OWB gaining water

ButchC · March 19, 2018, 09:10:58 AM

Last week I noticed the slab was damp under the OWB so I kinda kept a closer watch on it and it was gaining water and overflowing. I by passed the domestic water heaters hoping it would continue because a leaking fill valve would be an easy fix but no luck it quit overflowing

So,, Water is going from the domestic side to the boiler loop at the heat exchangers. I have both a side arm and plate type. Side arm was a year ago with this installation, the plate is 10 years old from the original installation of the OWB.

Question is one or the other more likely to be the issue? The tube seems pretty simple?? Dont know a thing about what the plate looks like inside. I think I have figured out a way to pressurize them after removal. Just looking for ideas, Thanks!!

DDW_OR · March 19, 2018, 01:25:17 PM

here is my central boiled 750 install
NEW Central Boiler Install in Firewood and Wood Heating

sounds like your plumbing got crossed, or there is something wrong with your heat exchanger.

hedgerow · March 19, 2018, 04:33:57 PM

Those plate heat exchangers are pretty tough. If you don't freeze them or over pressure them they usually only plug up. Where I worked before I retired we took tube and shell out and put plate in because they lasted better. Why do you have both? I just run a plate with a pump on my domestic never run out of hot water.I run a softer so in 10 years I have never had to clean the plate yet.

E Yoder · March 19, 2018, 08:14:06 PM

I have seen acid water eat out the copper brazing in a plate exchanger and overflow the stove. Or a sidearm could pinhole too.

ButchC · March 21, 2018, 07:49:40 AM

Thanks all,
There isnt a crossed plumbing issue, it worked fine for 5 months before it started.

Why both? Long story.
We had a plate type for many years. Only (slight) issue was when there was no hot water use for long periods the tank would cool down. Then we moved and took the OWB with us. The dealer said a side arm would be the cure all for the tank cooling down so I bought one and installed it. Then we had a new issue the side arm couldn't keep up with my clean freak Wife's hot water demands. At that point I couldn't take it back so I put the plate exchanger back in line. They actually work great in tandem. The plate heats the water as you use it and the side arm keeps the tank hot overnight. Yes it's over kill.

DDW_OR · March 21, 2018, 11:11:48 AM

so, the side arm is new and the plate is old.

when the weather permits, you should take each one off and do a pressure test to see if either one leaks.