Agilent Varian VHS-400 Water Cooled Vacuum Diffusion Pump, ISO400K Inlet Flange, 17.72 inch OD, Maximum Pumping Speed 8000 l/s Air Standard Cold Cap, (2) 208 VAC 2200 Watt Heaters, Agilent Varian Part Number L9767307. The Agilent Varian VHS-400 has been designed to fill a special need in applications where high pumping speeds are required and space limitations demand a compact pump. The VHS-400 pump is a rugged, general-purpose unit with an operating range of 1.4 x 10-3 to <5 x 10-9 Torr at 4400W. The Agilent Varian VHS-400 is ideal for applications requiring fast cycling because of its high pumping speed (maximum rated at 8000 l/s with standard cold cap) air combined with high forepressure tolerance (0.65 Torr with no-load and 0.55 Torr when at full gas load). Backstreaming rate of the unit is 1x10-3 mg/cm2/ min, without the use of any cooled cold cap. This Agilent Varian VHS-400 Diffusion Pump Includes: ISO 400K (17.72 in. OD) No bolt holes ISO 63K (3.75 in. OD) No bolt holes Standard Cold Cap Recommended Roughing Backing Pump: 30 CFM 8000 l/s Maximum Pumping Speed Air 208 VAC 3 ph (4400W) with (2) 2200 Watt Heaters Water Connections 1/8 in. FPT Tee Designed To Be Used With Santovac 5 or IVP 704 Diffusion Pump Oil, 1000cc (1.056 Qt.) full charge Diffusion pumps use a high-speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the outlet. The oil diffusion pump is operated with an oil that has low vapor pressure. Its purpose is to achieve higher vacuum (lower pressure) than possible by use of positive displacement pumps alone. The Agilent Varian VHS-400 can pump down to pressures of <5x10-9 Torr. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump, roughing pump is typically used to maintain an outlet pressure around 1 mTorr. These Agilent Varian Diffusion Pumps are very reliable, simple in design and operate with no noise or vibration. Diffusion pumps are still the most economical means for creating high-vacuum pressures. Diffusion pumps also tolerate operating conditions such as excess particles and reactive gases that would destroy other types of high-vacuum pumps. They can be ordered with a 3-phase 208, 240, 380, 480 VAC heater harness and with standard or extended cold cap. We stock and sell Santovac 5 diffusion pump fluids for this pump. Please see below in our “Related” section for additional accessories that may benefit your vacuum applications and maintenance needs. We offer a large variety of vacuum greases, oils, vacuum fittings, hoses, vacuum gauges, sensors/transducers, parts and accessories sold separately on this website. These Agilent Varian VHS-400 diffusion pumps have ISO 400K no bolt inlet flange, operate on 3-phase 208 VAC, standard cold cap and has Agilent Varian part number L9767307. The Agilent Varian VHS-400 diffusion pump user’s instruction manuals can be downloaded in PDF format below. These are typical stock items that often ship same day as order is placed.

Agilent Varian VHS-400 Water Cooled Vacuum Diffusion Pump, ISO400K Inlet Flange, 17.72 inch OD, Maximum Pumping Speed 8000 l/s Air Standard Cold Cap, (2) 240 VAC 2200 Watt Heaters, Agilent Varian Part Number L9767308. The Agilent Varian VHS-400 has been designed to fill a special need in applications where high pumping speeds are required and space limitations demand a compact pump. The VHS-400 pump is a rugged, general-purpose unit with an operating range of 1.4 x 10-3 to <5 x 10-9 Torr at 4400W. The Agilent Varian VHS-400 is ideal for applications requiring fast cycling because of its high pumping speed (maximum rated at 8000 l/s with standard cold cap) air combined with high forepressure tolerance (0.65 Torr with no-load and 0.55 Torr when at full gas load). Backstreaming rate of the unit is 1x10-3 mg/cm2/ min, without the use of any cooled cold cap. This Agilent Varian VHS-400 Diffusion Pump Includes: ISO 400K (17.72 in. OD) No bolt holes ISO 63K (3.75 in. OD) No bolt holes Standard Cold Cap Recommended Roughing Backing Pump: 30 CFM 8000 l/s Maximum Pumping Speed Air 240 VAC 3 ph (4400W) with (2) 2200 Watt Heaters Water Connections 1/8 in. FPT Tee Designed To Be Used With Santovac 5 or IVP 704 Diffusion Pump Oil, 1000cc (1.056 Qt.) full charge Diffusion pumps use a high-speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the outlet. The oil diffusion pump is operated with an oil that has low vapor pressure. Its purpose is to achieve higher vacuum (lower pressure) than possible by use of positive displacement pumps alone. The Agilent Varian VHS-400 can pump down to pressures of <5x10-9 Torr. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump, roughing pump is typically used to maintain an outlet pressure around 1 mTorr. These Agilent Varian Diffusion Pumps are very reliable, simple in design and operate with no noise or vibration. Diffusion pumps are still the most economical means for creating high-vacuum pressures. Diffusion pumps also tolerate operating conditions such as excess particles and reactive gases that would destroy other types of high-vacuum pumps. They can be ordered with a 3-phase 208, 240, 380, 480 VAC heater harness and with standard or extended cold cap. We stock and sell Santovac 5 diffusion pump fluids for this pump. Please see below in our “Related” section for additional accessories that may benefit your vacuum applications and maintenance needs. We offer a large variety of vacuum greases, oils, vacuum fittings, hoses, vacuum gauges, sensors/transducers, parts and accessories sold separately on this website. These Agilent Varian VHS-400 diffusion pumps have ISO 400K no bolt inlet flange, operate on 3-phase 240 VAC, standard cold cap and has Agilent Varian part number L9767308. The Agilent Varian VHS-400 diffusion pump user’s instruction manuals can be downloaded in PDF format below. These are typical stock items that often ship same day as order is placed.

