Category
Draft Pressure Transmitters for Furnaces & Boilers
Measure furnace, boiler and kiln draft with low-range transmitters from Halstrup-Walcher and Beck.
A draft pressure transmitter measures the slight negative pressure, usually just a few pascals, that keeps a furnace, boiler or kiln burning safely and efficiently. Halstrup-Walcher's P 26, P 29, PS17, PS27 and PU/PI/PIZ, and the Beck 985, cover ranges from 10 Pa upward in unidirectional and bidirectional versions, with ±0.2% FS accuracy on the P 26 and P 29.
6 Products · Draft Pressure Transmitter
Draft Pressure Transmitter 985
Draft Pressure Transmitter P 26
Draft Pressure Transmitter P29
Draft Pressure Transmitter PS17
Draft Pressure Transmitter PS27
Draft Pressure Transmitter PU/PI/PIZ
Selection guide
Draft Pressure Transmitters for Furnaces & Boilers Guide
How a draft pressure transmitter works
A furnace, boiler or kiln runs slightly below atmospheric pressure so that any leak draws air in rather than pushing flue gas out into the building. The transmitter measures that small negative pressure, often just tens of pascals, and its signal feeds the combustion control loop that adjusts the induced-draft fan or damper to hold the set point.
How to choose a draft pressure transmitter
- Direction: choose a bidirectional range, for example ±50 Pa, if the pressure can swing positive during start-up or upsets; choose a unidirectional range if it always stays negative.
- Accuracy: the Halstrup-Walcher P 26 and P 29 give ±0.2% FS with high overpressure protection; the PS27 is a compact, cost-effective option for basic applications.
- Approval: the P 29 is TÜV-certified for natural gas applications without Ex-zone requirements.
- Features: the PS 17 offers an optional relay and display for local alarming and readout.
- Selectable ranges: the Beck 985 offers up to 8 selectable pressure ranges with a 0 to 10 V or 4 to 20 mA output, useful when one unit has to cover several boiler sizes.
- Precision class: the PU/PI/PIZ series is available in several precision classes for tighter draft control.
For general low-pressure transmitters outside the draft range, see pressure transmitters.
FAQ
Common questions
What range do I need for boiler or furnace draft?
Most draft applications need a range of a few tens to a few hundred pascals. Tell us the normal and maximum draft your burner or induced-draft fan produces and we'll recommend a Halstrup-Walcher or Beck 985 range that keeps your set point well within span.
Why choose a bidirectional draft range instead of unidirectional?
If the pressure can swing positive, for example during start-up or a damper upset, a bidirectional range such as ±50 Pa shows both sides of zero. If draft always stays negative in normal operation, a unidirectional range gives more resolution across that one side.
Which draft pressure transmitter is certified for natural gas?
The Halstrup-Walcher P 29, which is TÜV-certified for natural gas applications without Ex-zone requirements, making it a common choice for gas-fired boiler draft control where that certification is specified.
What's the difference between the PS17 and PS27 draft transmitters?
The PS 17 covers plus and asymmetric pressure ranges and offers an optional relay and display. The PS27 is a compact, cost-effective transmitter aimed at basic draft applications where those extra features aren't needed.
Can one draft transmitter cover several boiler sizes?
The Beck 985 offers up to 8 selectable pressure ranges from a single unit, with a 0 to 10 V or 4 to 20 mA output, which suits a site or OEM with several boiler or furnace sizes stocking one spare model.
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