HW heater stopped heating with both 110 and LP

[1nolaguy]

Our Attwood 10 gal two way has been regularly cleaned and serviced and generally used on 110v when we are with hook ups. It has never had a issue. Last fall, due to an impending hard freeze I drained the WH while in storage. This spring, on our first trip, I refilled the tank through the system (city water) and turned on 110v. While the light on the switch came one the unit did not heat. I though perhaps the element got damaged while traveling dry. I switched to 12v and LP. Again the light in the switch came on but the system did not heat. The 110 CB is on and not thrown. Any help or suggestions would be greatly appreciated.

[Rick A]

Could it these little Thermostats. There are 2 of them. They set the max and min temp range. (Assembly Replace for Atwood 91447 Replacement Part for Water Heater Repair Parts Fit For RV, Motor Home Emergency Cutoff Service Kit https://a.co/d/4V3rB30  thermostats)

Suburban’s heaters are different. 

[Martinvz]

Something else to check is the fuse that is connected to the thermostats to ensure is is not burnt.

[Ted Carbonaro]

Can you hear the propane furnace fire up when you switch it on 12 volt? If not It could also be the control module. 

[1nolaguy]

Martin, is this an inline fuse or in the 12v panel near the 110v cb panel?

6 hours ago, Ted Carbonaro said:

Can you hear the propane furnace fire up when you switch it on 12 volt? If not It could also be the control module. 

Ted, I do not hear LP flow when 12v is switched on. It is as if the wh is "dead".

Thanks all for input. Before I order a new thermostat kit, is there a way to test with a MM to verify it is the thermostat or the control board? I would prefer not to just start replacing parts if possable.

[veraken]

Here's the Atwood Water Heater Service Manual which may help

 

Water Heater Service Manual - Atwood.pdf

[Martinvz]

Loel, the fuse is in line right behind the external access door. It is normally in a clear plastic tube.

[MyronTruex]

Did you reset the heater bypass valves to the proper position after winterizing?

[1nolaguy]

1 hour ago, myrontruex said:

Did you reset the heater bypass valves to the proper position after winterizing?

No, just emptied all tanks including WH. We live in the deep south. We only hD a few days below 30 all winter so no need for true winterizing.

Thx, will check that this morning.

[1nolaguy]

So, Just an an update: I ordered new 91447 replacement parts / Thermostat kit, which should arrive Wednesday. In the meantime I checked continuity across the existing thermostats (ECO and Temp Set) and it was good. I also checked the 2Amp fuse on the Circuit Board, and it was good. Currently we are experiencing a thunderstorm so after this passes. Since I already ordered the thermostats I will change them but I suspect this is not the issue as they have continuity. If either was bad and not able to pass current they would not have continuity. Unless there is another inline fuse I missed, continuity at the CB mounted fuse also rules that out.  Back to the service manual. Thanks again Veraken.

[MyronTruex]

 

I'm trying a simple copy and paste so bear with me.

This is a simple schematic for my ten gallon unit. If you have the same model it should be easy to diagnose with the diagram.

You could have two problems which is not uncommon. For example, you may not have 110 volt going to the water heater since it can pass through an load shedding relay. Access to the water heater back would be very helpful and a few pictures might elicit more help. 

If you have 110 to the water heater then it should be easy enough to see if that voltage is getting to the heating element when the switch is turned on.

Since you seem to have both sources of heating not working it could be the circuit board on the water heater but one step at a time.

You already know where the thermostat snap disc live so getting a voltage measurement on each side of those would be an easy place to get important information.

Notes and schematic.pdf

[1nolaguy]

Well this is a little delayed but the thermostats finally arrived. I went to install but before I pulled the originals I did a continuity test and both showed continuity as well as the 2A fuse on the circuit bd. The connections looked a bit oxidized so I cleaned them and coated with no-ox before reinstalling. I was planning to test the electric connection once more before replacing the ECO and Therm when I accidentally hit the nylon plug in the tank and it broke off soaking me with water. Sooooo

Now I have a different issue I would appreciate ya'lls help with.

1) Half the nylon plug threads are still in the tank. Is there a preferred way to remove this without damaging the aluminum threads in the tank?

