One zone 'unresponsive'

[ISeeDeadBTUs]

I woke about 4 AM and since I was up, I checked the GW. It was at 180 (currently running aquastat at 192), but maybe the load had gotten hung up earlier. Anyway, I reloaded then so as to not have to reload in an hour or so. When I went inside I realized the main zone was at 63 with the 'stat set at 67. I let the oil burner come on and it ran about 1/2 hour, during which time all zones save two turned off. Unplugged the oil and went back to bed. (It was -3 °F at this point).

Got up about 6:30 (now -5 °F and the big zone (approx 832 [\])was still only at 64, so I plugged the oil back in. Less than 1 1/2 hours and the zone was back to 67. But that's when I found out that the master bd zone (approx 408 [\]) was at 61!! WTH?!?

I checked the circulators. The larger zone was set at 'High' (Grundfos variable speed) and the smaller zone was set on 'Med'. I moved the latter pump up to 'High' but it's been set at 'Med' since it was installed and I have never seen this happen before. I put my ear to the pump when I up-shifted and I could definitly hear it speed up.

It's almost like someone cracked a window back there!! >:-(

Not really a "boiler room" issue I know, but I'm open to ideas . . .

Jimbo

 

[sootsucka]

maybe circulator is air bound are they the same ones for the oil and wood

 

[Mike T]

Have you changed any settings before this happened?

It sounds like a pressure issue, but you are the man on the spot. Anything similar happen before?

Would I be right in assuming the zones without heat are in the smaller loop?

 

[djblech]

Do you have zone valves. I usually replace at least 1 zone valve moter per year.
Doug

 

[RowCropRenegade]

Do you have zone valves. I usually replace at least 1 zone valve moter per year.
Doug

what type of zone valves?

 

[ISeeDeadBTUs]

Though the old Grunfos sounded fine, I replaced it with a new one. Hard to test it now though, since it's 20 °F .

 

[ISeeDeadBTUs]

Ok, so . . .

I come back from getting some wood, and find that 5 out of six zones are on! The Viessmann had DHW priority, and is set at 140. The DHW was 131, which means it had been 'trying' to make DHW for some time, depriving the zones. I killed the slab zone, killed the DHW, and got down to three zones.

I finally gave up and called my heating/plumbing contractor. He got me down to the point of asking how much pressure was in the boiler and the gauge read ZERO!! There was a shut-off valve shut, not allowing water into the boiler. Obviously when I drained out about 8 gallons attempting to remove air after replacing the circulator, I ASSUMED this water was being replaced. Apparently not so :smirk:

Anyway, after a while the pressure came back, and DHW heating returned to normal. I checked the pressure about 1 hour later though and it was just shy of 30! I drained a bit of water/pressure, shut the shut-off again when I got it down to 20. This morning it was just shy of 10 so I opened the shut-off again (I am looking for 12-15 #)

While the hard-to-heat zone that triggered this post can now heat up, I'm not sure if it's only because the temps are now 20, basically 25 degrees warmer than the last couple of mornings.

I've read it said by someone here about how most people want to go to a thermostat and turn it up when they are cold and that's all they know about heat. That attitude is irritating as he!! when they stand around and watch you while they whine about being cold :shut:

 

[Chris S]

Be wary of pressure swings such as you are describing. One reason for such swings is an undersized or failed expansion tank. This would cause higher pressure with higher boiler temperatures. pressure drop as temperature drops. This should not happen.
The other concern, the reason a lot of us leave fill valves closed, is it lets you know if you have a leak. In a worse case scenario, a leak on an upper floor with an open fill valve can cause major water damage ( and your house is still cold) whereas if the valve were closed you'd have minor water damage and a cold house.
I've seen where leaks under slabs- undetected as make up water was continually added- rusted out a boiler in 2 years.
I'm for leave the valve closed. In your case Jimbo, it sounds like the issue started with you draing water to purge air so I'm not suggesting the worst, but I know you'll keep an eye on it ( you're here aren't you ! ) And sorry, still no pictures for you
Chris

 

[ISeeDeadBTUs]

Thanks Chris . . . I am going to continue to monitor the pressure. My contractor recommended leaving the water off fo just the reason you stated.

btw, thanks also for not posting pics of you running around the house in your shorts

 

[PJF1313]

. . .

I've read it said by someone here about how most people want to go to a thermostat and turn it up when they are cold and that's all they know about heat. That attitude is irritating as he!! when they stand around and watch you while they whine about being cold :shut:

and they are usually the ones that yell the loudest at the the bill... and why it took you so long to - get here; get parts; get it running after the last a-hat FUBAR it (and I DON'T wonder why...)