Agilent Varian VHS-400 Water Cooled Vacuum Diffusion Pump, ISO400K Inlet Flange, 17.72 inch OD, Maximum Pumping Speed 8000 l/s Air Standard Cold Cap, (2) 380 VAC 2200 Watt Heaters, Agilent Varian Part NumberL9767326. The Agilent Varian VHS-400 has been designed to fill a special need in applications where high pumping speeds are required and space limitations demand a compact pump. The VHS-400 pump is a rugged, general-purpose unit with an operating range of 1.4 x 10-3 to <5 x 10-9 Torr at 4400W. The Agilent Varian VHS-400 is ideal for applications requiring fast cycling because of its high pumping speed (maximum rated at 8000 l/s with standard cold cap) air combined with high forepressure tolerance (0.65 Torr with no-load and 0.55 Torr when at full gas load). Backstreaming rate of the unit is 1x10-3 mg/cm2/ min, without the use of any cooled cold cap. This Agilent Varian VHS-400 Diffusion Pump Includes: ISO 400K (17.72 in. OD) No bolt holes ISO 63K (3.75 in. OD) No bolt holes Standard Cold Cap Recommended Roughing Backing Pump: 30 CFM 8000 l/s Maximum Pumping Speed Air 380 VAC 3 ph (4400W) with (2) 2200 Watt Heaters Water Connections 1/8 in. FPT Tee Designed To Be Used With Santovac 5 or IVP 704 Diffusion Pump Oil, 1000cc (1.056 Qt.) full charge Diffusion pumps use a high-speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the outlet. The oil diffusion pump is operated with an oil that has low vapor pressure. Its purpose is to achieve higher vacuum (lower pressure) than possible by use of positive displacement pumps alone. The Agilent Varian VHS-400 can pump down to pressures of <5x10-9 Torr. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump, roughing pump is typically used to maintain an outlet pressure around 1 mTorr. These Agilent Varian Diffusion Pumps are very reliable, simple in design and operate with no noise or vibration. Diffusion pumps are still the most economical means for creating high-vacuum pressures. Diffusion pumps also tolerate operating conditions such as excess particles and reactive gases that would destroy other types of high-vacuum pumps. They can be ordered with a 3-phase 208, 240, 380, 480 VAC heater harness and with standard or extended cold cap. We stock and sell Santovac 5 diffusion pump fluids for this pump. Please see below in our “Related” section for additional accessories that may benefit your vacuum applications and maintenance needs. We offer a large variety of vacuum greases, oils, vacuum fittings, hoses, vacuum gauges, sensors/transducers, parts and accessories sold separately on this website. These Agilent Varian VHS-400 diffusion pumps have ISO 400K no bolt inlet flange, operate on 3-phase 380 VAC, standard cold cap and has Agilent Varian part number L9767326. The Agilent Varian VHS-400 diffusion pump user’s instruction manuals can be downloaded in PDF format below. These are typical stock items that often ship same day as order is placed.

