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Old 12-03-2022, 09:49 AM   #1
Montana Master
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Suburban tankless

Hi guys been scouring the internet looking for info on how to descale my unit. So far nothing the manual says to use vinegar and that’s it ……. Lol

Anyone have some insight on how to descale the suburban tankless hot water heater ..?

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Old 12-03-2022, 01:19 PM   #2
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On the Suburban site, it says this:
Each year drain the water from the system and flush the heat exchanger with an approved descaling solution and use of our kit 521163. Contact your local RV service center for assistance.

Doing a search for Suburban approved descaling solution brought up several items, and this is one of them:

Not sure what that part number is for.
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Old 12-03-2022, 05:05 PM   #3
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Last2die - somewhere on the Airxcel suburban site you can find a pretty picture of my sketch. I need to descale mine also but I am going to have to go to Home Depot first and buy some plumbing stuff. Our units do not come with descale apparatus unfortunately.

I have never done this but I have thought about what I need to do and prefer to put it off to a future sunny day along with several other projects. When you find the suburban document - check my description and make sure I am not leading you astray or on a wild goose chase. This is my interpretation of the procedure.

To access the heater - remove all the crap you have collected in the basement. You will need to remove the rear bulkhead wall to get to the back of the heater. It’s a good time to clean and rearrange the basement - or at least the water heater side.

I think you need to turn off the heater in the hallway control center. Turn off the water supply to the camper.

1. Cut in some valves (V) on the cold supply and the hot water supply so you can cut off the descale solution (I am going to use a vinegar mix if I can’t find a bottle of fancy stuff) from going into the RV plumbing.
2. I plan to add some connections for garden hoses near the valves to connect the garden hose sections - maybe short hose pigtails for a feeder hose and a waste hose so you can feed the vinegar into the heater and a hose to direct waste vinegar to a catch bucket.
3. Get two 5 gal buckets. One to hold fresh vinegar solution (A) and one for catch bucket (B).
4. You will need to buy a small pump from Home Depot/Lowe’s to suck the vinegar from the bucket A and pump it thru the system. A pump like this will run $100 to $150 and you will use it every year.
5. Turn the isolation valves and start pumping the stuff thru the system…in and out. For my system - I might stop the pump and let the vinegar sit in the pipes for 15-30 minutes - then finish flushing the vinegar from bucket A. I do this to our Keurig coffee maker for descale - so I will do it on the heater also.
6. Fill bucket A with fresh water and flush it thru the system.
7. Pour the waste solution on a weed or fire ant bed somewhere and holler “Drink it up suckas and good riddance!”
8. Remove your garden hoses, turn the valves back to normal flow, put your hoses and pump in the bucket and stick it somewhere safe until next year.

I have seen a complete kit for this on Amazon a few months back but the reviews on the pump included in the package were very bad. I think we will get a better end product by cobbling the pieces and parts as I describe above. My description is rough and probably needs couple more valves or caps to plug the garden hose pigtails.

The suburban document references a kit (mentioned by Rohrmann) but I called every dealer suburban referenced in the Austin area and they had no idea what I was talking about. Don’t waste your time looking for the kit. Airxcel suburban will not sell it to you direct and the dealers are clueless.
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Old 12-03-2022, 09:45 PM   #4
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Oh wow well they sure didn’t make it easy or user friendly…. Thank you for the description it does make more sense.
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