Author Topic: DIY Hydro-Hot Element Replacement (Long)  (Read 5447 times)

Bill Sprague

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DIY Hydro-Hot Element Replacement (Long)
« on: February 12, 2010, 05:41:45 PM »
My Hydro-Hot electric element burned out after 6 years of heavy use in a 2004 Beaver Monterey.   The first clue was cold water for a shower and the second sign was a zero amp reading on the Aladdin monitor.  

Tools required:

screwdrivers
jumper wire
1 1/2 socket
24 inch breaker bar
24 inch extension
modified old socket
hose and fittings (5/8s ?)
gallon jugs
voltmeter

The Hydro-Hot shop manual has trouble shooting steps of confirming 12 volts on two wires at the circuit board, the same 12 volts at a relay, continuity on the high limit thermostat, 120 volts at the element and lack of continuity on the element itself.

The next step is to get a new element, which I bought via mail from Roger Burke.  Good price, good service, fast response and some advice when I asked for it!  http://www.rvhydronicheaterrepair.com/

You can’t remove the element without first draining the coolant.  Most units have a drain valve near the burner unit.  Mine does not!  Beaver must have saved at least $10 by leaving it out.  The next suggestion was to remove a drain plug on the bottom of the unit found under the coach near the exhaust outlet.  It has a square hole in it that mates to a 3/8 drive extension. That was a good idea until I broke the 1/2 inch to 3/8 inch adapter on the end of a 24 inch breaker bar.  I think after 6 years of being in the same hole, that plug is now fused to the tank.  

Looking for an alternative, I called Hydro-Hot.  I left a message and was called back in 20 minutes!  It was suggested that I could disconnect the hose coming out of a circulation pump where it goes into the check valve near the top of the unit.  You can run the pump by “grounding” it.  There are two leads coming from the pump and apparently the positive lead is always “hot”.  The other lead, labeled as “6”, is the ground and, when jumpered to the frame, it runs.  All that is necessary is to remove the hose from the check valve, insert a hose fitting and attach a hose long enough to reach five one gallon bottles or a five gallon bucket.  (I think it was a 5/8 inch hose fitting.)  With the hose hooked up (and my friend Marty on the end of it aiming at the gallon jugs) I grounded the pump.  It quickly pumped most of the coolant from the Hydro-Hot.  So far, the only spill was about a tablespoon out of the check valve that I caught in a rag.

I suspected that there might be a little coolant left.  The element is low in the tank.  In case more would leak out as I unscrewed the element, I set up my overworked 1 gallon Shop Vac.

To get the old element out you have to remove a cover plate, move some wires out of the way and disconnect two wire terminals on the element.  Now you need a thin wall 1 1/2 inch socket!  Sears had big fat ones for about $50 to fit a 3/4 inch drive.  A better choice was a “element removal tool“ I found in the water heater department at Lowes.  It’s a socket that looks like a big version of the spark plug tool that used to come free with outboard motors.  It is thin wall tubing formed into a socket with two holes on the end.  On a real stick house water heater you are supposed to insert a screw driver into the holes as a lever handle.  On the Hydro-Hot I had to improvise to accommodate the tight working space.  I put a bolt in the socket’s holes and ground slots into an old socket which allowed me to attach an extension and breaker bar.  (The socket slots took about 5 minutes with a “peanut” angle grinder and vice grips.)

The old element was a little stubborn, but with a 24 inch breaker bar it yielded.  Once free, my friend Marty continued with a ratchet while I held the Shop Vac hose in close.  It sucked up about a pint of coolant that would have saturated the insulation around the element hole.  Once loose, the old element pulls straight out.  It had a hole in it and some corrosion.  

The new element screwed in with only a little difficulty.  Smaller hands worked better than bigger hands!  The new element was market with two “Up” locations and has a rubber gasket.  In one position it seemed too loose and we couldn’t get the other “Up” all the way to the top.  So, I am concerned that it may not be perfect, but I think it is close enough.  Although I’m sure there are some, we didn’t have access to any torque specifications.  We got as tight as we could comfortably with a 3/8 drive ratchet.

The coolant was a little dark and six years old.  Right or wrong, Beaver was using ethylene glycol when my rig was built.  So, to improve on corrosion control I replaced the coolant with new Prestone.

Last was the final test.  I turned on the element, the amp gauge showed 12.8 and the water warmed up!  No leaks, so I put everything back together.