1.   Replacement of the electrical wiring and heating systems, and refurbishment of the lift, were completed on time.

2.   The gas leak was caused by a faulty heating system.

3.   The heating system is old, somewhat noisy, largely uncontrolled and difficult to re-light.

4.   The heating system runs on oil.

5.   The heating system was barely adequate.

6.   The heating system would only be adequate for a much smaller house.

7.   The landlord has promised to put in a new heating system.

8.   The new heating system is certainly an improvement on the old one.

9.   The substantial remains of the cavalry fort include a bath house showing the sophisticated workings of the underfloor heating system.