Agilent Varian VHS-400 Water Cooled Vacuum Diffusion Pump, ISO400K Inlet Flange, 17.72 inch OD, Maximum Pumping Speed 8000 l/s Air Standard Cold Cap, (2) 480 VAC 2200 Watt Heaters, Agilent Varian Part NumberL9767309. The Agilent Varian VHS-400 has been designed to fill a special need in applications where high pumping speeds are required and space limitations demand a compact pump. The VHS-400 pump is a rugged, general-purpose unit with an operating range of 1.4 x 10-3 to <5 x 10-9 Torr at 4400W. The Agilent Varian VHS-400 is ideal for applications requiring fast cycling because of its high pumping speed (maximum rated at 8000 l/s with standard cold cap) air combined with high forepressure tolerance (0.65 Torr with no-load and 0.55 Torr when at full gas load). Backstreaming rate of the unit is 1x10-3 mg/cm2/ min, without the use of any cooled cold cap. This Agilent Varian VHS-400 Diffusion Pump Includes: ISO 400K (17.72 in. OD) No bolt holes ISO 63K (3.75 in. OD) No bolt holes Standard Cold Cap Recommended Roughing Backing Pump: 30 CFM 8000 l/s Maximum Pumping Speed Air 480 VAC 3 ph (4400W) with (2) 2200 Watt Heaters Water Connections 1/8 in. FPT Tee Designed To Be Used With Santovac 5 or IVP 704 Diffusion Pump Oil, 1000cc (1.056 Qt.) full charge Diffusion pumps use a high-speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the outlet. The oil diffusion pump is operated with an oil that has low vapor pressure. Its purpose is to achieve higher vacuum (lower pressure) than possible by use of positive displacement pumps alone. The Agilent Varian VHS-400 can pump down to pressures of <5x10-9 Torr. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump, roughing pump is typically used to maintain an outlet pressure around 1 mTorr. These Agilent Varian Diffusion Pumps are very reliable, simple in design and operate with no noise or vibration. Diffusion pumps are still the most economical means for creating high-vacuum pressures. Diffusion pumps also tolerate operating conditions such as excess particles and reactive gases that would destroy other types of high-vacuum pumps. They can be ordered with a 3-phase 208, 240, 380, 480 VAC heater harness and with standard or extended cold cap. We stock and sell Santovac 5 diffusion pump fluids for this pump. Please see below in our “Related” section for additional accessories that may benefit your vacuum applications and maintenance needs. We offer a large variety of vacuum greases, oils, vacuum fittings, hoses, vacuum gauges, sensors/transducers, parts and accessories sold separately on this website. These Agilent Varian VHS-400 diffusion pumps have ISO 400K no bolt inlet flange, operate on 3-phase 480 VAC, standard cold cap and has Agilent Varian part number L9767309. The Agilent Varian VHS-400 diffusion pump user’s instruction manuals can be downloaded in PDF format below. These are typical stock items that often ship same day as order is placed.

Agilent Varian VHS-400 Diffusion Pump Replacement Standard Cold Cap. Agilent Varian PN K4823301. These Agilent Varian VHS-400 diffusion pump standard cold caps are a replacement part that can be installed at the customer's location. There are two types of cold caps, standard and extended. The type of cold cap used will influence factors, such as, oil backstreaming and final pumping speed of the diffusion pump. For example, the Extended Cold Cap is an option that fits inside the VHS-400 pumps in place of the standard cold cap. It stops backstreaming as effectively as an optically dense baffle, yet it retains 80% of the pump’s speed. Residual backstreaming is so low that it cannot be measured by the American Vacuum Society’s standard collection method. For location of the cold cap please see item #1 on diagram exploded view & parts illustration shown below. For removal installation procedures of cold cap see page 41 of instruction manual PDF below. These standard cold caps are OEM original Agilent Varian replacement parts with part number K4823301.

Agilent Varian VHS-400 Jet Assembly Diffusion Pump Replacement Part Agilent Varian Part Number F0428401 These Agilent Varian VHS-400 diffusion pump jet assemblies are OEM Agilent Varian replacement parts for the VHS-400 diffusion vacuum pumps. This kit includes the complete jet assembly components, see the jet assembly referenced in Page 42 in instruction manual PDF below. These are original OEM Agilent Varian replacement parts for the VHS-400 diffusion pump having part number F0428401, see item #2 in the diagram exploded view & parts illustration below.

Agilent Varian VHS-400 Splash Baffle Diffusion Pump Replacement Part Agilent Varian Part Number F0431301 These Agilent Varian VHS-400 diffusion pump splash baffle part, it is part of the jet assembly and is a OEM Agilent Varian replacement part for the VHS-400 diffusion vacuum pump. See referenced on Page 42 in instruction manual PDF below. These are original OEM Agilent Varian replacement parts for the VHS-400 diffusion pump having part number F0431301, see item #4 in the diagram exploded view & parts illustration below.

