Hydro Hot Problems

[Slabman]

I thought I had the HH working well, but now am having issues with it
putting out hot water AND heat. When using ELECTRIC only, I get about
20 seconds of warm/hot water when turning on a sink faucet, then it
decreases to cold. The floor heaters sometimes come on, but
sporadically. But when firing up the diesel burner, I can get the
normal unlimited supply of hot water.

Ambient temps are in the 30's today here in Dallas, but this problem
happened a couple days ago with 60 degree temps, so that shouldn't be
the problem. It seems the electric side IS working, but not enough or
on a consistent basis so as to thoroughly heat the water. The green
light on the switch is lit as is the electric diagnostic light on the
board, so it seems these are not issues either. I wonder if I have a
(low) limit switch problem?

I called tech help at HH, but the guy didn't seem to want to help
troubleshoot this with me....he wanted me to read about it on their
website.....(Nice help). Funny, but here I am ready to order parts
from them and no one wants to help.

Any thoughts?

[Al_M]

The folks that answer their tech support calls seem to be less
interested / qualified to answer questions than in the past. I called
a few days ago with a question about an oily discharge in the exhaust
and I did not get any help. I chaged the nozzle and the fuel filter
and so far it seems OK.l

I found the trouble shooting guide that is contained in their shop
manual (available on their web site) to be an excellent step by step
problem determination tool. There are several model dependent manuals
so check your model number first.

For my model the AC trouble shooting starts in section 7.10. I had an
electric problem with mine a while back. It was caused by the high
temp cutoff safety (Located in the electric element service box) in
the electric element circuit that gave me trouble. It's directly in
the 120VAC circuit to the element. Mine actually burned up. IMHO
it's far to small / fragile to be reliable long term. If I remember
correctly there is a single AC/DC control thermostat. Use care when
trouble shooting. Some of the proceedures require that it have AC
power applied.

Al

[Bishop at Supreme RV Service]

Bob,
The most probable cause for this issue is buildup on the electric
element. The electric element is not nearly as potent as the diesel
burner, 1500 watts of heating power vs 50,000 btu's. The time to
achieve maximum heat output is vastly different also, 20 minutes for
the diesel burner vs 2 hours with the electric element. I guess where
I am going to with all this data is that I agree there is a problem
with the eletric element but don't over think it. With such a small
heat source some build up over time can drastically reduce the
capabilities of your element.
Bishop

On Dec 10, 7:36 pm, Slabman <slabm...@gmail.com> wrote:

[Tow...@aol.com]

Bishop,

I am wondering if people should consider installing the Rinnai 180,000 BTU water heater.  My prototypes proved over 400% increase in efficiency and the system doesn't have any of the problems that I read and have heard about over the years. 

--My guess is that one problem may be the size of a propane tank that was provided in the original application.

--If this is a viable solution and betterment, I would be thrilled to come out to your facility to convey to "the guys" all of the do's and don't's that cost me tens of thousands in R&D.

--I have 2 residential MSWord electrical and plumbing schematics that I engineered for Rinnai's dealers that is free for the asking.  The concept is similar but on a smaller scale for the RV.  This is NOT a "do it yourself" type of application but is virtually flawless.

---One Rinnai dealer had 2 failures out of over 500 installations in a 3 year period.  I have been running these for several years with ZERO attention.

Rich

 

Richard Townsend
TOWNSEND BLDG & FINANCE
GREEN ACRES Camp Ground
"LIFE STYLE NATURE RESORT"
Year-round Full Hookups
800 664-1679 Fax: 603 664-6043
43 Hall Road - Barrington, NH 03825

 

In a message dated 12/11/2008 9:29:42 A.M. Eastern Standard Time, bis...@supremervservice.com writes:

>

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[Slabman]

Thanks, Bishop. Is there a way to either clean this element or
replace it? But I do think I have another issue here. This AM I
found the diesel burner worked great for 30 minutes and then the
burner shut down. After looking at the panel, I see the low fluid
level light was on, so it thinks I have low fluid. But there's plenty
in the overflow tank, so now I'm thinking I have a bad sensor. Can I
just jumper across the leads and trick it into working 'till I can get
a replacement? This would also help me diagnose the problem.

