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-4 Diffusion Pump Replacement Heater, 1450W, 208 VAC. Agilent Part Number: 647304210. This is a replacement heater for the Agilent Varian VHS-4 Air Cooled Diffusion Pump, 1450W, 208 VAC. 1 heater required per pump.

Agilent Varian VHS-4 Diffusion Pump Replacement Heater, 1450W, 240 VAC. Agilent Part Number: 647304250. This is a replacement heater for the Agilent Varian VHS-4 Air Cooled Diffusion Pump, 1450W, 240 VAC. 1 heater required per pump.

Agilent Varian VHS-4 Diffusion Pump Heater Insulator, Replacement Part, For New Style Diffusion Pumps.Agilent Varian Part Number 86087001. These Agilent Varian VHS-4 diffusion pump heater insulators 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 86087001, see #11b below in illustration for heater insulator location.

Agilent Varian VHS-4 Air Cooled Diffusion Pump Heater Clamp PN 88164301 This is a replacement heater clamp for the Agilent Varian VHS-4 Air Cooled Diffusion Pump. 1 required per pump.

Agilent Varian VHS-4 Sight Glass Repair Kit, Diffusion Pump Replacement Parts Agilent Varian Part Number L8908301 These Agilent Varian VHS-4 oil sight glass kit are OEM Agilent Varian replacement parts and have part number L8908301. This kit fits the new modern style VHS-4 model diffusion vacuum pumps. The parts for this kit are shown in item #17 in the illustration below.

Agilent Varian VHS-4 Air Cooled Diffusion Pump replacement O-Ring Kit (for ASA4 inch inlet) K0377183 PN K0377183 Agilent Varian VHS-4 Air Cooled Diffusion Pump replacement O-Ring Kit (for ASA4 inch inlet). O-Ring Replacement Kit Contains: 3 - Inlet Flange O-Rings (butyl 2-258) rubber 10 - Fill and Drain O-Rings Old Style (Viton 2-113) rubber 10 - Fill and Drain O-Rings New Style (Viton 2-113) rubber 1- Sight Glass O-Ring and Gasket no. 2-226 1- PTFE Gasket

Agilent Varian VHS-4 Ceramic Insulator for Cold Cap, Diffusion Pump Replacement Part Agilent Varian Part Number 699006025 These Agilent Varian VHS-4 ceramic insulators are OEM Agilent Varian replacement parts for the VHS-4 diffusion vacuum pumps, having Agilent Varian part number 699006025. These ceramic insulators are used as a spacer between the jet assembly and the cold cap (please see the center photograph above and item #20 in the illustration below).

Agilent Varian VHS-4 Extended Cold Cap, Mexican Hat, Diffusion Vacuum Pump Replacement Parts Agilent Varian Part Number F6898301 These Agilent Varian VHS-4 extended cold caps are OEM Agilent Varian replacement parts for the VHS-4 diffusion vacuum pumps. The extended cold cap is sometimes referred to as a Mexican Hat due to its shape. 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-4, VHS-6, and VHS-10 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 removal installation procedures of cold cap see page 37 of instruction manual PDF below. These extended cold caps are OEM original Agilent Varian replacement parts with part number F6898301, see item #16 on (diagram exploded view & parts illustration) below.

Varian VHS-4, VHS-6 and VHS-250 Old-Style Diffusion Vacuum Pump Bottom Heater Cover These Varian Varian VHS-4, VHS-6 and VHS-250 diffusion vacuum pump replacement bottom heater covers are made of Aluminum and are direct replacements. The heater cover protects the bottom of the diffusion pump and the heater assemble. Other diffusion pump accessories are available on this web site.

Varian VHS-4 Old-Style Diffusion Pump Thermal Overload Switch Aluminum Cover Box These Varian VHS-4 diffusion vacuum pump replacement thermal overload switch covers are made of aluminum. They also include the replacement mounting hardware. The thermal switch is used to protect the diffusion pump from over heating which typically occurs from lack of cooling water.

Agilent Varian VHS-6 & VHS-4 Diffusion Pump Replacement Standard Cold Cap. Agilent Varian PN 86488301 These Agilent Varian VHS-6 and VHS-4 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-4, VHS-6, and VHS-10 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 37 of instruction manual PDF below. These standard cold caps are OEM original Agilent Varian replacement parts with part number 86488301.