Agilent Varian VHS-400 Jet Coupling Diffusion Pump Replacement Part Agilent Varian Part Number L6367301 These Agilent Varian VHS-400 diffusion pump jet coupling part, it is part of the jet assembly and is a OEM Agilent Varian replacement part for the VHS-400 diffusion vacuum pump. See referenced on Page 42 in instruction manual PDF below. These are original OEM Agilent Varian replacement parts for the VHS-400 diffusion pump having part number L6367301, see item #5 in the diagram exploded view & parts illustration below.

Agilent Varian VHS-400 Foreline Baffle Assembly, Diffusion Pump Replacement Parts Agilent Varian Part Number F0435301 These Agilent Varian VHS-400 diffusion pump replacement foreline baffle assemblies are OEM Agilent Varian replacement parts with part number F0435301. The foreline baffle is located in the roughing line exhaust arm of the diffusion pump. They are designed to help prevent diffusion pump oil from being transported to the roughing pump under high throughput conditions. See the VHS-400 diffusion pump roughing line arm noted by balloon #5 in the illustration below.

Agilent Varian VHS-400 Oil Sight Glass Kit, Diffusion Vacuum Pump Replacement Parts Agilent Varian Part Number L8908301. This is a replacement Sight Glass Kit. Fits the Agilent Varian VHS-400 Diffusion Pump. For location of the sight glass kit see item #3 on (diagram exploded view & parts illustration) below.

Agilent Varian Replacement O-Ring Kit for the VHS-400 Diffusion Pump, ASA 18 in. OD. PN K0377189. These O-Ring kits fit the Agilent Varian VHS-400, ASA 18 inch OD Non Standard, Diffusion Pump. Other diffusion pump accessories are available on this web site. O-Ring Kit Contains: 1 Inlet Flange O-Ring ASA Non Standard Butyl No. 2-385 1 Foreline Outlet Flange O-Ring ASA 2 in. Butyl No. 2-338 10 Viton fill and drain O-rings (old style), Parker No. 2-112 10 Viton fill and drain O-rings (new style, Parker No. 2-113 1 PTFE gasket 1 Sight glass O-ring, Parker No. 2-226

Agilent Varian VHS-10 and VHS-400 Oil Drain Plug, Diffusion Vacuum Pump Replacement Parts. Agilent Varian Part Number: L9173001. This is a replacement Oil Drain Plug. Fits the Agilent Varian VHS-10 and VHS-400 Diffusion Pump. For location of the oil drain plug see figure #7 (diagram exploded view & parts illustration) below.

Agilent Varian VHS-400 Diffusion Pump Heater Insulator, Replacement Part, For New Style Diffusion Pumps Agilent Varian Part Number L8914001 These Agilent Varian VHS-400 diffusion pump heater insulator covers are used to insulate the heater from pumps bottom cover. These heater insulators are used in the new-style diffusion pumps. These are OEM Agilent Varian replacement parts with part number L8903301, see item #13 below in illustration for heater insulator location.

Agilent Varian VHS-400 Diffusion Pump Heater Wire, 10 AWG, Sold by the foot This is the Agilent Varian VHS-400 Diffusion Pump stranded nickel heater wire, 10 AWG, Sold by the foot. (3 - 42 inch lengths required for total replacement per pump). See No. 8 below in illustration for heater wire location.

Agilent Varian VHS-400 Diffusion Pump Heater Wire Kit, 10 AWG Wire, 15 ft. length with Molex and Terminal Lugs. PN L8913301 This is the Agilent Varian VHS-400 Diffusion Pump stranded nickel heater wire kit, 10 AWG wire (15ft.) Terminal Strip Molex, and 10 lugs. See No. 8 below in illustration for heater wire location.

Agilent Varian Thermal Switch for VHS-4, 6,10, 250, & 400 Diffusion Pumps PN 642906025 This is the Agilent Varian VHS-4, VHS-6, VHS-10, VHS-250, VHS-400 Diffusion Pump replacement Thermal Switch. (Set at 300º F, 148º C). See No. 15 below in illustration for thermal switch location on a VHS-4

Agilent Varian VHS-400, Diffusion Pump Thermal Switch Kit. Agilent Varian PN L8912301 This is a Thermal Switch Kit. Fits the Agilent Varian VHS-400 Diffusion Pump. For location of the baffle retaining ring see item #7 on (diagram exploded view & parts illustration) below. This Thermal Switch Kit includes: Thermal Switch Lug Wire Box Insulator

