Hydronic Heater Coolant Leak

[severns@sprynet.com]

Hello, folks.

I am hoping to get some new ideas to solve a problem that I have been chasing for several months. We recently replaced the pumps that circulate coolant through our hydronic heating system. The heater and system work very well. However, since replacing the pumps, I have smelled coolant when the system heats up or when the engine heats up (all part of the same system). I know I am loosing some coolant. However, based on the measured loss, the leak is very small. I have cheeked every logical place for the leak and simply cannot find one. I even hired a professional who could not find the leak. I have checked al the obvious connections, hoses that I can see and taken apart some of the storage areas. What is worse, there are no puddles in the coach, under the coach or tell-tail leak trails.

By the way, we have a 1997 Country Coach Affinity. I would welcome any thoughts that you might have or ideas on how to track the leak down.

Thanks

Shawn

[aztec7fan]

Sean, Your leak sounds like a frustrating problem to troubleshoot. Since you already hired one professional, you might be willing to hire another to use a thermal imaging camera to possibly locate the leak. These cameras can show you minute temperature variations and might show you somewhere the coolant is spraying out with a fine mist or pinhole leak. Asfar as finding a company that does this, try the phone book (or internet or other sources) possibly for restoration companies that do water/fire damage restoration (thats what my company does, and how I know about these cameras).

Good luck,

Chris Guenther

Westminster, CO

F3508-S

[garykd]

Hi Shawn,

These are a couple of cheap and easy things you can do. Is your expansion tank metal or plastic? If metal, check the expansion tank very carefully once the engine it up to operating temp. What you are looking for is a very small pin hole or seal crack. There may be a trail of coolant, or not. Also, replace the cooling system filler cap (formerly called radiator cap). Over time they can leak small amounts of coolant and leave no trace.

[wolfe10]

Shawn,

Let's clarify-- you are loosing Hydronic heater coolant, not engine coolant, Correct?

How many ounces over what period of time are you having to add?

Is there a pressure cap on the hydronic heater reservoir. If so, have the system pressure tested (pumped up to more than standard PSI and look for leak(s).

And are you smelling the coolant inside the coach, in a basement-- where?

Is there a difference in smell of engine coolant vs hydronic heater coolant? Does that help locate the leak?

Brett

[severns@sprynet.com]

Wow! lots of good advice.

To clarify. The heater coolant and engine coolant is all one system. I have a metal pressure tank (checked for leaks) already but have never tried pressurizing the tank. The smell is mostly in the coach. It is strong in two locations, at the steering wheel (front of coach) and in the bathroom (back of the coach). It is a rear engine bus-like coach. Interestingly, there is almost no smell in the basement.

Thanks for all of your thoughts and suggestions.

Shawn

[wolfe10]

Shawn,

And how much coolant are you loosing per time period/mile?

So, in your system, when you are driving, engine coolant circulates throughout the whole hydronic system (including to all the in-coach heat exchangers, not just to the hydronic heater unit where a separate pump pumps a different coolant to the in-coach exchangers)?

Brett

[severns@sprynet.com]

Hello Folks:

Well it took pressurizing the system to find the leaks. There wasn't just one but about 10 different leaks that were difficult to find and only obvious as the various leaks were repaired. It wasn't cheap but it did get the job done.

Thanks for all your suggestions and help.

Shawn