Power went out; CB 5036 water level raised 1/2"

[i'mstihlaguy]

I can't figure this one out. Power went out in the early a.m. a few nights ago for about 2 hours. When I got up in the morning, the pump had started up, the house was at the correct temperature and everything seemed normal. When I went out to check on the boiler I noticed some water had overflowed from the vent/fill pipe. Looked like not more than 2 gallons because it is on a slab and everything froze quickly (no water ran off the slab). The water must have came out slowly because it actually froze in icesickles ending in little mounds of ice right at the base of the OWB.

I though maybe this was water that backflowed from the house when the pump stopped because my lines run from the basement up two floors above grade. I have purged all air from the lines and the water level reads about 1/2" higher on the sight tube. It was right at the full mark before this happend. I know this is not a serious amount of water because it doesn't take much to change the reading near the top due to the shape of the water jacket.

I don't believe this is the result of a boil over because my set point is 175 and the water temp. never exceeds that temperature once the damper shuts. Any thoughts?

 

[mtfallsmikey]

Do you have check valves on your lines?

As long as everything's working ok/lines been bled don't worry...

Welcome to the CB Brotherhood of Boilovers!....wait 'till your damper solenoid sticks open!

 

[Scootermsp]

No circ pump running = boilover

 

[mtfallsmikey]

It's nice to have a generator for those special times too!

 

[i'mstihlaguy]

No check valves that is why I think the water might have backflowed. Why would the water level raise from a boil over? It should go down due to less water in the system.

 

[mtfallsmikey]

No check valves that is why I think the water might have backflowed. Why would the water level raise from a boil over? It should go down due to less water in the system.

It shouldn't raise....me thinks you may not have it bled out properly, the water will always seek a common level, the check valve(s) that CB recommends installing in the line are there to prevent that....I have issues with that if my primary circ's shut down, boiler water level is around 16" or so below the level of the HX in the house, but....I'm no scientist either, just stayed at a Holiday Inn Express last night!

 

[November Wolf]

Sounds like a boil over. Same thing happened to me when the power went out.

 

[builder1101]

got kids? get a crankin' wank 'em and let them have at it...

no seriously, i bought a 12vdc pump that's isolated at the moment, throw some valves, drop off a few batteries and with my solarpanel, i'm ready to rip.

 

[i'mstihlaguy]

It shouldn't raise....me thinks you may not have it bled out properly, the water will always seek a common level, the check valve(s) that CB recommends installing in the line are there to prevent that....I have issues with that if my primary circ's shut down, boiler water level is around 16" or so below the level of the HX in the house, but....I'm no scientist either, just stayed at a Holiday Inn Express last night!

You may be on to something but now that I think about it, I probably did not get all the air out when I filled it in November. I bled the lines properly after the power outage so even with the loss of a couple of gallons it could still read a little higher.

I guess I didn't take into consideration that I have about a 3 degree differential due to the side arm and loss in the heat exchanger (in the plenum) even when the blower is not running. So when the water stops circulating that must be enough to cause a boil over since no heat is taken from the system. Mystery solved.

 

[rx7145]

When the power went out the water temp went up over the set point. When water is heated it expands. And it just overflowed. I have had the same thing happen to me. Fill the boiler with cold water, then heat it up to 175* and it will overflow, even if it never went over 212*.

 

[i'mstihlaguy]

You are absolutely correct. I overflowed the boiler I had before this one for that reason. For the initial fill on the 5036, I kept the water level about an inch below the full mark on the sight tube. I started a small fire and brought it up to operation temp. very slowly keeping an eye on the water level. Once I got up to operating temperature, I topped it off very slowly to the full mark.