HTP INDIRECT WATER HEATER

Steve Whitbeck

How do you guys clean the scale build up off the heating coil.

Was told to drain the tank and then heat the heat exchanger hot but didn't have good results doing this before.

icesailor

Cleaning an indirect:

If the coil is encrusted on the outside, on the potable water side, it is because the hot water in the coil is causing the hardness in the potable water to boil out on the hot indirect coil. It is not easy to remove the coil.I've never heard of anyone trying to do it. And with success.

Being the adventuring sort, and forced to try to do something, I would drain the tank and put enough gallons of white vinegar to cover the coil completely. Run the circulator for some time, occasionally.  Let it set for as long as practical. Flush the crud out the drain. You will need to figure out a way to get water into the other side of the heater (hot). If you get chunks of white stuff, you are removing it. You will need a lot of turbulence to get it moving. White Vinegar by the gallons cheap and safe and you can buy it in the El Cheapo section of the Supermarket.

 

Steve Whitbeck

SSU 60

That would take at least 30 gallons of vinegar.

The heating coil is not removable on the HTP products.

icesailor

Cleaning Coils:

Steve, my heritage from a land in the northern British Isles would compel me to buy Vinegar in sufficient quantities to try this. If it works, and I have no reason from experience, that it won't, would compel me to try it. 30 gallons of vinegar is far cheaper than a new indirect.

MikeL_2

Try Rydlyme.....

Steve: I use a product called Rydlyme made by Apex Manufacturing. It is safe and effective, but will discolor most metal finishes. I use a 4 to 1 ratio  ( 4 parts water ) to pump through stubborn mineral laden domestic hot water coils. I save the fluid when done and reuse it to remove scale from toilet bowl rim / siphon jets..............

icesailor

HTP Indirects:

If the inside of the coil was the problem, you could do that. clean the inside. In these indirects the boiler water is pumped through the inside of the coil and makes the hardness residue form on the outside of the coil. To submerge the coil on the outside, you have to add enough cleaner to cover the coil inside the tank.

Steve Whitbeck

Calcisolve

I have used Calcisolve many years ago on the same model indirect at a different customers and it worked great - but that was before I learned about acid and stainless steel.  This heater is 18 years old and has a heavy build up. Customer is willing to replace the unit if the cleaning doesn't work.

MikeL_2

Rydlyme will work.............

Icesailor: I understand the difference between the two coils and was merely sharing my experience with a proven product. Apex tech support will help determine the most effective ratio needed to dissolve the scale from the domestic side of the indirect.................

spd

snake

I was just wondering what a snake could do for this. If this is an insidious problem maybe you are running the coil too hot. Would it be safe to snake it, anyone?

icesailor

Snakes in the water:

The coil is in the potable water and the crud is on the outside. The boiler water goes through the inside. The inside doesn't need to be snaked. It's clean. It's the outside.

spd

yeah

Maybe it would knock some of it off but it is pretty crusty. 

icesailor

Hungry Snakes:

The problem is being caused by "hard" water. Calcium hardness is coming out and forming on the outside of the coil. Like it would on a tankless coil in a boiler. Only it would be on the inside of the coil.

spd

hard water

If you don't want to do the experiment you should soak it in vinegar and treat the  water. I still think it might knock it off. 

SWEI

acid cleaning

I buy sulfamic acid in 50# bags from a chemical supply.  Works quite well, not so hard on your copper and brass.

Steve Whitbeck

SWEI

It's not the copper that I am worried about it is the stainless steel tank.

Acids and bleach can eat holes in the tank.

SWEI

Stainless alloys

Sulfamic acid is easier on most metals than acetic or citric, and any of these are less aggressive than HCl (on people as well as metals.)



Probably worth doing a bit of research on the alloy in question. http://www.nibco.com/assets/ChemGuide.pdf has some info, but is hardly complete.



Several companies offer corrosion-inhibited sulfamic formulas that present even less risk to metals.





.

icesailor

clean HX'ers:

Most tankless water heaters (the on demand type) need to be serviced and cleaned. Zoller sells a system that has a small PE tank and pump inside with hoses and hose connections. You are supposed to use Vinegar in it. White Vinegar is absolutely safe. You can make salad dressing out of it and clean your dirty coils.

Hey, I don't know if it will work. I, personally would at least try. Its try or a new tank. I only suggested that because the coil is quite low in a SuperStor tank. I'd call HTP and ask them about it. That's what they are for and how much fluid will you need to cover the coil.

kcopp

I talked a...

number of years ago w/ a HTP rep. They recommended this. indirect power(tt off)Drain the tank. Then Run the zone w/ the aquastat on high. let this run for 5 min. Pull out the aquastat well. Then w/ a "wand" 3/8 copper w/ a hose adapter on one end and small 1/8" holes in it insert the wand so it goes into the middle of the coil and run very cold water on to the hot coil. ... this should shock the junk off the coil... repeat this several times.