On Bitzer's EST-600 series page, the oil level at standstill should be at least half of the sight glass, and ideally two-thirds after you add oil. A single compressor that is running can be at a minimum of one quarter of the glass. Those values are for the EST-600 series, so confirm them for your compressor series.
Oil level in the sight glass (Bitzer EST-600 series page)
| Condition | Level Bitzer gives |
|---|---|
| Standstill | At least 1/2 of the sight glass; ideally 2/3 after adding oil |
| Running, single compressor | Minimum 1/4 of the sight glass is acceptable |
| Primary compressor in a tandem or trio (the page's "BAHT primary" case) | Bottom of the glass is admissible |
The table is Bitzer's wording, condensed. For the tandem and trio case, read the page for the exact conditions that "BAHT primary" covers. We do not interpret it.
Reading the figures correctly
The page gives a separate figure for standstill and for running, so a reading means nothing until you note which condition you took it in. A level taken at standstill is compared to the standstill figure. A level taken while running is compared to the running figure.
The page also gives a target as well as a floor. At standstill, at least one half is the floor, and two thirds after adding oil is the ideal. The running figure of one quarter is a minimum for a single compressor, not a target to fill to.
How to check the level
- Identify the compressor series on the nameplate. The values above are from the EST-600 series page. Confirm they apply to your compressor, and use the documentation for your series if they do not.
- Read the glass at standstill. Compare it to the standstill figure: at least one half.
- Read the glass while running. For a single compressor, compare it to the running figure: a minimum of one quarter.
- For a tandem or trio, read the page's primary-compressor wording. Do not apply the single-compressor figure to the primary compressor in that arrangement.
- If you add oil, use only Bitzer-approved oil. Bitzer's page says to use only oils it approves. Check Bitzer's approved-oil information for your compressor. Aim for the ideal of two thirds at standstill.
- Record the reading. Note the date, whether the compressor was stopped or running, and the level, so the next reading has something to compare against.
Steps 2, 3 and 5 use Bitzer's figures and wording from the EST-600 page. Steps 1, 4 and 6 are generic trade practice and add no numbers of their own. Where the page and your compressor's own documentation differ, follow the compressor's documentation.
Commissioning sequence for the oil level
The EST-600 page gives a sequence for commissioning, in this order:
- Oil heater on at least 12 hours before startup.
- One hour at nominal.
- Five minutes to settle.
- Recheck the oil level.
The page's wording for "nominal" is Bitzer's. Read the page for what it refers to before you apply the sequence on a job.
If the level is outside the figures
Do not simply top up and walk away. Note the condition you read it in, whether the compressor is stopped or running, and how long it has been since the last start. Then check that the oil heater circuit is energized as your wiring diagram shows. The pages we worked from give no cause list for a low or high level, so we do not offer one. Use Bitzer's documentation for your compressor, or contact us with the model, serial number and your readings.
The oil heater
Bitzer's technical information says an oil heater, an accessory, is required in customary applications to stop refrigerant dissolving in the oil while the compressor is at standstill. Bitzer's KT-600 page adds that a temperature-dependent control of the oil heater clearly reduces the energy requirement, and the EST-600 page gives the 12-hour pre-start figure above.
The pages we worked from give no heater wattage and no heater part number, so we print neither. Use your compressor's documentation or the label on the existing heater. In Protection Mode (SE-B), the CM-RC-02 does not control the oil heater; our CM-RC-02 article covers that mode.
If the compressor is discontinued
Bitzer's FAQ says a discontinued compressor can often be easily replaced by a current model. It points to two technical information documents: AT-310 for common replacement cases, and AT-320 for connections, valves and flanges. Start there with the full model from the nameplate. We do not state specific substitutions.
Our Bitzer listings are GSD-series and GSK-series scroll compressors with York numbers. If your compressor is a different Bitzer model, ask us before assuming we list a successor, and send the nameplate photo with your request.
What to send us
- The compressor model and serial number from the nameplate
- The sight glass reading, with the condition (stopped or running)
- Whether the unit is a single compressor, a tandem or a trio
- The oil in use, if it is marked on the compressor or in the service record
Oil-circuit parts
| Component | Role in this issue | Where to find it |
|---|---|---|
| Sight glass | Where the oil level is read | Send the compressor model and serial number through the request a quote page |
| Oil heater (accessory) | Keeps refrigerant from dissolving in the oil at standstill | Send the compressor model and heater details through contact |
| Bitzer compressor | The compressor the level is read on | Bitzer Compressors |
| Chiller compressors | Compressors across brands | Chiller Compressors |
| York chiller oils | York-branded oils for York equipment; not a Bitzer approved-oil list | York Chiller Compressor Oil & Chemicals |
Scope: The sight glass levels and the commissioning sequence come from Bitzer's EST-600 page, which covers the ORBIT 6 and ORBIT 8 scroll compressors in single, tandem and trio arrangements. We have not checked those values for other Bitzer series, and we do not state which of our listed GSD and GSK models they cover. Bitzer's own documents for your series govern. The heater statements come from the EST-600 and KT-600 pages, and the discontinued-model note from Bitzer's FAQ.
Before you order
Confirm your compressor's exact model and serial number from its nameplate before ordering. Our guide to finding the correct part from the model and serial number covers what to record. Browse our Bitzer compressors collection and the chiller compressors collection, and use the request a quote page for items we do not list by title. To confirm fit, contact us or email help@totalhvacparts.com with your model and serial number.
Frequently Asked Questions
How full should a Bitzer compressor sight glass be?
On the EST-600 series page, at least half the glass at standstill, ideally two thirds after adding oil. A single compressor running can be at a minimum of one quarter. Confirm the figures for your compressor series.
What is the Bitzer oil level running versus at standstill?
Standstill: at least one half of the sight glass. Running, single compressor: a minimum of one quarter is acceptable. The EST-600 page gives separate figures, so note which condition you read.
How long should the Bitzer oil heater be on before start?
The EST-600 page gives at least 12 hours before startup at commissioning. Bitzer says an oil heater, an accessory, is required in customary applications to stop refrigerant dissolving in the oil at standstill.
What is the oil level for a Bitzer tandem compressor?
For the primary compressor in a tandem or trio, the EST-600 page allows the bottom of the glass. It calls this the "BAHT primary" case. Read the page for the exact conditions before applying it.
Sources
- Bitzer technical information EST-600, oil level and commissioning page
- Bitzer technical information KT-600, oil heater page
- Bitzer FAQ, replacing a discontinued compressor (references AT-310 and AT-320)
Compressor service involves line-voltage electrical components, refrigerant under pressure, hot surfaces and rotating equipment. Service should be performed only by qualified personnel, following Bitzer's documentation for your compressor and your facility's lockout/tagout procedures.