Over the years we have noted some questions come up time and time again.
We have listed some of the most common questions for your reference.
As time moves, we will add further examples.
| TH Witt |
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| GP Pump repairs - seal leak | |
| Q | Can I only replace one seal? |
| A | No because the gas leak appears at the shaft end but the shaft will need two seals when opened up. |
| GP gas locking - no vent line | |
| Q | The pump will not deliver head and appears gas locked? |
| A | The vent line from the discharge valve must be installed correctly. - Vertical run only, not horizontal - EE6 vent valve to be ½ turn open - Each pump to have its own vent line |
| GP replacement type of oil | |
| Q | Can I use compressor oil in the GP pump oil reservoir? |
| A | No. You can use any oil having the correct low temperature pour point 10°C below the lowest evaporating temperature. |
| Q | What will happen if I use the wrong oil? |
| A | The Teflon pump seals will not be lubricated correctly if the wrong oil is used due to the waxing (increased viscosity) of the oil. |
| HRP Pumps Difference in models. |
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| Q | I have an old HRP type Witt Hermetic Pump. What is the difference from the current model? |
| A | The HRP Pump models HRP5040 and HRP8050 were originally supplied with a thermal cut out switch which sensed the temperature of the transformer oil around the motor. The cut off temperature is +50°C.
The new HRP pump models HRP3232, 5040, 5050, 8050 and 100:80 are all fitted with an internal high temp sensor inside the motor winding. This sensor is connected to an INT69V single controller in the electrical control panel. Titan currently stocks only the new model with the windings sensor. It is still possible to obtain replacement HRP pumps with the thermal cut-out as a special order to the Witt factory. |
| Robinet Refrigeration Valves |
|
| Closing shut off valves | |
| Q | How can I tell if the valve is closed. When using a spanner, I do not feel any resistance? |
| A | The Robinet valve uses a PTFE seat with a 45° chamfered face closing against a 45° machined face.
Each hand wheel shut off valve should only be closed by finger pressure. This we have witnessed was sufficient to hold close a valve against a test pressure of 75 bar. If you use a spanner to close the valve or to constantly re seat the valve closed, you can damage and deform the PTFE material. In extreme cases we know customers who keep turning the valve closed until only the valve metal seat holder is in contact with the 45° |
| Valve does not feel closed | |
| Q | When closing the Robinet shut off valve it does not feel tight? |
| A | The valve should be closed using the correct size valve handle. The force required across the range is only finger tight for small valves, hand tight for large valves. It is not recommended to use a spanner to close the valves as the Teflon seat material will deform if overtightened. The Teflon can be pushed off the metal seat holder if the operator uses a spanner and does not realise the Teflon is yielding. A finger tight closing is sufficient to close against 75 bar. |
| Positioning | |
| Q | Can I install a Robinet valve upside down? |
| A | No, the only position allowed is at 9, 12 and 3 o’clock. It is not allowed to install the valve upside down with the spindle facing downwards. |
It is important that refrigeration engineers read and are familiar with the manufacturer’s instruction books/sheets at all times.
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Titan Engineering is a long-standing member of the British Refrigeration Association, with a reputation for professionalism throughout industry. It is supportive of high standards and quality, which it promotes by active participation in a range of association activities, alongside willing support for the Institute of Refrigeration. These contributions to the collective good of the sector reinforce the high regard in which Titan is held amongst its peers. CEDRIC SLOAN |
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