On Dec 11, 8:29 am, Bishop at Supreme RV Service

[Al_M]

The low fluid sensor is a float switch in the main reservoir. I had a
problem with mine. It seems that during travel it is possible for it
to get stuck and cause a false low fluid reading. I checked that the
main reservoir was full and bypassed the switch with a jumper since I
had scheduled a service call to replace the plastic drain that had
failed and was going to see the Vehicle Systems service tech in a
couple of weeks. The Vehicle Systems tech who serviced my unit at a
FMCA rally told me that it happens occasionally and that draining and
refilling the tank normally corrects the problem if the switch is not
defective. He drained mine since he had to replace the drain pipe and
valve with brass parts. The switch was fine when the tank was
refilled. He left me a spare switch that I have not had to replace in
two years. The switch is a bit strange in that it is designed to be
installed in either of two positions depending on the application.
Since it is possible that the line between the overflow tank and the
main reservoir may be blocked or that there is a problem with the
pressure cap, I recommend that you verify that the main tank is full
by removing the radiator cap when the tank is cool. Then you could
jumper the float switch to you trouble shoot your other problem.
Removal of the switch requires a "special" water heater deep socket.

Al

[Slabman]

Thanks for the info, Al. I did pop the cap and found fluid pouring
out of the opening since there is a direct line feeding fluid from the
overflow canister.....DUH? I tried to pinch it off so I could check
inside, but didn't have anything to clam it with and it was about -40
degrees out there. So I put a paper clip jumper in place and now it
works great!

I was going to order a new float switch, but now wonder about a wrench
to remove it. Are you saying a conventional deep socket won't work?
Where do I get one that does?

[Al_M]

The tool looks like this one:
http://ace.imageg.net/graphics/product_images/pACE3-4027327dt.jpg

There are a couple different sizes. I suggest that when you get the
switch, take it to and Ace Hardware or other similar store and get the
one that fits. They may carry them at Lowes or Home Depot. I've not
checked there. Bishop or someone else may recall the size. If I
remember to do it I'll take my spare switch out of the parts box and
measure it. An other option is to call Hydro Hot and ask them.

Al

[Slabman]

Hey, that looks like an ordinary spark plug too wrench that's included
in the kit that comes with your new $50K car purchase. I have one of
those...prob. didn't add but a buck to the purchase price, dontcha
think? I did order a new float switch from HH and the guy told me an
ordinary 7/8 in. deep socket would work, so I'm assuming that's the
case. There goes my trip to the "Sears adult toy store".......

[Slabman]

I finally replaced the old plastic float switch with the new one,
which is primarily brass. For those who will have to do this some
time, I can tell you the old plastic switch has a one inch head, so
you need a deep socket for it-just cut off the lead wires to allow
insertion of the socket. The new one, however, is 7/8 in. and you'll
need a slotted socket for it, since those wires can't be cut. I found
one at Auto Zone...commonly known as a socket for removal of a smog
valve. Yes, the new brass switch appears more robust for the task.

[trau...@aol.com]

whats the float switch for ?   thought they high temp limit switches where is this one located I would like to change it as a precaution

cause it will go down when I am in the woods

jon

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[Slabman]

Jon,
The float switch tells the unit you're low on fluid and will light the
light on the board and shut 'er down 'till you add more coolant. Be
sure to keep some coolant on hand.

If you take off the HH cover you will see the fl. switch as the
forward-most "plug" in the unit-about 2 in. below the top of the
unit. It has a pair of wires leading out to a bundle and if you trace
'em, they'll hook up to the control board above. There are actually
two similar-looking "plugs"...the float switch is the one to the
left. You have to drain about 1.5 gal of coolant from the unit to
remove it, or you'll have a gusher coming out of the hole as you
unscrew it. The new one from HH is a bout $85, I believe. You'll
need a hand pump to put the coolant back in the overflow tank once
you're done. Available at HD or WalMart for a couple bucks. And the
socket as described above. Pay attention to the orientation of the
old one and install the new one the same way. It needs to close the
circuit when fluid levels are high enough.

Now, if you're brave, you could just wait 'till it malfunctions on you
and install a jumper across the two fl. switch terminals on the
board. They are the upper two right side terminals. A paper clip
bent into a horseshoe makes a good jumper. Assuming you have no
leakage in your system, you could run this way for an indefinite
period, but be sure to watch your fluid level.

[Jon]

Thanks
I will look and probably do it on a warm day here in Miami
The last time I worked on it it was 21 and the wind was blowing 25 mph
the plastic drain started leaking
Replaced it all with brass and a ball type valve. That is one of
systems weak point is that drain

Thanks for the detailed info Slabman
Ps Slabman is that name associated with cement

Thax Jon

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