Unit 316 Session 7 Testing and commissioning of hot water sys

​Testing and commissioning of   hot water systems  

​Documents required to carry out commissioning tasks 

 

Testing and commissioning of hot water systems is probably the most important part of any installation, as it is here that the system design is finally put into operation. For an installation to be successful the following documents must be complied with: 

 

• manufacturers’ instructions 

• job specification 

• Water Regulations 

• Building Regulations: Parts G, L and P 

 

Correct commissioning procedures and system set-up often make the difference between a system working to the specification and failing to meet the required demands. 

​Click on the link below and use the document along with the internet to answer the questions on the following pages:

​https://colegycymoedd.sharepoint.com/:b:/r/sites/Level3Year2Plumbing23.24/Shared%20Documents/Resources/Testing%20and%20commissioning%20of%C2%A0hot%20water%20systems%20.pdf?csf=1&web=1&e=7ilHke

Multiple Choice

What is the test pressure for plastic pipework? 

• 1 ½ times the working pressure 

• 2 times working pressure

• 1 times working pressure

• 3 times working pressure

Multiple Choice

What action should be carried out in the first stage of flushing an unvented domestic hot water system? 

• Fill storage cistern first

• Open the cold water supply and fill the storage vessel with water. 

• Only fill pipework

• Fill system with air

Multiple Choice

What documents must be used for successful installation commissioning?

• Operation manuals only

• Building Regulations only

• Water Regulations only

• Manufacturers’ instructions, job specification, Water Regulations, Building Regulations

Multiple Choice

Before soundness testing, what should be checked according to the manufacturers’ instructions?

• Ambient temperature

• Expansion vessel charge pressure

• Building height

Multiple Choice

What is the usual source for the initial system fill of fluid category 1 water?

• Rainwater harvesting

• Local river water

• Water undertaker’s main cold water supply

• Bottled water

Multiple Choice

How is the system filled during the initial fill process?

• Rapidly to save time

• In one stage

• Slowly in stages

Multiple Choice

Which British Standard describes the procedure for soundness testing hot water systems?

• BS6700

• BS7671

• BS5839

• BS5930

Multiple Choice

What is the requirement for flushing hot water systems according to British Standards?

• Optional

• Not necessary

• Mandatory

• Every 5 years

Multiple Choice

Why should hot water storage vessels and cold water storage cisterns be drained down completely during flushing?

• To save water

• To reduce system pressure

• To remove potential contaminants

• To clean the pipes

Multiple Choice

How often should unvented hot water storage systems be serviced?

• Every 6 months

• Every 12 months

• Every 2 years

• Every 5 years

Multiple Choice

What should be checked during the periodic servicing of unvented hot water systems?

• Water pressure in the neighbourhood

• Air quality

• Components, pressure in the expansion vessel, and cleaning the in-line strainer

• Outdoor temperature

Multiple Choice

Which document is most important for diagnostic checks on hot water systems?

• Local building codes

• Manufacturer’s instructions

• British Standards only

• Water Regulations

Multiple Choice

What do manufacturer’s instructions usually contain for fault-finding?

• Flow charts, symptoms, and replacement techniques

• No information on fault finding

• Telephone numbers of local engineers

• Spare part prices

Multiple Choice

In areas with hard water conditions, how often are inspections recommended for unvented hot water systems?

• Every 3 months

• Every 6 months

• Once a year

• Every 2 years

Multiple Choice

Which document takes precedence over British Standards and Regulations?

• Manufacturer’s instructions

• Local newspapers

• Commissioning records

• Sketches made during installation

Multiple Choice

What is the reason for more frequent inspections in hard water areas?

• Increased risk of limescale buildup

• High humidity

• Excessive rainfall

• Unstable atmospheric pressure

Multiple Choice

Why is it important to keep commissioning records for hot water systems?

• Decoration purposes

• To comply with local traditions

• To use as bookmarks

• For reference during maintenance and repair

Multiple Choice

When servicing an unvented hot water system it is found the thermal pressure valve is not releasing any water. What action should be taken?

• 1. Don’t do anything, as it is not under any pressure.

• 1. The blockage is only sediment and will clear when it overheats.

• Replace the valve making sure you fit the same bar type as the existing

• 1. Shut down the system and inform the manufacturer immediately.

Multiple Choice

The expansion-relief valve is dripping water when the system is cold and runs water when the system is on. Which one of the following is the most likely cause? 

• The system is overheating. 

• The expansion-relief valve is not seated properly. 

• The pressure-regulating valve has stopped working. 

• The strainer is blocked. 

Multiple Choice

The expansion-relief valve runs when the system is hot but is okay when the system is cold. Which one of the following is the most likely cause? 

• The expansion vessel needs recharging. 

• The thermostat is set too high. 

• The boiler thermostat is set too high. 

• The expansion relief valve is faulty. 

Multiple Choice

The expansion valve in an unvented hot water storage system is not working to specification when installed in a hard water area. Which one of the following is the most likely cause? 

• Build-up of calcium carbonate deposits. 

• Build-up of silt from within the system. 

• Faulty electrical supply to the valve.

• Inlet pressure is too high for the system. 

Multiple Choice

In indirect unvented system water from the mixer taps is running cold. One possible cause is: 

• high-pressure hot water surge from the cylinder. 

• expansion-relief valve is letting by. 

• hot and cold pressures at shower/mixer taps are unbalanced. 

• indirect thermal control cut-out has operated. 

Multiple Choice

In the unvented hot water system, shown below, a full flow of water and steam discharges from the temperature relief valve intermittently. Which two of the following components are likely to be faulty? 

• A and B 

• A and C 

• D and E 

• F and H 

Multiple Choice

The unvented cylinder has overheated the thermal expansion valve is blowing steam into the tundish. What action should be taken? 

• Turn off the water main. 

• Ring 999. 

• Drain down the system. 
   

• Turn off the source of heat. 

Multiple Choice

Which one of the following should be carried out before removing a motorised valve from an unvented cylinder?  

• Ensure the electricity supply has been safely isolated. 

• Open the expansion- and temperature-relief valves. 

• Drain the hot water supply through the tundish. 

• Ensure the expansion vessel is fully compressed. 

Multiple Choice

Which one of the following is the first activity that should be carried out when maintaining an unvented system? 

• Check for evidence of discharge from the relief valves. 

• Remove and clean the line strainer. 

• Notify the Water Supplier that maintenance is taking place. 

• Notify WRAS that maintenance work is taking place. 

Multiple Choice

In high-pressure systems containing mixer taps, the pressure reducing valve should be positioned so that: 

• the hot water pressure is higher at the mixer taps. 

• the cold water pressure is higher at the mixer taps. 

• both hot and cold water outlets are operating at the same pressure. 

• the pressure at the mixer taps exceeds the supply inlet pressure.