2) The local hardware store did not have a replacement nylon plug but did have a brass one. I know brass and aluminum can have issues but am I OK using the brass with Teflon tape temporarily until I can get a nylon replacement?

3) If the thermostats show continuity are they good or it more of a resistance issue (ohms?) than continuity? Should I go ahead and replace them since I have new ones or just save the new ones for future need?

Any help is greatly appreciated.

[Tom Cherry]

40 minutes ago, 1nolaguy said:

Well this is a little delayed but the thermostats finally arrived. I went to install but before I pulled the originals I did a continuity test and both showed continuity as well as the 2A fuse on the circuit bd. The connections looked a bit oxidized so I cleaned them and coated with no-ox before reinstalling. I was planning to test the electric connection once more before replacing the ECO and Therm when I accidentally hit the nylon plug in the tank and it broke off soaking me with water. Sooooo

Now I have a different issue I would appreciate ya'lls help with.

1) Half the nylon plug threads are still in the tank. Is there a preferred way to remove this without damaging the aluminum threads in the tank?

2) The local hardware store did not have a replacement nylon plug but did have a brass one. I know brass and aluminum can have issues but am I OK using the brass with Teflon tape temporarily until I can get a nylon replacement?

3) If the thermostats show continuity are they good or it more of a resistance issue (ohms?) than continuity? Should I go ahead and replace them since I have new ones or just save the new ones for future need?

Any help is greatly appreciated.

Ironically, this happened to me over the weekend.  I did a quick fix and it worked.  I assume from your description that the nylon plug is s hollow, external threaded tube.  So, it sheared flush with the mating part.  Mine was a threaded fitting that screws into the body of an irrigation head.  What I did was this.

I used a razor or Sheetrock knife.  I carved or cut two notches in the inside body of the sheared fitting.  They are 180 deg apart.  They don’t need to be huge slots from a depth or length or width standpoint.  Sort of a slotted spanner wrench design…rather than the two pins.

 I mounted the head in my vise, horizontally.  I grabbed a pair of side or diagonal cutters.  The outside edges of the blade on my pair was forged with a flat spot or maybe a slight beveled “edge” on the outside.  I then used my hands and spread the cutters and pushed into or leaned into the head. I rotated, counterclockwise, the pliers until the outer edges sort of fell into the two slots…and then really pushed hard and rotated.  Took a few tries, but the nylon (pvc) fitting started to turn…..once i had 3 threads out, i used a long nose skinny pair of locking pliers and bingo….2 turns later….OUT.  Never cut into the major diameter of the internal threads of the head.

AS to the longterm fix.  The reason, I think, that a PVC plug was used was to prevent “BiMetalism”.  That is the galvanic (like a battery) action or chemical reaction of two dissimilar metals….COMMON OCCURRENCE.  Thus. Brass Plug will eventually corrode and become WELDED to the tank.  I would use pipe dope or anti-seize compound….but fix it with the PVC or CPVC or “nylon” plug…

I am a retired engineer…..but a few months ago, my GS’s TPMS caps were “welded” on.  I mistakenly ordered Aluminum (with O ring) valve stem cover caps.  August.  In November, no issues.  But in .April….CORRODED and welded.  I finally with finger pressure and a small adjustable wrench broke 2 loose.  I had to hold the UNPLATED Brass portion of the valve stem and then the wrench (hex head on cap) to break loose #3.  #4 actually sheared off the brass,,,,,and there was no valve stem in place.  ce….INSTANT DEFLATION or .flat tire…..He attends a college in the NC mountains and worked at a ski lodge that kept the highway and parking lot heavily salted.  bimetalism and galvanic with a coating of an electrolyte.  Instant corrosion snd welding…

Good Luck…

[1nolaguy]

Yep Tom, I am concerned about galvanic corrosion because I am in the coastal LA and the air is salty. PVC is not rated for hot water and CPVC was not available in the size I need. Will try to get the remaining plug out as you suggested; and yes it's Hollow.

[1nolaguy]

Well I had to pull the burner and cb to get at the broken plug. Looks Luke it is going to have to come out in phases.

While the cb was out it appears to be burnt in two connections. Is there a way to test before ordering a replacement?

