Wet underfloor heating review
All underfloor heating insulation requirements must comply to the latest building regulations. Normal screed can be used for underfloor heating systems. No further additives are required. Anhydride screed can be 50 mm only. It is very important to use a vapour barrier when using liquid screed for wet underfloor heating.
The best floor finish for underfloor heating water systems are tiles or a stone floor as these floor finishes have very low thermal resistance. Use flexible fixing adhesive to avoid cracks.
Any type of boiler can be used for underfloor heating. Mixing valves must be used to lower the temperature for the underfloor heating system.
Electric boilers can also be used with water underfloor heating.
For a domestic building the hot water demand is normally about 3 kW.
Underfloor heating water is best operated 24/7 every day of the heating season. Night set-back is normally used to lower the temperature of the underfloor heating system during the night. Maximum drop for night set back should not be higher than 6 degree C.
Our underfloor heating system can be fixed if there is a leak. The underfloor heating pipework for the loop that has been damaged needs to be isolated and the floor surface exposed. By using our underfloor heating coupler the leak can be fixed.
Our underfloor heating warranty is as below;
This certificate hereby guarantees the underfloor heating pipe against manufacturing defect, including consequential damage, for a period of 10 years from date of installation as per the manufacturer’s policy with AXA Belgium Insurance Co Ltd. The underfloor heating pipe is further guaranteed against manufacturing defect for a further 40 years on a supply only basis. Manifolds, etc are guaranteed for two years by the manufacturer, and electricals etc are guaranteed by the manufacturer for two years following the date of production. Further details can be found on the respective manufacturers’ web sites.
Water Underfloor Heating Information
Our water underfloor heating systems can be added to a Conservatory, extension or a new build. Many house builders in the UK prefer to install underfloor heating water systems instead of radiator systems. The self build market is also very popular for fitting underfloor heating water systems.
Underfloor heating is really the preferred choice to be used with renewable energy sources, such as heat pumps.
Wet underfloor heating in a screeded/concrete floor is normally the optimum heating system for underfloor heating. The underfloor heating pipework is normally fitted 100 mm from the wall and the pipes centres is normally c/c 200 mm.
If the aluminium plates are used for a timber suspended floor solution with underfloor heating, then it is recommended to use 100 mm mineral wool insulation below the plates.
Underfloor heating systems are now very common is sports halls, car show rooms, hospitals and supermarkets as the heat is at floor level, which makes for the best heating systems available.
At Underfloor Heating Systems Limited we have over 30 years of underfloor heating experience. We can design your underfloor heating system to suit your requirements. Our technical department is here to help with any questions regarding insulation, controls, temperatures, pressures, etc.
Our underfloor heating manifolds are supplied with red and blue ball valves.
Programmable Digital Room Thermostat for Underfloor Heating
We can also offer a surface mounted programmable room thermostat for our underfloor heating water systems. The Danfoss TP5000 Si room thermostat.
The Danfoss TP5000 Si is a 2 core + earth room thermostat. Battery operated. The room thermostat allows you to programme different temperatures at different time periods. You can programme one set of times and temperatures for week days with a different set of temperatures for weekend days, this is referred to as 5/2 day operation.
The thermostat can also be set up by your underfloor heating installer to provide one set of times and temperatures that are repeated each day of the week. This is referred to as 24 hour operation.
All underfloor heating thermostats can be set to provide up to 2, 4 or 6 time and temperature settings each day.
Our wet underfloor heating TP5000 Si room thermostat comes with overrides, including a programmable frost setting.
The underfloor heating room thermostat comes ready programmed with a set of operating times and temperatures which suit most people. Please remember that some of the options available will depend on how the underfloor heating water installer has to set up the unit.
Underfloor Heating Wiring Centre Heatmiser UH3
The Heatmiser underfloor heating wiring centre is one of the best on the market in the UK. It comes with a 5 Amp fuse time delay.
Mains supply will connect from a fused spur into the underfloor heating wiring centre. There is also a relay for switching the boiler/two port valve on. The wet underfloor heating wiring centres comes with connections for the underfloor heating pump.
A two port valve can be connected to the UFH valve connection. Some valves use different colours. If the end switch is not being used put a link between Gr and Or.
