soap thru machines?

A friend told me I should occasionally run a little dish soap thru my hot water machine. I guess it keeps rust from forming, although it seems to me it might cause scale buildup in the coil. Good idea? Is there a 'conditioning' product that would be better?

Tnx, Richard

I have been repairing machines for over 15 years and that one is a new one on me. You would be better off to run some light oil thru or coil clean of some sort.

Hello Richard,

When we put a new boiler in our truck we started to have brown/black water when the unit would set. It got so bad that the water (city water) was turning a dark color in the coil during a lunch break of about 1 hour!

The folks that made our boiler said "Well everybody runs soap thru the coil during the washing process and do not have a problem".

We never have and did not intend to inject detergent thru the coil. The way we solved the dark water problem was when we stored the unit we injected soap (Hot) and kept in the coil until the next time we used the system. Took many times but now we do not need to put anything in our water and no discoloration!

Seems like this would reduce the heat transfer and it may have but it was what we were advised to do!

Dave Olson

I think it was less the soap and just time that eventually caused a lime buildup in the coil.

Steel coils will have 'black water' on startup after sitting for a very short time. Simply this is rust and a natural byproduct of the water contacting the coil material. Over time, hard water deposits will form a lime scale on the surface of the pipe minimizing the amount and severity of 'black water'.

In high mineral areas (20+ grains of hardness) this can happen quite quickly, areas usually served by water well. In areas with soft water this may never happen, areas served by river water. We have been known to run a coil in our facility to lime it up for a customer to prevent what you describe.

You must be careful with injecting soaps into a hot coil. Many soaps have a high solids composition that will precipitate out in the coil. This will plug the coil and since soap is essentially alkaline will neutralize any attempts to acid clean the coil. There is no easy way to clean a coil plugged with soap, that is why we have gone away from high pressure soap application in the units we build (still offered as an option).

Some manufacturers gave extended coil warranties if you only used their soap. It is quite possible that it contained a coil conditioner to accomplish this.

Hope this helps? Cheers.

Hello Michael,

I was not a happy camper when I was told by two different manufacturers that I must add something (detergent or TSP) to combat the black water! This 1st thng they told us to do was put a baking soda slury thru the coil! One even suggested to add a lime mixture! I also contacted a local shop that works on boilers for buildings. They told me the same thing. Wait until the calicum covers the interior of the coil or put soap in it. But it you wait you will be degrading the coil!

When you clean "White" vehicles it is very hard to just wait for the rinse water to be clear!

The coil on our boiler is 3/4" Sch 80 pipe about 300 feet long. This a Lp unit rated at 980,000 Btu.

Dave Olson

The water we use is from a 300' deep hard rock well that is about 25 grains of hardness so we run a coil as hot as we can and it limes up in a couple of business days.

This does not eliminate the problem but does really reduce it. Unfortunately 'white' vehicles will require you to run the water for a couple of minutes before it clears enough to use.

A stainless steel coil, on the surface, would solve the problem. However, the high temperature variances cause the metal to become brittle and fail prematurely. Besides costing a fortune.

Hope this helps? Cheers.

try running vinegar in it it works on coffee pots and steam irons without dammage to humans or clothing.

Try disconnecting the coils at both ends and using a Sureflo pump to pull a rust & lime rerover through till you see it coming through the clear tubing just before the Sureflo ( do not run through Sureflo). Let chemicals set for at least 30 min. and then push fresh water through the coils and you will see all kinds of crud come out. I do this at least once per year. This will help keep the coils clean. You will find that it burns a little warmer. Coils are like arterties, they will have build up. This will also create less back pressure when you are using a down flow chemical injector.