Agilent Varian VHS-400 Crush Plate for Varian Diffusion Pumps. Varian Agilent Part Number K7667001 These Agilent Varian VHS-400 diffusion pump crush plates are for Agilent Varian diffusion vacuum pumps. The crush plate is required during heater replacement. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Heater Cover Plate, PN L8903301 (sold as one each) These Agilent Varian VHS-400 Heater Cover Plate. The Agilent Varian part number for this is L8903301 and its location is item #13 in graphic diagram and description below. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump SLOTTED Clamping Plate, PN R2667301 (sold as one each) These Agilent Varian VHS-10 are SLOTTED retrofit clamping plates. The Agilent Varian part number for this is R2667301 and its location is item #12 in graphic diagram and description below. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS-400 Diffusion Pump Heater Clamping Plate A36 Steel, PN K4928001 (sold as one each) These Agilent Varian VHS-400 are A36 steel heater clamping plates. The Agilent Varian part number for this is K4928001 and its location is item #11 in graphic diagram and description below. Other diffusion pump accessories are available on this web site.

Agilent Varian Bolts to Attach ASA Gate Valves to ASA Diffusion Pumps 3/4-10 1-1/4" Length Hex Bolt - Course Thread, 1 each. These are bolts to attach ASA Gate Valves to ASA Diffusion pumps, ASA sizes 6, 8 and 10 inch. One each, size 3/4-10 1-1/4" Length Hex Bolt - Course Thread.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 480VAC, 2200W, 4.6A, 104 Ohms, Per Heater, PN 647310170 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 480 VAC input power. These heaters pull 2200 Watts, 4.6 Amps and have a room temperature resistance of 104 Ohms. These heaters are designed to be operated by 480 VAC, two heaters are required for (4400 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310170. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 208VAC, 2200W, 10.6A, 19.6Ohms, Per Heater, PN 647310140 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 208 VAC input power. These heaters pull 2200 Watts, 10.6 Amps and have a room temperature resistance of 19.6 Ohms. These heaters are designed to be operated by 208 VAC, two heaters are required for (4400 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310140. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 208VAC, 2550W, 12.2A, 17 Ohms, Per Heater, PN 647310145 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 208 VAC input power. These heaters pull 2550 Watts, 12.2 Amps and have a room temperature resistance of 17 Ohms. These heaters are designed to be operated by 208 VAC, two heaters are required for (5100 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310145 and its location is item #10 in graphic diagram and description below. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 240VAC, 2200W, 9.2A, 26 Ohms, Per Heater, PN 647310150 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 240 VAC input power. These heaters pull 2200 Watts, 9.2 Amps and have a room temperature resistance of 26 Ohms. These heaters are designed to be operated by 240 VAC, two heaters are required for (4400 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310150. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 240VAC, 2550W, 10.6 A, 22.6 Ohms, Per Heater, PN 647310155 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 240 VAC input power. These heaters pull 2550 Watts, 10.6 Amps and have a room temperature resistance of 22.6 Ohms. These heaters are designed to be operated by 240 VAC, two heaters are required for (5100 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310155 and its location is item #10 in graphic diagram and description below. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 380VAC, 2200W, 5.8A, 66 Ohms, Per Heater, PN 647310160 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 380 VAC input power. These heaters pull 2200 Watts, 5.8 Amps and have a room temperature resistance of 66 Ohms. These heaters are designed to be operated by 380 VAC, two heaters are required for (4400 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310160. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 380VAC, 2550W, 6.7A, 56.6 Ohms, Per Heater, PN 647310165 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 380 VAC input power. These heaters pull 2550 Watts, 6.7 Amps and have a room temperature resistance of 56.6 Ohms. These heaters are designed to be operated by 380 VAC, two heaters are required for (5100 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310165 and its location is item #10 in graphic diagram and description below. Other diffusion pump accessories are available on this web site.

Agilent Varian VHS400 Diffusion Pump Tubular Heater 480VAC, 2550W, 5.3A , 90.4 Ohms, Per Heater, PN 647310175 (sold as one each) These Agilent Varian VHS-400 diffusion vacuum pump Tubular-Style replacement heaters are for use with 480 VAC input power. These heaters pull 2550 Watts, 5.3 Amps and have a room temperature resistance of 90.4 Ohms. These heaters are designed to be operated by 480 VAC, two heaters are required for (5100 Watts of heating power). For heater assembly replacement instructions see page 43 in the instruction manual .pdf below. The Agilent Varian part number for this heater is 647310175 and its location is item #10 in graphic diagram and description below. Other diffusion pump accessories are available on this web site.