Electrical Smell from AO Smith GDHE-50 Powered Vent

[Spyder]

Found this site with a search. I bought a house with the AO Smith GDHE-50 gas water heater. When first looking at the heater it seems like a pretty advanced unit. We have had no trouble till a week ago. I noticed some water on the floor. The water heater is 8 years old and out of the 6 year warranty. I started investigating and found that the leak was coming from the high pressure relief valve and the T&P port. Then I went to drain and flush the heater but it was completely clogged with calcium deposits. At this point I replaced the drain valve with a 3/4" ball valve and probably removed 1/2 a bucket full of calcium deposits. I re-doped the ports and that seemed to stop the leaks. Then I replaced the drain tube that connects to the condensing exhaust drain on the bottom and noticed it has some rust flakes and was completely blocked but somehow the heater did not throw a code. Upon taking off the exhaust vent I removed a bunch of rust flakes. Then I noticed some water on top of the anode so I had to remove the blower to access the anode. It was completely shot and I replaced that. I even took out the burner and cleaned that up. One thing I noticed is that 3 of the 4 bolts that connect the burner plate to the top of the water heater had been stripped off and the last service guy just left the bolts on top. I tried everything to get those sheared off bolts out but I kinda just gave up. Now I am not a plumber more like a figure it out kinda homeowner handyman. I don't know if it is ok to just have one bolt and maybe figure out of way to secure that plate down, I was thinking of some sort of high temp glue? I know it would be tough to service again but I am just trying to get a little more life out of this thing.
I put everything back together and all in all I have hot water right now but I did notice when the small blower fan, see picture, kicks on now I am getting a electrical type smell. Not gas. I took the cover off the powered blower and checked the circuit board and it appears to be ok. Do you think I am smelling the burner chamber heat that is escaping from the burner because there is only 1 out of 4 bolts holding the plate where the vent connects to the top of the unit or am I smelling an electrical issue with the powered vent? In this unit the powered intake pushes the air down to be combusted and the exhaust is blown out of separate PVC pipe outside. I can't figure it out. Thanks

 

[Reach4]

If you have what you perceive as a possible crack letting combustion gasses out, furnace cement is cheap. It's like caulk that hardens, and it is made for high temperatures.

For the future, you might consider a softener. That will prevent deposits from occurring in your new WH, and it will make the water you use better for your use.

 

[Sponsor]

 

[Spyder]

If you have what you perceive as a possible crack letting combustion gasses out, furnace cement is cheap. It's like caulk that hardens, and it is made for high temperatures.

For the future, you might consider a softener. That will prevent deposits from occurring in your new WH, and it will make the water you use better for your use.

Ok I'll get some of that and put it around the plate. Yes I had a softener put in when we moved in. The one that came with the house was not working.

 

[Spyder]

Also I have the water heater set to 120 degrees and the differential defaults to 8 degrees. What should the differential be set to? I assume that is the point when the water heater starts up or shuts off? Plus or minus 8 degrees?

 

[Tim Ross]

The GDHE is a beast and loves to sit around 160deg, in my unprofessional opinion, I believe setting a higher tank temp keeps it from short cycling and helps it operate most efficiently, and will improve your dump capacity at point of use. Of course take whatever locally mandated precautions are necessary to keep everyone safe from scalding, but I wouldn’t personally run these tanks less than 150deg. Anything less is just wasted potential IMHO.

 

[Fitter30]

If you don't see any burnt or melted wires and smell the venter motor could be very hot.

 

[Reach4]

but I wouldn’t personally run these tanks less than 150deg. Anything less is just wasted potential IMHO.

That only makes sense if you run out of hot at 140F. At 150, the standby losses will be higher, but if you need hotter water to mix to give you the amount of shower water you need, then 150 makes sense.