Dimensions | Three-pipe Bleeder
8654 and 8655 Bleeders have aluminum bodies to minimize rust problems. They are furnished with four interchangeable orifice plugs. One is undrilled, the other three drilled for various bleeds indicated in Table A as "Standard." To determine most appropriate orifice, divide maximum gas pressure at ratio regulator outlet by air pressure; then use the orifice giving the next lower % impulse pressure. The bleeder and the filter are intended for use on low pressure combustion air only and have a maximum operating pressure of 2 psi. In the example on the front side: 10 osi gas 14 osi air = 71%. Use the 57% (#32 drill) orifice. Or bore it out with a #38 drill for 70% impulse. To determine optimum orifice through trial and error: Light burner, bring it to high fire, and adjust limiting orifice valve for desired air/gas ratio. Insert smallest orifice (#32 drill) into "M" opening in bleeder. If flame indicates drop in gas flow, use this orifice; or make a smaller one by drilling blank plug. (It is desirable to have impulse pressure as high as possible as finally set via the bleed at high fire; and the smaller the orifice, the higher the impulse pressure.
I f #32 orifice dœs not cause a drop in gas flow, try successively larger orifices until an effect is observed.
Readjust limiting orifice valve for desired air/gas ratio. Burner will maintain that ratio at all firing rates.
TABLE A
Impluse as a % of air pressure
Orifi ce
part
drill size
number
10
# 8
OA2-0401-1 OA2-0401-2 OA2-0401-3
30 57
25 32
15
15 19
20 40 70 82
29 38 44
User can make one of these orifices by drilling blank plug included with each bleeder or by enlarging one of the 3 Standard orifices. Drill plug from end opposite slot. Remove burrs and insert plug so slotted surface is about ½ " below surface.
DIMENSIONS inches
¼ NPT "A" air impulse in
¼ NPT "M" open or to Burner mounting plate or combustion chamber
2-5492-1 orifice cleaning brush and instruction plate
½
max. seating depth for Orifice Plug
8654 Bleeder wt. 1 lb
¼ NPT "R" out to Regulator
A
M
R
inner hole 1⁄8 NPT for Orifice Plug
two ¼ " pipe plugs (remove to clean orifices)
1 ½ 7⁄8
2
3 1⁄8
¼ NPT out to Regulator
½ NPT air impulse in
8655 Bleeder and Filter Assembly wt. 2 lb
¼ NPT "M"
2 3⁄8
¼ " pipe plugs
3 ¾
FLOW
7 ½
9 1⁄16
Bulletin 8654/8655 Page 3
To order, specify: 8654 Bleeder, or 8655 Bleeder-Filter.
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