Hydro Hot fluid goes where?

[dshogman]

Not using the heater, just the hot water for the past few months. A month ago the fluid was between cold and hot. Today it was at the bottom of the expansion tank. So where does it go??
Thanks.

[dshogman]

Not using the heater, just the hot water for the past few months. A month ago the fluid was between cold and hot. Today it was at the bottom of the expansion tank. So where does it go??
Thanks.

[jerry davis]

The tank on the side of the hydro hot is an expansion tank just like the one on your car's radiator. When the unit is hot the fluid expands into the tank, when cold it goes back into the heating chamber.

[Old Rv'er]

Hello All,
And there is an overflow pipe from the expansion tank, that allows extra (way extra) fluid to go out onto the ground. If you have that much swing on the level, I'm not sure if this is normal, but I would look for a leak just to be safe.

[Cruzer]

If you've had any service work done on it recently it can take quite a while for the air to burp out of the system, lowering the level in the surge tank accordingly. If the system hasn't been opened for a while and the level previously was good, then there shouldn't be any reduction in the level because it is a sealed system.

Ideally the level should be sest just above the cold line in the tank after the boiler has been allowed to cool down. Then, once the antifreeze heats up, it should never go above the hot level line.

If the level is going down, and all of the air has been purged from the system, then you have a leak. The most common places for this is the heat exchangers and the tank drain petcock. The tank drain is inside the burner access panel. It's a plastic drain valve that has a tendanacy to crack and leak. Your heat exchangers are located throughout the coach. They, as well as the various lines running to them, have compresion clamps that hold the rubber hoses onto the Pex lines. These can loosen up, creating a dribble and leak. Those are thefirst two places I'd check.

Remember, it's a sealed system. If all of the air is totally purged the level can't go down unless there is a leak someplace.

[dshogman]

Mark,
Thanks for the summary - pretty much the way I saw it except for the burp which I didn't realize. The system was serviced for a new float valve about 2+ weeks ago. When I got it back the fluid was about halfway up the tank. I only run it in the morning for a shower, so it must gave taken that long to burp So, will keep an eye on the tank now that I have it at the right level. BTW, plastic drain was replacd with brass about a year ago.
Next look will be the exchangers if need be - no signs of leakage under the coach or smell of fluid anywhere.
Thanks again.