Single pipe 5lbs near end of cycle

Fizz

with parallel system. Temp last nite and this AM -3 to 0, boiler ran longer with resultant low pressure gauge not working, change to 0-30lb gauge with resultant pressure of 5-6lbs last few minutes of run which lasted 50 min, normally 35-40'. Usually the 30oz gauge read 0, then would spike to 10-15oz last few min. Notice 2 rads making swoshing or grating sound after boiler cycled-out. Any thoughts?

Jamie Hall

What's the pressuretrol set at?

Fizz

,5 and 1lb. Several times this winter when pressure got to 18oz and 25oz system shut down. Honestly don't know if p-trol was reason or t-stat satisfied? the pressure remained low til last 2-3 min, then climb.

EBEBRATT-Ed

Sounds like your pressure control is set too high.

The pressure probably stays low or no pressure on the gage (which is what you want) and when the vents all close the pressure rises a bit.

You pressure may stay low normally but with cold temps and a longer run time your getting up to the pressure control setting

Chris_L

And when was the last time you cleaned the pigtail the Pressuretrol is attached to? Sounds like it may be clogged.

Fred

Either:
- Pigtail is clogged
- Pressuretrol needs to be re-calibrated
- Pressuretrol is not wired in series with the other safeties
- Pressuretrol has completed failed and needs to be replaced

Fizz

Pigtail replaced Oct 2017, and both the p-trol and gauge are on same pigtail. P-trol cut-in is 0.5, cut-out 1.0. Most recent run it pressure gauge was at 2.0 when boiler shut-down. Will try to clean p-trol, and if no go, then per Fred's list.
Thanks!