Descaling a tankless heater

[5wndwcpe]

As per my earlier post, I'm planning the radiant heating system for my new garage and have elected to go with a tankless heater. I plan on draining the unit in the summer as it will be a closed system. Does anyone know off hand what the proceedure is for descaling the heater ? I'd like to perform this as a seasonal service and build in the appropriate valves/drains beforehand.

 

[Steve in Mi]

Would you have scale if you use DI or distilled water?

 

[5wndwcpe]

Truthfully, I don't know as I have to descale it at all. It just seemed like a good preventative maintenance course of action, especially since I was planning on draining the system for the summer months anyway.

 

[Vicegrip]

Contact a hydronics treatment company or do some online reading. You can treat the water to prevent damage to the piping and scaling for little money or effort. Do not drain the system and let air into the system. Keep the treated fluid in the system and let the O2 in the fluid run down to near 0. Correct PH and inhibitors is all you need to keep the system fluid good for many years. Distilled or deionized is not required for standard systems unless your water is rock hard. Scale is more a problem of open systems. Treat it and test it every year or so.

 

[paul29]

You will probably using an glycol solution , what would be your reason for draining ? It should be good for many years . Most Manufactures have a tech line for questions such as this . Takagi 's tech line is 1-888-882-5244 , I'm sure Bosch or whatever brand you decide on has the same service .The Takagi I have , has freeze prevention by way of electric heaters on the piping inside the cabinet which turn on automatically and prevent the unit from freezing down as low as 5 deg F under certain conditions , of course this would not be necessary with an antifreeze solution . Once the minerals in a closed system react there is usually not much more scale build up until you add more water with more minerals .

 

[5wndwcpe]

I thought perhaps leaving the system empty throughout the summer months was better than having it sit and stagnate. Should I need to crack into the system, I didn't know what kind of bug-a-boos grew in the water over time.

 

[Steve in Mi]

The hot water heating system in my home has been opened up 3 times since 1978. Once for a new circulation pump, one time so I could install a new boiler (original TRIAC lasted 1961 to 1999) and the last time to add a loop for heating ~300 sq. ft. enclosed breezeway. I have my own well water with a little iron in it so I put either distilled or rain water in to refill. Hard to grow bug-a-boos without oxygen.

 

[BowtieNut]

Truthfully, I don't know as I have to descale it at all. It just seemed like a good preventative maintenance course of action, especially since I was planning on draining the system for the summer months anyway.

The controller I have on my system (Taco I think) will run the system for a few minutes every day even in the summer. Although I was told that this is more to keep the pump from freezing up during months of non-use than for stagnant water isssues.

 

[Tscott]

You Should not have to worry about scale in a closed system. I used to service restrant equipment here in Florida. This included commercial steamers with built in boilers. These units were open system and need descailing regularly (once a week or more ). Scale build up is caused when water boils off and leaves its heavier dissolved elements behind. This causes these minerals to concentrate and coat everything. In a closed system you will always have the same amount of water, and as long as the water moves everyone in a while, you should have little to no settling of minerals.

Also, I would be careful not to use distilled water unless instructed by the equipment manufacturer. I worked on an autoclave with an aluminum tank once. The customers water was filtered with a reverse osmosis system and the water was so clean that it became extremely reactive and ate through the aluminum pressure vessel. Draining the system seems unnecessary as well just follow the manufacturers instructions and it will serve you well for years.


Tom

 

[5wndwcpe]

Thanks for all of the replies fellas !

 

[comp]

Thanks for all of the replies fellas !

what did you find out ????? leave it closed ?

 

[5wndwcpe]

I think I'm going to go with a closed system and use a glycol solution for freeze protection. I like the idea of running the system for a few minutes every couple of weeks in the summer just to keep the system active. My concern was letting the system sit dormant all summer, which is why I planned on draining it in the first place. One of the above posts lists a controller that will cycle the heater automatically in the off season and I think that's the route I'll go.

 

[comp]

sounds better