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Technical Instructions
Document No. 155-516P25
Rev. 2, December, 1998

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Siemens Building Technologies, Inc.

Landis Division

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All pressure connection pipes must be at least ¼-inch inside diameter. For air to gas
pressure ratios over three, the air and combustion pressure connection pipes must be at
least 3/8” inside diameter. The pressure pick up conections must be flush with the inner
wall of the pipe or housing in order to sense turbulence free pressures. The gas pressure
pick up should be located at least five pipe diameters downstream of the valve. D

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e.... The pressure connection pipes should be as short as possible to

allow the regulator to react to sudden changes. The connection pipe for the combustion
chamber pressure must be installed so that condensing flue gases cannot enter into the
regulator but run back into the combustion chamber. If necessary, a water separator
must be installed.

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If minimum gas pressure detection is required, the
pressure switch must be mounted upstream of the
regulating gas valve to ensure sufficient gas pressure
before starting the burner. If maximum gas pressure
detection is required the pressure switch must be
mounted downstream of the valve.

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Air proving safety devices normally required to
guarantee minimum air flow must also be provided
when using the SKP70…

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In installations with negative air pressure the SKP70…
does not work unless a higher negative chamber
pressure is connected to the regulator.

 

Adjustment and indication of the gas to air ratio

Adjustment and indication of the bias

Connection for the combustion chamber pressure sensing line

 

Connection for the gas pressure sensing line

 

Connection for the air pressure sensing line

Stroke indication

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Summary of Contents for SKP Series

Page 1: ...he combustion air pressure without the need for an additional constant gas pressure regulator Since three functions safety shutoff constant pressure regulation and air gas ratio control can be performed by a single valve fewer components and fittings are required to assemble a gas train reducing both the size and the weight of the gas train significantly The total pressure drop across the gas trai...

Page 2: ... fitting See Figure 4 AGA78 A motorized pressure reducing control SQN37 can also be installed in the air impulse line to continuously optimize combustion when used in conjunction with an oxygen trim system P P P Pr r r ro o o odu du du duc c c ct t t t N N N Nu u u um m m mb b b be e e er r r rs s s s T T T Ta a a ab b b bl l l le e e e 1 1 1 1 P P P Pr r r ro o o od d d du u u uc c c ct t t t N N...

Page 3: ...imensions See Figure 6 Specification for valves See gas valve Technical Instruction No 155 512P25 Connections Conduit connection inch NPSM adapter Gas air combustion chamber pressure connections NPT Operating characteristics Output force 100 lb 450 N Maximum stroke 0 7 18 mm Opening time for maximum stroke 12 s Closing time 0 8 s Control signal Reference input signal Combustion air pressure Contro...

Page 4: ... pressure acts on the regulator causing the air diaphragm to move to the left and close the regulating hydraulic bypass valve When the actuator is powered the gas valve begins to open The downstream differential gas pressure immediately begins to increase until the downstream gas pressure is in balance with the air pressure in accordance with the pressure ratio adjusted on the regulator The bypass...

Page 5: ... SKP70 leakage due to diaphragm rupture stops when the burner shuts off and the valve is closed Conventional regulators continue to leak and therefore have to be vented to the outdoors N N N No o o ot t t te e e e To avoid oscillation do not oversize the VG valve See Technical Instruction No 155 512P25 F F F Fi i i ig g g gu u u ur r r re e e e 1 1 1 1 S S S SK K K KP P P P7 7 7 70 0 0 0 U U U U O...

Page 6: ...c c ce e e e The pressure connection pipes should be as short as possible to allow the regulator to react to sudden changes The connection pipe for the combustion chamber pressure must be installed so that condensing flue gases cannot enter into the regulator but run back into the combustion chamber If necessary a water separator must be installed W W W WA A A AR R R RN N N NI I I IN N N NG G G G ...

Page 7: ...oximately 90 of full capacity 3 Measure CO2 or O2 content in the flue gases and correct the ratio by adjusting screw until optimum values are obtained fine setting 4 Return to low fire and measure the CO2 or O2 content in the flue gases If necessary correct the setting by adjusting screw until optimum values are obtained 5 Limit the damper position for low fire operation If considerable parallel d...

Page 8: ... Fi Fi Fitt tt tt tti i i in n n ng g g g A A A AG G G GA A A A78 78 78 78 F F F Fi i i ig g g gu u u ur r r re e e e 4 4 4 4 A A A AG G G GA A A A7 7 7 78 8 8 8 O O O Op p p pe e e er r r ra a a at t t ti i i io o o on n n n F F F Fi i i ig g g gu u u ur r r re e e e 5 5 5 5 A A A AG G G GA A A A7 7 7 78 8 8 8 A A A Ad d d dj j j ju u u us s s st t t tm m m me e e en n n nt t t ts s s s Function ...

Page 9: ... d di ii ing ng ng ng T T T Te e e ec c c chn hn hn hno o o ol ll log og og ogi ii ie e e es s s s I I I In n n nc c c c Landis Division 1000 Deerfield Parkway Buffalo Grove IL 60089 4513 USA Document No 155 516P25 Printed in the U S A P P P Pa a a age ge ge ge 9 9 9 9 o o o of f f f 9 9 9 9 D D D Di i i im m m me e e en n n ns s s si i i io o o on n n ns s s s F F F Fi i i ig g g gu u u ur r r re...

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