make sure the thermostat in the bedroom is switched to off then give it while to cool down and check it again.  If it stays hot, it could be a stuck stir pump, too.  When you have the cover off the A/H you should see three pumps toward the top.  Furthest to the passenger side is the front zone, I assume the middle is the bath/bay, but it could be the furthest to the drivers side.

Unless there has been some creative re-plumbing I can't imagine how you could be getting a mixture of "hot" and "cold" on the cold side of the plumbing system.  I keep thinking maybe there is some sort of re-circulator that's stuck on.

So the questions for you are:
How hot is the cold water?  Is it the same temp at all three taps?  If you open the tap full cold for 5 minutes does it get colder?
Seems the best way to get a fairly accurate temp is to fill a cup and then use an instant read type kitchen thermometer.  Trying to use an IR gun doesn't seem to give very accurate readings.

As far as the mixing valve:
I don't think that has anything to do with this issue, but it's always a good idea to "exercise" it, and make sure it is set correctly.  It's very hard to reach but you should be able to get one to two fingers on it from under the Wesbasco burner.  Try to turn it fully one way then fully the other way.  It really should turn with just one or two fingers.  If it just spins it's probably time to replace the guts.  If it's stuck it maybe time for new guts.  If it turns easily each direction, then you just need to set it correctly.

To set it, with A/H up to temp, and diesel turned on, run hot water at outside faucet for about 2-3 minutes, then fill up a cup and test the temp.  Should be 120F.  If hotter or colder, move the valve and repeat.  Sorry, I don't remember which way makes it hotter and which is colder.

Here is where I bought mine, I left the valve body in place and just replaced the guts.  The picture here should help you find it, it's facing away from you.  A flashlight and a mirror on a stick are not bad things to have. 
Valve, Tempering, 120øF to 160øF, AH

Good luck, and let us know what you find out, I'm very curious.

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Douglas and Amanda
1997 40' U320 "Brawley"
2007 Ford Explorer Eddie Bauer
Motorcade #17266 Escapee #113692

Re: Why is my cold water hot?

Reply #13 –
Quote from: ScubaGuy –

So the questions for you are:
How hot is the cold water?  Is it the same temp at all three taps?  If you open the tap full cold for 5 minutes does it get colder?
Seems the best way to get a fairly accurate temp is to fill a cup and then use an instant read type kitchen thermometer.  Trying to use an IR gun doesn't seem to give very accurate readings.

Good luck, and let us know what you find out, I'm very curious.

Yes, the heat exchanger is hot.

The cold water is HOT.  Even after letting it run for a couple of minutes in either the kitchen sink or bathroom, it is still almost too hot to hold your hand under.

However, a solution is at hand.  Brett has offered to come over from Livingston tomorrow and show me the ropes.  Like I said earlier, I love this forum and helpful attitudes I find here.

Glen
Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099

Re: Why is my cold water hot?

Reply #14 –
The hot water problem is resolved.  Brett (Amos.Harrison) pulled into my driveway Wednesday in his testosterone-laden Chevy SSR convertible and began helping me troubleshoot my electrical issues (on another thread) and my hot water problem.

The hot water was fairly easy.  I had already turned the thermostat in the bay all the way down trying to cool the bay but the exchanger was still very hot.  It turns out that there was one more click to turn it completely off.  Turning it completely off shut the heating off to the bay.  Brett quickly agreed that the bay thermostat was bad, and was calling for heat all the time.

Brett then turned his attention to my electrical problems, and that took a lot more time and trouble.  I'll discuss this in the thread I started about the electrical problems, but in the end it required a trip to MOT to repair what Brett diagnosed.

I took the coach to MOT the next day to get the electrical issues resolved.  I was amazed that they got me in so quick, and actually did the repairs while I waited.  While they worked to replace the power cord reel I discussed the bay thermostat issue with Keith Risch.  He too agreed that it was a faulty bay thermostat and quickly replaced it.  Problem solved.  I now have both hot and cold water, and the Aquahot isn't staying on all the time.

I really appreciate people like Brett taking the time and interest to help newbies like me.  Brett, if you read this, just know that you'll always be welcome here anytime you're in Livingston.  Bring your BMW over and we'll go for a ride if you're not picky about riding with a Goldwing.  :)

Glen
Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099
 

Re: Why is my cold water hot?

Reply #15 –
Glen, i was concerned that since we looked at coaches you had these problems it may have seemed not the best start, kinda soured things....but your good humor continued and as we balance life against other really more serious issues...as you know...i am comforted all is well with you.

The other Brett was generous and MOT lived up to the standards i have seen, often.  Looking back too, other members of the Forum speculated what i think was close to the final diagnosis?

All is good, friends matter...and maybe Other Brett can qualify for your Gold Wing BBQ?

Cheers Glen, stop by when in Nac

Mike
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches