During winter months when it is particularly cold, condensation can form and freeze on the finned evaporator coil of the unit. It is a normal occurrence and the heat pump is designed to cope with this. The control system will detect when the coil has iced up and will automatically enter a ‘defrost’ cycle. During this short ‘defrost’ period the fan will stop and the heat pump will cease supplying heat to the heating system in order to melt the ice. On completion the fan and heat pump will automatically restart and resume supplying heat to the heating system. This will not adversely affect the building temperature.
Heat pumps use either one or two fans to draw air through the unit to extract the heat energy. These fans will produce a moderate sound level that might be perceived by some as a nuisance, either by the occupants of the building with the heat pump system, or the neighbours. In particular this may be a greater problem at night when background noise is much lower. Careful choice of the heat pump location can help to minimise or eliminate the potential nuisance, e.g. not too close to bedroom windows (particularly with a bungalow) or too close to a neighbour’s boundary or property. Two of our latest models, the Aerona³ R32 13kW and 17kW heat pumps have achieved the Quiet Mark, an accolade which recognises some of the quietest, high performing products in the market.
The coil of an existing cylinder will almost certainly be too small and this will result in longer cylinder reheat times at the lower water flow temperatures from a heat pump. For best performance a Grant High Performance cylinder should be used. This has a larger coil to reduce reheat times.
Heat pumps work very well with radiator circuits or mixtures on radiators and underfloor heating.
The primary flow temperature should be set at 50°C, to supply the radiators whereas the u/floor circuits will have a “blending valve” to decrease this temperature. However, if using radiators, on a heat pump circuit, these will require re-sizing to comply with the lower temperatures of the pump. The radiators will require a correction factor of 2.5 to be calculated which increases their sizes by approximately 30%
Use a dedicated power supply with a correctly sized circuit breaker. The final power supply connection must be made from a weatherproof lockable isolator located outside the building. The cable should be either armoured or run in a flexible conduit between the isolator and heat pump.
Unit Power Supply Cable (mm²) Breaker Type and Capacity
HPID6R32 4.0 - 2.5 16Amp Class C
HPID10R32 4.0 - 2.5 20Amp Class C
HPID13R32 6.0 - 4.0 32Amp Class C
HPID17R32 6.0 - 4.0 32Amp Class C
Should the installer wish to extend the control cable from controller to unit, then they can use standard CAT 5 cable.
The defrost operation is based on the combined temperatures detected by three sensors within the heat pump. These are the outside air temperature sensor, the flow temperature sensor and the defrost temperature sensor. When all of these combined detect a need for the unit to run through a defrost cycle the heat pump will stop its current operation. The heat pump will then reverse its operation and direct hot refrigerant vapour back into the ice covered evaporator causing the ice to melt. Once the control system is satisfied this has been achieved, the heat pump will again return to operate the heat pump based on the demand that is being applied, either heating or domestic hot water.
Grant's underfloor heating systems include, Uflex and Uflex MINI. With a drying time of thirty days, the Uflex underfloor system is best suited to the new build and renovation market, this is so the underfloor system can be fitted as part of the floor construction process. Uflex MINI however has a drying time of 3 days. It is suitable for both new builds, as well as retrofits and renovations, when an underfloor heating system is to be fitted in a property with a floor construction already in place. At just 15mm in height, this underfloor system can be installed incredibly quickly and with minimal disruption to a property’s existing floor and door arrangements.
No! The Uflex MINI system is specifically designed to suit retrofits and renovations, when an underfloor heating system is to be fitted in a property with a floor construction already in place. At just 15mm in height, this underfloor system can be installed incredibly quickly and with minimal disruption to a property’s existing floor and door arrangements.
The Microgeneration Certification Scheme is a government driven scheme to promote renewable technologies. It is an internationally recognised quality assurance scheme which demonstrates the quality and reliability of Approved Products by satisfying rigorous and tested standards. MCS is linked to the Governments’s finance schemes and incentives, such as the Feed-in Tariffs (FIT) and the Renewable Heat Incentive (RHI). If you wish to take advantage of these schemes, an MCS approved product must be used. For further information visit https://mcscertified.com/
Grant UK fully understand that some customers may have to self-isolate for a considerable period of time and as such, will not be able to have their Grant product serviced. We are therefore issuing the following guidance.
While it remains important for all appliances, cylinders, stores, tanks, fuel lines and ancillary components to be serviced annually, Grant UK will continue to honour all warranties (on both Standard and Extended) beyond the normal service date up to the 30th September 2020 whether the appliance is serviced or not. This extension relates to Grant oil boilers, Grant Biomass boilers, Grant Aerona Heat Pumps and Grant Cylinders/Thermal stores.
This date may change in line with the recommendations of the UK Government and current information can be found on our website here.
It is imperative that the appliance and connected components are serviced as quickly as possible after this date to ensure trouble free operation.
Grant UK distributes through a network of independent and national plumbing and heating merchants. Please use our Merchant Search tool to locate a distributor near you.
Net zero carbon refers to achieving a balance which ensures that the level of carbon dioxide within the atmosphere is not added to or increased. The Government has set the country a target of achieving net zero greenhouse gas emissions by 2050 which will mean that society, its behaviours and everything it produces, will need to collectively not increase the overall level of emissions, including carbon. Wherever possible, no carbon emissions should be produced but when they are, society needs to counteract these emissions with an environmentally friendly solution to absorb any excess carbon from the atmosphere.
We consider and respond to all complaints and issues, no matter how they are raised or what they refer to. We take every opportunity to resolve complaints at the first point of contact where possible. To make a complaint, please use the contact forms on this site, or alternatively email: info@grantuk.com
Grant UK’s Find an Engineer search facility allows homeowners to find local installers and engineers in their area. Simply click on ‘Find an Engineer’ under the ‘Support’ header and then enter your postcode. The search will then bring up a selection of G1 installers and service engineers based locally to you. You can also filter your search to suit your requirements.