Atwood water heater preventative maintenance

[TheCatsRV]

Have a 6 gallon Atwood in a new-to-me '07 Coachmen Mirada.



The pressure relieve valve is frozen. It isn't hidden away.



https://1drv.ms/u/s!AnrZHGaAwtashJVa...G78uA?e=Tt5RkW


Can I take this and replace per this thread? https://www.irv2.com/forums/f54/atwo...ml#post5456687?



Unit is a 150 psi 3/4" thread Watts unit. Can I just use an equivalent Watts plumbing fixture to replace (saves me having to order/buy at a RV parts store and costs less to boot).


Also, should I put in an anode plug in place of the plastic even though strictly not required?


Also, does this burner need replacement or not yet?


https://1drv.ms/u/s!AnrZHGaAwtashJVb...jONXA?e=ojOw1G

[Old-Biscuit]

T&P Relief Valve is a Standard water heater relief valve

3/4" NPT threads and 4" probe
*Most any hardware store


Yes that burner tube has seen better days
*Rusting due to T&P dripping on it
Atwood 91638


As for an andoe rod......NO
Aftermarket sells them ---Atwood doesn't even have a part number for one
Nylon plug is used for reason:
*Drain plug threads are aluminum....nylon will not strip/damage the threads-----very possible with a steel threaded anode rod that is needed
*Drain plug is temp/pressure rated for water heater use....use nylon vs PVC/CPVC plugs

[TheCatsRV]

Thanks. That is definitely the Atwood part number? Photo is of the heater label.



https://1drv.ms/u/s!AnrZHGaAwtashJVc...9BBJA?e=30BqUq




What is T&P in this context?


I have the original plastic plug. So not even a rod that is one piece (thread same material as the sacrificial bit).

[Old-Biscuit]

Atwood 6 gallon all use the same burner tube

T&P......Temp/Pressure Relief Valve

Buy 2 pack of New Nylon Plugs
One to use/one as spare
Atwood 91857

[TheCatsRV]

Valve came out easy once I took out the exhaust vent shield. Lots of calcium build up which probably killed the PRV. Unfortunately the new PRV is a long type and the short ones are in short supply. Need to tap the tank thread to clear the gunk too.

[Old-Biscuit]

Originally Posted by TheCatsRV

Valve came out easy once I took out the exhaust vent shield. Lots of calcium build up which probably killed the PRV. Unfortunately the new PRV is a long type and the short ones are in short supply. Need to tap the tank thread to clear the gunk too.

How long is the probe?
Remember the tank is aluminum so Caution when 'tapping' those threads

[TheCatsRV]

Originally Posted by Old-Biscuit

How long is the probe?

It's the PRV that sits higher. A long shank



https://www.watts.com/products/plumb...valves/sl100xl



The OEM unit is a short shank that is in short supply



https://www.watts.com/products/plumb...ief-valves/10l

Remember the tank is aluminum so Caution when 'tapping' those threads

Was only going to tap a few turns to clean out the gunk. Anything else I can use to clean it out?

[Old-Biscuit]

Originally Posted by TheCatsRV

It's the PRV that sits higher. A long shank



https://www.watts.com/products/plumb...valves/sl100xl



The OEM unit is a short shank that is in short supply



https://www.watts.com/products/plumb...ief-valves/10l






Was only going to tap a few turns to clean out the gunk. Anything else I can use to clean it out?

That long bodied one.....access panel may hit it and not close

Threads are NPT (national pipe thread....tapered)
I use a brass 3/4" nipple and run it in/out a little at a time

Any hardware stores close by?
Check them for short bodied T&P and brass nipple

[TheCatsRV]

Originally Posted by Old-Biscuit

That long bodied one.....access panel may hit it and not close

It looks like it might just clear if threaded all the way in.

Threads are NPT (national pipe thread....tapered)
I use a brass 3/4" nipple and run it in/out a little at a time

I will try that. Or can I use the old valve? The gunk is stuck in the threads good.

Any hardware stores close by?
Check them for short bodied T&P and brass nipple

The local plumbing wholesaler which is a big regional chain (have an account for whatever reason) doesn't have them!

[tap4154]

I replaced my PRV about four months ago and Home Depot had boxes full of the short bodied ones. Ace had them as well.

[Old-Biscuit]

Gonna be close ....check old thread length vs New T&P
*number of threads screwed in

Wire brush the threads on old one and use it to clear the tank threads
*small wire brush stuck into the Tank opening can clear up the threads also


I understand the issue with availability.....area of Canada you are in
Have same problem with Home Depot in nearest town to us.

[TheCatsRV]

Had a better look at the tank opening today (not raining). The threads are quite galled and corroded where the original PTRV was not screwed in (i.e., less than half way). A tap may have cleaned it out but tap in the size are costly and largely unavailable. I tried fitting the tall valve and screwed it in as much as I could w/o excessive torque, after cleaning out with a brass brush as much as I could (didn't help too much). There's enough clearance at the top. Would be more than enough if I could screw it in a few more turns.

[Old-Biscuit]

Originally Posted by TheCatsRV

Had a better look at the tank opening today (not raining). The threads are quite galled and corroded where the original PTRV was not screwed in (i.e., less than half way). A tap may have cleaned it out but tap in the size are costly and largely unavailable. I tried fitting the tall valve and screwed it in as much as I could w/o excessive torque, after cleaning out with a brass brush as much as I could (didn't help too much). There's enough clearance at the top. Would be more than enough if I could screw it in a few more turns.

You could try screwing it in/out working it back & forth
But once it is tight DO NOT over tighten or you could strip the Tank bung threads or even crack the tank or bung weld
*can be rewelded etc but that would require removal of WH

**If tank bung threads are galled/pitted use couple wraps of Teflon Tape on T&P threads.
Tapered threads don't needed tape but when galled/pitted tape is good to use.