Author Topic: HydroHot top-off  (Read 6414 times)

George Harwell

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Re: HydroHot top-off
« Reply #15 on: October 12, 2020, 02:54:29 PM »
Joel, many times when the fluid drops below the float switch be prepared to see the float stuck . After replinishing the tank you may have to nudge the float lightly if the low fluid light remains on. Float will usually return to normal operation in most cases.
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Joel Ashley

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Re: HydroHot top-off
« Reply #16 on: October 13, 2020, 08:05:26 AM »
Yeah George, today during a rain break I went out and the cap came right off when I pressed down for the second detent.  The fluid was right up to the top of the filler neck, too.  So I took the panel off the unit’s front to see the layout relative to reference documents and articles I’ve accumulated over years.  If necessary I can drain the tank low enough to remove the level “sensor” switch and check or replace it.  Rains began again. 

When I can I’ll see if I can insert a clean rod or stiff wire of some sort through the filler neck and gently dislodge the switch‘s float.  Is that how you did yours, or did you remove the entire float switch?  I might also jumper #15 & #16 on the circuit board to verify the switch is indeed the problem.

One thing I’m not familiar with is the drain valve setup... it’s not like images I have of it.  It’s white PVC, not brass, conveniently extends out past some wiring looms, etc., and terminates with an opening that has a plastic sleeve inside it that’s loose and turns easy, but doesn’t seem to come out.  Deeper inside, before the plastic (ball?) valve itself, I see an “O” ring.  It’s like it’s meant to have a 1/2” I.D. hose pressed into it for draining purposes.  Am I on the right track with that interpretation?

I will need to consider that I don’t need this happening on a trip, and may replace the old float switch regardless whether I get the float working again.  I guess there is a newer electronic version that can report the fluid level... to an app or what I’m not sure.  It’s probably spendy.

Joel
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Eric Maclean

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Re: HydroHot top-off
« Reply #17 on: October 13, 2020, 03:14:12 PM »
Joel I believe the float switch is a magnetic contact switch when the fluid raises the float to a horizontal position there is a magnet on the back side of the float arm which when brought into proximity with the switch will cause the switch contacts to close making the circuit .
In your case as the fluid has not gone down below the float you would assume the float should not have dropped down / out and that the problem would there fore be the switch contacts .
How ever that assumes the float hasn't developed a crack and sunk.
Your on the right track play with the switch and see what you find you could Disconnect it and checking with an ohm meter while you play with the float to see if the switch part actually works

On a side note the older Aquahot like my 412 did not have a float switch and as a result when I got mine the burner pot in the tank had been run low on coolant and had developed a crack ( when the system was running the crack would open up and allow antifreeze into the burner chamber cause large clouds of white smoke like a bad head gasket in a car engine)
I ended up using a plasma cutter to remove the chamber from the tank and canalized another DBW 2020 webasto truck coolant heater to get the chamber I needed to weld back into the tank.
Interestingly when taken apart you can see where the Aquahot people had done exactly the same thing cutting the outter can off the DBW 2020 to use the burner chamber in there tank arrangement.

Anyway your on the right track
Good luck
Eric
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Fred Brooks

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Re: HydroHot top-off
« Reply #18 on: October 13, 2020, 03:17:26 PM »
    Joel,
 I would check the float switch at terminal 15 and 16 as this is the easiest way to stay on task and evaluate that. Most likely if the unit has set dormant for 4 years, the float switch is bad. You will have to drain the unit below the access port for the switch removal. I use an old fresh water pump to back fill the unit thru the drain to burp any anti-freeze up to the fill neck. Hope this helps, Fred
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George Harwell

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Re: HydroHot top-off
« Reply #19 on: October 14, 2020, 01:04:40 PM »
Joel, I used a long screwdriver to gently nudge the float. Since the tank was full when you removed the cap it appears that your float has become a sinker, not a float. I have changed my float numerous times and I have to siphon the fluid into a clean pail. My unit does not have a drain valve. As others have said do test the switch. Jumping can be a short term fix but removes your protection in case of a leak.
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Joel Ashley

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Re: HydroHot top-off
« Reply #20 on: October 14, 2020, 11:34:20 PM »
So, the solution refracted to 38% (protected to 0 degrees F).  I may add pure antifreeze to the expansion tank's Cold mark (~2-3 cups) just to compensate a bit more in the direction of 50% when it ever got drawn into the main tank upon cool down.

