This part fits the following boilers:
| Fits Appliance(s) | GC No. | |
| Worcester Highflow 400 BF | - | 47-311-19 |
| Worcester Highflow 400 BF LPG | - | 47-311-22 |
| Worcester Highflow 400 Of | - | 47-311-20 |
| Worcester Highflow 400 Of LPG | - | 47-311-23 |
| Worcester Highflow 400 RSF | - | 47-311-18 |
| Worcester Highflow 400 RSF LPG | - | 47-311-21 |