Energy upgrade specialists Eaga are responsible for technical training on SEAI’s Home Energy Saving scheme. Eaga technical manager Paul Wilson answers some key technical questions on the installation of boilers and heating arising from the recent contractor training.
Construct Ireland: How much pipe insulation is required to fit a cylinder during a boiler and heating controls upgrade?
Paul Wilson: Each pipe connected to a cylinder should be insulated for one linear metre in an attempt to retain as much heat as possible within the cylinder as a means of energy saving whilst producing hot water. The hot press or airing cupboard is no longer relevant as energy conservation is the key. The insulation should be glued and/or correct insulation tape used.
CI: Does an immersion heater timer need to be fitted on a controls upgrade?
PW: Yes, but only when an immersion heater and/or immersion heater circuit is already in situ. The timer should be rated for a 3kW immersion and have a 24 hour multi-setting capability.
CI: Does the immersion need to be changed on all jobs with a thermal cut-out?
PW: No, however, the client should be advised that in terms of health and safety, a new immersion should be considered and the contractor should offer an itemised price for this work.
CI: Describe the three Ts rule.
PW: The three Ts rule relates to an open vented system design and should be remembered as follows: on the flow from the boiler the first T is the vent, the second T is the cylinder connection and the third T is the radiators. On the return, again, the closest connection to the boiler, the first T is the cold feed, the second T is the cylinder connection and the third T is the radiators.
CI: Does the condensate pipe need to be lagged or the diameter of the pipe increased externally in all cases?
PW: Yes. No 22mm pipe work connected to the condensate drain should be exposed to the elements as this increases the risk of the pipe freezing under harsh weather conditions.
CI: Must the fire valve be at least one metre from the boiler?
PW: Yes. OFTEC refers to BS5410 for guidance and insists that this is adhered to. The standard is further referenced in TGD J for heat producing appliances.
CI: What do you do if you have an installation where it is difficult and seemingly impossible to get a new flow and return to a cylinder in order to provide separate hot water and central heating?
PW: In Eaga’s experience, nothing is impossible. It might be difficult and it might increase the cost of the job, but it is essential to separate hot water and central heating to comply with the Home Energy Saving scheme rules and ensure energy conservation.
CI: Why can’t you fit a room thermostat in a room with a TRV?
PW: The room stat is fitted in place of a TRV as a general control for the heating system. It is also an integral part of the boiler interlock. Fitting a TRV in this room – when not set at fully opened – will act against the room stat and may allow the heating system to overheat the rest of the property as the room where it is situated has not satisfied the temperature call of the room stat, because the radiator TRV has shut down. If the heating system has been designed properly, taking into consideration the industry recognised temperature requirements for each room, the system should work at its most efficient where the room with the room stat does not have a radiator with a TRV fitted.
CI: Where should a room stat be located?
PW: The stat should be located where it is not influenced by direct sunlight, draughts, secondary heat sources or above radiators. The hall or the living room is a satisfactory location assuming the radiator in the room in question has been correctly sized for that room.
CI: When pricing a job, should the existing state of the wiring be taken into account?
PW: Yes. Ultimately the installer is responsible for the installation which includes electrical safety. If there’s any doubt about the standard of the wiring, a qualified electrician should be consulted who can determine this and advise if additional electrical works need to be priced to ensure safety.
CI: The capillary/phial of a fire valve should be fixed in a position provided by the boiler manufacturer. Should it be the boiler manufacturer’s responsibility to provide such a fixing?
PW: This is a debate for the manufacturers to decide on. However as there is currently no consensus on this, it remains the contractor’s responsibility to ensure the fire valve will work under flame conditions and we will fail contractors who do not ensure the correct position of the remote fire valve. Incidentally, only remote acting fire valves are acceptable.