So Fred, have you seen a drain valve terminus like in my photo?  Will a hose just press in and pull out?  I don't have a spare pump, but do have a hand one.  It's been used for water and for oil transfers, though, and I'd rather not risk contaminating this job.  If I held the drain hose above the unit and funneled fluid in that way, would that do?  Or if I just put fluid in via the cap, wouldn't running/cycling the unit, as per some instructions I've seen, purge air from the lines?

Joel






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Fred Brooks

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Re: HydroHot top-off
« Reply #21 on: October 15, 2020, 01:39:50 AM »
  Hi Joel,
 I am pretty sure a piece of 1/2" Pex will push into that opening then a 1/4 turn on that valve. Give it a try. I have used that cheapo fluid transfer pump from Harbor Freight to top fill coolant tanks but not for back-filling against the existing head pressure of the contained coolant. As I recall, about 1 gallon will get you below the access port for the float. If that is all you remove, just just pour it back in after you change the float switch. Cycle all zones with the t-stat and do 2 complete cool downs and top it off. Fill the recovery tank with pure pink Boiler coolant and take that sweet heart for a ride. Fred
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Joel Ashley

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Re: HydroHot top-off
« Reply #22 on: October 15, 2020, 02:21:35 AM »
Okay, will do, Fred.  I just finished draining what I think is enough out.  A 5/8 OD hose fit just by pressing it in... no leaks.  The piece I had was only a foot long, but I sent it down under the rig by way of the burner fresh air duct that's flexible thin rubber and that easily moved to make room.

Yes, when I jumpered the circuit board connectors, the thing fired up.  I tried dislodging the float, but it's hard to feel around what's happening in there.  Afterwards, it still wouldn't work, so now I'm having an issue getting the float's wires tucked into a 7/8" deep socket enough to get the socket over the switch.  I'm going to go get a 7/8" deep socket for my half inch socket wrench, to see if the wires will fit.  I could cut them, but I'd still have to have a socket for the new switch's wires anyway.

Stay tuned.  The numbers on the switches tags don't match the suggested switches in my literature, so will have to check with AquaHot I guess.

Joel
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Fred Brooks

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Re: HydroHot top-off
« Reply #23 on: October 15, 2020, 03:02:19 AM »
   Joel, Just wrap the wires around a phillips screw driver and remove and tuck inside a deep socket and out she comes. Glad to here you are making headway. Fred
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Joel Ashley

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Re: HydroHot top-off
« Reply #24 on: October 15, 2020, 03:08:18 AM »
Well, the new deeper 7/8" socket takes more wire in, but I still can't get it over the switch.  Are we sure they didn't use a 15/16"-headed switch on some units?  Maybe that's the real problem. 

I hate to ruin a new socket, but if the switch is indeed 7/8” then maybe I’ll try using a metal blade to cut a notch in the side of the socket, kinda like the hole in a whistle, to route the wires through.  That would be less traumatic on the new switch’s wires too.

Now it's dark out, I promised Lee a 2 hour drive to visit her 92 year old brother tomorrow, and I don't have a replacement switch in hand yet.  That’s more important... she hasn’t seen him for a year, and we lost my own brother in May.   So I reckon this oft-interrupted job will be on hold until Friday or when I get a switch.