The underfloor heating water wiring centre can be fitted with eight room thermostats. Each room thermostat can control up to four underfloor heating loops, ie four actuators.
A time clock can also be fitted to the underfloor heating wiring centre. Zone 8 on the wiring centre can be isolated, so this connection could be used for the radiator system on the First Floor.
Underfloor Heating Programmable Room Thermostat
We use Heatmiser PRT programmable room thermostats for our water underfloor heating systems.
A programmable room thermostat is both a programmer and a room thermostat. A room thermostat will require free flow of air to sense the temperature, so they must not be covered by curtains or furniture.
For our water underfloor heating systems we recommend that the room thermostat is fitted at eye level. Do not install the underfloor heating room thermostat near a direct heat source. The thermostat is designed to be flush mounted with the use of a back box of 35 mm.
The fire symbol will show that the room thermostat is asking for heat. If a frost icon is shown then the underfloor heating is off and the room thermostat is protecting the building against frost.
The Heatmiser PRT room thermostat can also be locked.
The Heatmiser PRT is supplied with comfort levels, the default times are;
08:00 – 21 degree C
09.30 – 16 degree C
16.30 – 22 degree C
23.00 – 17 degree C
To turn the underfloor heating off press the start button. You will see the frost icon on the screen, this means that the underfloor heating is off but the building is protected against frost.
To turn the underfloor heating back on press the start button and the frost icon will disappear.
To turn the thermostat off press and hold the start button until the display goes off.
To make a temporary change to the underfloor heating air temperature setting, press arrow down or arrow up. Set the temperarure you want and press A to accept.
To set the comfort levels for the underfloor heating water system for the complete week press the clock button.
H is for holiday setting.
Actuator for Underfloor Heating
Our underfloor heating actuator from Henco in Belgium is made to the highest quality possible. It is an ON/OFF electrical head and the actuator is fitted on the underfloor heating return manifold.
The specification for our underfloor heating Henco actuator is;
Type of load controlled by the extrenal circuit – 700 mA.
Type of action – Modulating.
Pollution grade – 2.
Rated pulse – 4 kV.
Type of movement – Linear movement.
Maximum actuator stroke – 3.5 mm.
Working stroke on valve – 2.5 mm.
Power consumption – 2.5 W.
The actuator is 230 V and normally closed. No power to the underfloor heating actuator means that is is closed. There is a window on the actuator that will show if the actuator is closed or open. Red means closed and black means open.
The underfloor heating actuator is normally controlled by a room thermostat via an underfloor heating wiring centre.
When mounting the actuator on the underfloor heating return manifold, the valve plug shuts off the flow of fluid. When voltage is applied a linear movement of the thermostatic element is caused, the valve plug opens which then allows the fluid to flow.
Before fitting the underfloor heating actuator, remove the protective cap on the underfloor heating manifold. Screw the actuator ring by hand on the threaded part of the underfloor heating manifold and lock it. Connect the wires to the underfloor heating wiring centre.
Please note, never open the actuator body casing even of failure as this could cause injury.
Underfloor Heating Manifolds
Our underfloor heating manifolds are made in Germany by Watts/Dumser to the highest quality possible. The underfloor heating brackets are mounted to adjustable C-rails. The wet underfloor heating manifolds are supplied with a ball valve set and a filling set. The underfloor heating manifolds are each fitted with a 1″ male thread for fixing the ball valves and the filling sets. Use the O-rings provided when fitting the ball valves and the end sets as the O-rings are self sealing. PTFE tape can also be used.
Each underfloor heating circuit can be identified by self adhesive labels.
To fit our Henco underfloor heating pipe to the underfloor heating manifolds, use the 16 x 2 mm Euroconus fittings provided. Cut the multilayer pipe at a right angle and push the nut and the split-ring over the underfloor heating multilayer pipe. Calibrate the pipe and push the insert into the underfloor heating pipe. Connect to the underfloor heating manifold. Screw the nut by hand and afterwards use a spanner to tighten the nut.
To adjust the flow meters on the underfloor heating manifolds remove the plastic cap on the return manifold. By using the air bleed key provided the flow rates can be adjusted for each underfloor heating water loop.
