Teledyne 4220 Maintenance and Service, Minor Service, Case, Damage

4220 Flow Meter

Section 6 Maintenance and Service

6.1Routine Maintenance The following sections provide routine maintenance and ser-

and Minor Service	vicing instructions. Included are sections on cleaning the flow
	meter, reactivating the desiccators, maintaining the bubble line,
	servicing the internal printer, elementary troubleshooting and
	servicing CMOS circuitry.
	Teledyne Isco recommends that you become familiar with the
	maintenance procedures presented here. While the 4220 is rug-
	gedly built to withstand severe field conditions, it will function
	best and remain most reliable if you follow these simple proce-
	dures.

6.1.1Care of the Flow Meter If you close and latch the lid, and cap all the M/S connectors on

Case	the side of the case tightly, you can clean the case by spraying it
	with a hose or washing it with soapy water. Do not use a hose
	with a nozzle or a high pressure hose-and-wand. Do not immerse
	the flow meter in a tank of water to wash it. The flow meter can
	usually withstand accidental submersion in water, if that should
	occur, but it is not intended for routine submersion.

6.1.2Care of the Case Seal From time to time you should inspect the case seal and clean it, if necessary. The ridge around the edge of the case and the groove on the cabinet door form a seal when the door is closed. Keep this seal free of dirt, sand, etc. If it isn't, clean it carefully with a damp cloth. Also keep the rubber gasket in the lid clean. You can clean it with a small brush and a damp cloth. If you do any cleaning while the case is open, be careful not to let any dirt or debris fall inside the flow meter assembly. It is best to work on the flow meter with the case standing upright. If you don't maintain the seals properly, they may leak, causing damage and eventual failure of the components inside.

6.1.3Preventing Moisture To prevent moisture damage to the internal components, keep

Damage	the lid tightly latched at all times, except when it is necessary to
	change the program or change the chart. Do not operate the flow
	meter routinely with the case open. This will expose the internal
	components to dirt and moisture; it will also saturate the des-
	iccant canister inside the case very quickly. Inspect this canister
	periodically and recharge it as necessary as described subse-
	quently. It is also important to keep the external connectors clean
	by keeping the mating connectors or the protective caps tightly
	screwed down. Under severe operating conditions you can spray
	the threads of the connectors with a cleaner/lubricant such as Jif
	or WD-40 to prevent corrosion. Be careful not to spray any of the
	terminals (pins or jacks) inside the connectors; residue from the
	sprays could cause intermittent or failed connections.

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