Danfoss 074G0028 DST P070 Pressure Transmitter 0-32 bar

DST P070: a ratiometric flare-port transmitter for A/C and heat-pump OEMs

The 074G0028 is a Danfoss DST P070 with a 0 to 32 bar sealed-gauge range. The data sheet calls the series a pressure transmitter for demanding air-conditioning and heat-pump applications, drawing on more than 30 years of MEMS pressure-sensing experience, with a hermetically sealed media interface and a compact body.

Compatibility is stated for R290, R32 and other HFC and HFO refrigerants, which is why this device is found in modern split systems, chillers and heat pumps. The 32 bar range covers the high-side pressure of those refrigerants with margin.

Technical specifications

Ratiometric output and flare port

The three-pin Metri-Pack plug gives supply, common and signal, with the output proportional to the supply, so the controller should share its own reference. The 7/16-20 flare port is the standard refrigeration service thread; the store lists it as female and the sheet notes that some versions use a deflator pin.

The sensor withstands 96 bar overload, which is three times the range, and can see a medium up to 135 C. The total error band of 2 % in the compensated range, with a response time of 2 ms, is adequate for superheat and head-pressure loops.

Ordering and engineering notes

This is an OEM component, and the connector, harness and fitting must be matched to your design. The Danfoss data sheet separates the codes by range, pressure port and colour code, so compare the 32 bar, flare variant against the table before ordering rather than the closest range.

Seven Star LLC is an independent supplier in Muscat; send 074G0028 and the quantity to request a quotation.

Heat-pump and A/C builders frequently pair a high-side and a low-side transmitter on the same circuit, so ask us for both ranges in one enquiry if you need them. The solder-tube and flare versions of the DST P070 differ in assembly, therefore record the exact code on the build sheet. A wrong port type is the most frequent reason for rejected deliveries on OEM lines. We can also quote a few units for prototype work before a series order is placed.

A good enquiry for 074G0028 lists the code, the quantity, the site, the required documents and any approval certificates your inspector will ask for. Sending these together, rather than one by one, shortens the exchange and reduces the chance of a mismatch at delivery.

Our quotation for 074G0028 will state what is included, such as the document set and the packing, and what is not, for instance accessories or commissioning. Read these lines against your specification, and ask us to adjust the scope if your project requires something extra.

Applications in air-conditioning and heat-pump systems

The DST P070 in this range is used where an A/C or heat-pump controller needs a continuous pressure signal from the refrigerant circuit. Typical measuring points are the discharge or liquid line on the high side, where the signal is used for condenser control and high-pressure monitoring, and suction-side points whose pressure feeds the superheat calculation. Rooftop units, split systems, packaged chillers and heat pumps built by OEMs all use transmitters of this type, and the stated compatibility with R290, R32 and other HFC and HFO refrigerants matches the refrigerants used in current equipment designs.

Selection and integration

Select the pressure range to cover the highest pressure the circuit will see at the measuring point, with enough margin that normal operation stays inside the range. Confirm that the controller analogue input is designed for a ratiometric signal and that the transmitter supply is taken from the same reference as the controller measurement; otherwise supply variations appear as pressure errors. Match the flare thread and the Metri-Pack plug to the existing system design, and check whether the service port on the circuit needs a version with a deflator pin. Recording the full code on the build sheet avoids confusion between similar versions that differ only by range or port.

Installation practice

Install the transmitter on a port where the refrigerant pressure is representative and where liquid slugging or strong pulsation is limited. Tighten the flare connection following normal refrigeration practice without overstressing the housing, and support the wiring so that the plug is not carrying the weight or vibration of the harness. Route the signal wiring away from compressor and other motor power wiring, and leak-test the joint after charging. During commissioning, compare the transmitter reading with a calibrated gauge at a stable operating point.

Once the system is running, trend the pressure signal in the controller for a period and compare it with the expected behaviour of the circuit at different loads. A signal that jumps, drifts or sits at a fixed value usually points to a wiring, supply or reference problem rather than a fault in the refrigerant circuit, and checking these first saves time on site.

Operating conditions in Oman and the GCC

Air-conditioning equipment in the Gulf runs for long hours at high condensing pressures during the summer months, so the high-side measuring point is often working close to the upper part of its range. The ambient and medium temperature ratings in the table should be checked for units installed on hot rooftops in direct sun. The IP67 enclosure suits outdoor condensing units, but dust and salt air near the coast make it worth keeping the electrical plug clean and checking it during routine maintenance.

Documents and quotation

The attached document is the Danfoss DST P070 data sheet AI542132204553, which holds the ordering tables. See also pressure instrumentation.