Our actuators will fit on the return underfloor heating manifold after the flow has been adjusted for each wet underfloor heating loop.
Underfloor Heating Water
Always check that the floor construction used can be used for underfloor heating water systems. For a timber suspended floor solutions is it always easier to install the underfloor heating pipework from above. We do not recommend installing any underfloor heating system from below for timber suspended floor as this is very time consuming.
All ground floor insulation requirements must meet the Part L building regulations. When our approved underfloor heating installers arrive on site it is important that mains water supply is available so they can fill the underfloor heating system and perform a pressure test.
If the underfloor heating system is not switching on the boiler, check the wiring. Be aware not to kink the Henco underfloor heating pipe when installing the wet underfloor heating system.
If there is a low flow rate on the underfloor heating manifold, check that the underfloor heating pump is running at full speed, ie setting number 3. Check that there is no air in any of the water underfloor heating loops.
If there is a low water temperature going into our underfloor heating manifolds, check that the boiler is set to maximum setting. The water temperature to the underfloor heating system can be increased by adjusting the thermostatic mixing valve.
Henco Underfloor Heating Pipe
At Underfloor Heating Systems Limited we use Henco mulitlayer pipes for our underfloor heating system. See website www.henco.be.
The wet underfloor heating system must be 100 % oxygen diffusion tight, which is guaranteed by using Henco multilayer pipe. The aluminium layer eliminates any corrosion risk in the underfloor heating system.
The aluminium layer will also give our Henco underfloor heating pipe excellent conductivity, which is a must for underfloor heating pipework as they depend on low temperature water to give out heat. By using a pipe with aluminium layer, we will get more heat output than most normal plastic pipes.
The Henco underfloor heating pipe is very easy to bend and the pipe will stay in shape. There is no spring back effect with Henco multilayer pipe.
Underfloor heating water system are also self regulating. The reason for this is the low floor temperature that can be almost the same as the air temperature.
The Henco pipework is made of PE-Xc/Al/PE-Xc. The pipe is 16 x 2 mm in size. Maximum loop length is 110 m for any loop. The outside diameter is 16 mm and the wall thickness is 2 mm.
The aluminium thickness for our multilayer pipe from Henco is 0.4 mm. Maximum operating temperature is 95 degree C and maximum operating pressure is 10 bar.
The minimum bending radius is 80 mm for our 16 x 2 mm underfloor heating pipe.
The weight is 0.125 kg/m and the water content is 0.113 l/m.
Heat conduction coefficient for the Henco underfloor heating pipe is 0.43 W/mK and the linear expansion coefficient is 0.025 mm/mK.
Heat Pump with Underfloor Heating Water
As the government is trying to reduce the carbon foot print, the demand for heat pumps are growing. There are ground source heat pumps, water source heat pumps and air source heat pumps. A heat pump is basically a fridge in reverse.
Water underfloor heating and heat pumps normally go hand in hand as the heat pump will be able to work at low flow temperatures, but there are a few issues to watch out for. A heat pump will work at is best if the building is very well insulated. It also helps if the floor constructions is concrete floors for all levels of the project.
An air source heat pump will take the heat from the outside air. A water heat pump will take the heat from a lake for example and a ground source heat pump will take the heat from the ground.
A ground source heat pump is the most expensive one as pipework needs to be buried in the ground. The cheapest heat pump to purchase is an air source heat pump, but the efficiency will not be as good as a ground source heat pump.
The COP – Coefficient of Performance of a heat pump will vary with the flow temperature. For example 55 degree C water flow temperature might just give a COP of 3, but 35 degree C water flow temperature will give a COP of 5.
This is why a heat pump will work best in a screeded floor as it might be possible to run the heat pump at 35 degree C. In a timber suspended floor the heat pump might need to run at 55 degree C.
To allow for individual room thermostats it is always recommended to fit the heat pump with a buffer tank. Sometimes there is no need for our underfloor heating mixer packs when using a heat pump.
The heat pump company needs to provide large enough pump for the complete underfloor heating system if no mixer packs are used by the underfloor heating manifolds.
Heat pumps can also be used for underfloor cooling, but these sort of systems are not very popular in the UK at the moment.
