The Steamboating Forum

The blow down procedure taught to me was slightly different;

1. Shut top and bottom Cockshutt

2. Open drain and clear the glass completely (leave drain open)

3. Open bottom cock (this fills the glass again) and blow through drain. Shut top cock (glass empties again).

4. Open top cock- any rubbish that could have been blown up the glass from filling from the bottom will now be washed out.

5. Shut drain with glass empty.

6. Open top cock (glass still empty)

7. Open bottom cock and watch the water level rise in the glass.

This procedure entirely isolates both cocks and proves they are working.

Greg

yes, both ways work, isolating each valve independently, also watching the glass before and after is a good idea, sometimes you can actually see a change in the water level after blowdown.

I think I have it. Now once you get the prophylactic in place is it safe even if your partner has moved on to re-arranging the furniture in the living room?

steamdon-jr wrote: 1. close the bottom valve
2. open drain for a few seconds this will force all pressure thru the top valve and possibly clear debris.
3. close drain
4. open bottom valve
5. close top valve
6. open drain for as few seconds, this will force all pressure thru bottom valve and possibly clear debris
7. close drain.
8. open top valve.

gondolier88 wrote:The blow down procedure taught to me was slightly different;
1. Shut top and bottom Cock
2. Open drain and clear the glass completely (leave drain open)
3. Open bottom cock (this fills the glass again) and blow through drain. Shut top cock (glass empties again).
4. Open top cock- any rubbish that could have been blown up the glass from filling from the bottom will now be washed out.
5. Shut drain with glass empty.
6. Open top cock (glass still empty)
7. Open bottom cock and watch the water level rise in the glass.

Both procedures work in my mind.

Typically I would close one cock, open and close the drain, change which cock was open, and open and close the drain again, but I would also from time to time have both cocks shut and the drain open to check for them leaking.
I also quite often just dib the drain with both cocks open to get the level to clear and re-settle, which also brings some colour into the glass if using a clear glass without a red line or stripped rear card.
We do not have open 'test cocks' on our boiler, but we do have two gauge glasses which operate independently, hence have redundancy.

The key thing I would add thats not been covered it that you can hear the difference between steam exiting, and water exiting and flashing off into steam, hence you during the above test procedures you can also check the level is between the top and bottom.

I was also told that you can blow a gauge down two often, and that its a significant cause of the wasting at the end of the gauge glass, so once a day seems more than enough, and I tend to try and do it before the boiler comes up to full pressure (200psi) say at 50-60psi instead, which is also the pressure our boiler tester recommends we blow down the boiler at.

Daniel