Hydro-Hot

[Ken Sair]

Recently had a (2) problem with zone 1 heater on our Hydro-hot.
     Zone 1 heater would run for about 10-15 seconds and shutoff (the corresponding red light would light up on the control panel). I also noticed the overflow coolant tank was low. The HH tank itself was full. I topped off the overflow and took a break.

     A short month later I went to use it again and I found the coolant low in the overflow tank. I searched high and low for a leak or evidence of a leak and found nothing anywhere. So, I got out my trusty hammer (after topping off the coolant tank) and had a nice chat with the HH. Zone one started and I gently tapped all the pipes I could reach. The HH ran flawlessly and continues to do so to this days, 2 months later. I should mention we have plenty of hot water and zone 2 works.

      Now, 2 things have happened. The coolant tank is again about 1 inch below the 'cool' level. Still no signs of a leak anywhere. Second, There is a very light gray smoke coming from the exhaust (there was none when this started a few months back). I am unsure if these two items are related but I am no expert by any means. Any opinions on both or either of these two items would be greatly appreciated.

     Additionally, the unit is serviced regularly, used regularly and has 90 hours since its last service. Thanks, Ken

[Steve Huber]

Ken,
Light grey smoke is an indication of incomplete burning of fuel. Suspect either a new nozzle is needed or the alignment of the electrodes is off. In either case, you'll need to access the burner. I'd go for the  nozzle replacement if it's been a couple of years since last done. You can also adjust the electrode at that time. I doubt you changed the electrode alignment with your hammering.
As to coolant loose, check around your "radiator cap" on the HH. It can leak slightly and the antifreeze doesn't show on top of the unit, but runs down the back of the HH under the external box skin. Use your finger and check under the rubber gasket around the cap.
Also, check the area near your coolant pumps. The fittings that route antifreeze through the bulkhead above them can crack and leak slowly. There is a check valve there for each zone. Your hammering may have freed up a stuck valve. If leaking, you can replumb w/o the check valve and the unit will work just fine.
Finally, check the plastic line from the plastic expansion tank to the unit. It can get brittle and leak, but since the unit is warm/hot, the antifreeze "disappears". I replaced mine with rubber vacuum hose.
Good Luck. Steve

[Orman Claxton]

Hello Ken,
When checking your coolant  level, remove the rad. cap, go to auto supply, purchase a 13# cap, check the coolant at the Boiler (under the cap) fill to the top. install cap, check hose to the coolant tank.
Check the exhaust, is the smoke wet? if it is wet, make sure your extended warranty is paid up. otherwise an annual service will probable take care of your smoke
Call me if you need.
good luck

[Ken Sair]

The boiler tank is full and the radiator cap is new. That was the first thing checked.

I will check the line to the overflow tank today. Also the smoke to see if it is wet.

Its just strange. The smoke was clear when the front zone heater would stop working. After tapping the valves lightly and topping off the overflow tank the light gray smoke appeared. Those two things should not have changed that. Hmmmmm?

Anyway, thank for the help. I will check those asap. The HH is getting a workout this weekend, teenage granddaughters!!

Ken

[Steve Huber]

Ken,
If you tried starting it a number of times unsuccessfully, you probably have a build-up of fuel in the burner. Start it and let it run for 15-20 minutes and see if the grey smoke stops after it runs awhile.
Steve

[Ken Sair]

I ran it for an hour today. Teenage Granddaughters, man can they use up hot water!! The coolant overflow tank was low but not empty. I checked the overflow tank tube and I could not find any leaking. The light grey smoke was heavier on start up but diminished the longer it ran. After about 20 minutes the smoke was minimal except when it went from shade to sunlight. Don't know if that makes any difference.

Orman, I checked the exhaust smoke and it is dry. I guess that is some good news. Other than the light gray smoke it is operating just as advertised.
Ken

[Orman Claxton]

Ken
That gray smoke maybe coolant, does it have a pinkish color? check the feel immediately after start up.
I have a feeling, if you are using coolant and no sign of external leak, it could be internally,
pull the burner out, if it is an internal leak. there will be moisture inside the burner chamber
just saying.....
good luck

[Ken Sair]

Thanks Orman. The color is not pinkish and after I topped off the overflow tank it seems the same level even after usage.

I will pull the burner. I have a new nozzle I want to install anyway. I will check for fluid in the burner chamber.

Thanks again. Good luck on the coach repair!!

Ken