[1nolaguy]

For those who may experience the issue of a broken Attwood WH plastic plug, after trying several approaches I fount the Orbit Riser Extractor (I bought mine locally at HD) https://www.amazon.com/Orbit-Sprinkler-Plastic-Extractor-26076/dp/B000I1RQZ8/ref=sr_1_3?crid=1LXE9RFLWZHJ4&keywords=orbit+nipple+extractor&qid=1687480225&sprefix=orbit+nipple+extractor%2Caps%2C286&sr=8-3. <ade quick work of removing the broken plug. The down side is I thought the plug was a standard 3/4" plug but neither a nylon or brass one will fit. Apparently it is an Atwood 91827 1/2" drain plug although it seems bigger than that. Tomorrow is another trip to the hardware store. Hopefully they will have one to fit.

Edited June 23, 2023 by 1nolaguy

[1nolaguy]

Well this is a follow up although I am not sure if it should be moved to LP section of the forum.  I replaced the thermostats and CB an now the HWH appears to have electricity. The LP side fired up but after about 30 sec the blue flame changes to a sooty yellow flame with reduced gas flow. I turned in on and off several times and each time it did the same thing: clicking sound followed by woosh and ignition followed by hi gas pressure and blue flame for about 3 seconds and then drop to low pressure and yellow sooty flame.

Based on your experience is this a solenoid issue (needs to be replaced) or something else?

Also, The new thermostats do not fit under the three metal tabs so are being held in place by the black foam pad. I plan to replace with another brand (any recommendations?) but is this safe to use temporarily?

 

[1nolaguy]

BTW- If you have to replace a plug you may have difficulty putting in the new one. Most plugs are straight and any buildup in the threads my prevent screwing in the new plug. My solution was to get a 1/2" pipe nipple and some oil. Oiling the nipples threads I put the nipple in and out using it like a die. After a couple of passes I remove the nipple, clean the aluminum threads of oil, use a little teflon tape and installed the plug. Easy peasy.

 

[Tom Cherry]

On 6/22/2023 at 8:38 PM, 1nolaguy said:

For those who may experience the issue of a broken Attwood WH plastic plug, after trying several approaches I fount the Orbit Riser Extractor (I bought mine locally at HD) https://www.amazon.com/Orbit-Sprinkler-Plastic-Extractor-26076/dp/B000I1RQZ8/ref=sr_1_3?crid=1LXE9RFLWZHJ4&keywords=orbit+nipple+extractor&qid=1687480225&sprefix=orbit+nipple+extractor%2Caps%2C286&sr=8-3. <ade quick work of removing the broken plug. The down side is I thought the plug was a standard 3/4" plug but neither a nylon or brass one will fit. Apparently it is an Atwood 91827 1/2" drain plug although it seems bigger than that. Tomorrow is another trip to the hardware store. Hopefully they will have one to fit.

I did not see this post.  Thanks for the link.  I probably lucked out on mine as I could fit it in my bench vise (horizontally) and make the spanner notches and then had s pair of diagonal cutters with a “square/sharp” edge and then spread and force them and caught the threads.  That is a cool tool. I worked for a hand tool company and we bought just about every competitor’s version of our product and they were thrown into a box and free, if someone tipped you off before they were discarded…..so I have lots of duplicates and also collected some really great tools when I traveled internationally.

Glad you got it out.

[1nolaguy]

I am not sure if ya'll quit following this discussion or if my post above got missed but since the issue still exists and I could use some help in figuring this out I am re-posting my question.

.... I replaced the thermostats and CB an now the HWH (Atwood) appears to have electricity. The LP side fired up but after about 3 or 4 sec the gas pressure drops and blue flame changes to a sooty yellow flame. I turned in on and off several times and each time it did the same thing: clicking sound followed by woosh and ignition followed by hi gas pressure and blue flame for about 3 seconds and then drop to low pressure and yellow sooty flame.

Based on your experience is this a HWH gas solenoid issue (do they need to be replaced) or something else? I do have electrical continuity across both solenoids

Also, The new thermostats do not fit under the three metal tabs so are being held in place by the black foam pad. I plan to replace with another brand (any recommendations?) but is this safe to use temporarily?