Joel
« Last Edit: October 15, 2020, 03:46:03 AM by Joel Ashley »
Joel and Lee Rae Ashley
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David Ciotti

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Re: HydroHot top-off
« Reply #25 on: October 17, 2020, 03:12:33 PM »
Speaking of radiator caps, when I tried to remove the cap off my 2002 Beaver Marquis it fell apart into many pieces.  Where can I get another cap>. AutoZone is no help.  This cap has two seals so it can suck fluid from the overflow tank.  The AquaHot is model number AHE-100-02S. Serisal number 01-1219.
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David T. Richelderfer

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Re: HydroHot top-off
« Reply #26 on: October 17, 2020, 06:39:28 PM »
The first link tells me the p/n plx-102-229 cap will fit your Aquahot (same unit I have, BTW).

https://heatmyrv.com/product/radiator-cap-13-psi-aqua-hot-rv-hydronic-heating-plx-102-229/


  The cap found above at $18 I thought was a bit too much, so I dug deeper. Then I found this link to a cheaper supplier on EBAY.  More searching may find a yet cheaper replacement cap.

https://www.ebay.com.sg/itm/Aqua-Hot-Hydro-Hot-13lb-Radiator-Cap-PLX-102-229-10229/174343697874?hash=item2897b1b5d2:g:4FgAAOSwrbVfB1EI


Hope this helps.  BTW, several years ago I purchased a new radiator cap at an Autozone or O'Reilly's.  It's been on the unit since then and it seems to work.  I don't remember the p/n of the cap I purchased.
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Joel Ashley

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Re: HydroHot top-off
« Reply #27 on: October 17, 2020, 09:19:15 PM »
I think that’s the same cap as on mine, PLX-102-229, David.  My recent looks online imply there’s basically two caps made for Aqua/HydroHots, and one has a “D” ring or “ bail” on top: PLX-403-000.  That one is pretty obvious, making it easy to tell which cap any of us has.

Joel

Addendum:
Now for our daily dufus handyman update.  Having struggled for hours trying to get a 7/8” socket over the float switch, even an Autozone trip for a 1/2” deep socket to better accommodate its two wires, today I almost cut a notch in the side of that socket to pull the wires clear.

But before that, I cleared away crushed insulation foam from around the switch base.  Nope, that wasn’t it.  Feeling in there with my fingers, I could swear the socket was too small.  But, no, the website and other documents I have all said the older units used 5/8” and mine should be 7/8”.  I tried Fred’s ‘wrap wires around screwdriver’ trick.  Nope after countless rewrap attempts, jamming the wires deep into the large 7/8” half-inch drive socket.

Frustrated by both that and the position this old body had to take for the job, I finally swore the da#*@! bolthead just had to be bigger than 7/8”.  So I dug out a 15/16” socket, but just strung the wires through it since I don’t have a deep one in that size, and wasn’t connecting the wrench.  Sure enough, even free of clogging wires, it wouldn’t go over the bolthead!  Okayyyy....

Out comes the 1” socket.  Bingo!  Slid right over the bolthead and is snug. 

Lesson:  when they say the switch is 7/8” they mean the threads, Dufus.  NOT the wrench size. 

So now, off to the Ace or Autozone for a half inch drive, 1” deep socket.  And hopefully wires will stuff in enough for the socket to slide over the bolthead.  The old one, no biggie, but I don’t want to risk damage to the wires on a new $150 switch.  If necessary, I can still cut a gap in the socket side.

-Dufus
« Last Edit: October 18, 2020, 12:23:47 AM by Joel Ashley »
Joel and Lee Rae Ashley
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George Harwell

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Re: HydroHot top-off
« Reply #28 on: October 18, 2020, 08:14:02 PM »
Joel, I guess I have changed my switch 8 or 10 times over the years and I figured it out long ago. I drilled a hole in the socket for the wires to pass through. Wasn’t easy, went through 3 or 4 drill bits but it was worth the effort.
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Richard Davis

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Re: HydroHot top-off
« Reply #29 on: October 18, 2020, 08:45:40 PM »
Joel
The best solution is to acquire a special purpose deep socket designed to remove and install oxygen sensors.  The socket has a slot cut into the side to allow for the wires to protrude while in use.
Richard
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