Heating Services & Underfloor Heating Case Study
- Site Location : Cookham Dean, Berkshire
- Application : New Domestic Annex Building
Client Brief
- To have spontaneous hot water on an ad-hoc basis within the new annex building - which would not be continually occupied
- For the gas installer to connect onto and heat the underfloor heating pipework - already laid by the main building contractor
- For the gas installer to specify and install suitable controls for the underfloor heating and boiler
- To locate the boiler in the basement
The Solution
The discreet location of the boiler within the basement is an ideal position but it did bring about its own problems. For technical reasons, combination boilers are not generally fitted in below ground applications, but by drawing on our knowledge and experience, we were able to specify the Baxi Platinum boiler model, which has a special device to overcome this.
In order to connect the combination boiler to the under floor heating system we installed special controls to create two independent zones of heating. One zone serves the open plan basement area and a second zone controls the ground floor areas. The basement open plan area is time and temperature controlled by a single programmable room thermostat, and the ground floor heating is linked to three programmable room thermostats providing independent time and temperature control for each area.
Conclusion
On completion of the installation, a fully functional highly efficient heating and hot water system was operational. Hot water is heated on demand instantaneously, which means no hot water is wasted through storage. The underfloor heating system heats the spaces using water heated to 350C, which compared to 820C for a radiator based system is a 57% reduction in heat requirement.
The high efficiency Baxi boiler operates at 92% combustion efficiency, which means we delivered a very cost efficient, low carbon and effective heating and water system. In addition to this, for long-term peace of mind we were able to provide a five year parts and labour boiler warranty – free of charge.
Central Heating Boiler Replacement Case Study
- Site Location : Marlow, Buckinghamshire
- Application : Replacement Boiler & System Upgrade
Client Brief
- To resolve a long-standing problem on the client’s central heating system. Our Client explained that despite engaging with numerous heating companies over the last ten years, nobody had quite managed to get their heating system to work satisfactorily.
The system had always struggled to function which became particularly noticeable during cold snaps, predominantly affecting the ground floor radiators. Many attempts to solve this problem had been made unsuccessfully over an extended period of time – to great cost and no satisfactory conclusions. The client also said that in addition to the long term problems, he had recently noticed possible signs of water leakage from the ground floor heating pipe work within the concrete ground floor.
Diagnosis
From gaining this information from our client it became clear the system had been poorly operating ever since the current boiler was originally installed. We also learnt that when the current boiler was installed twelve years previously it was relocated to a new position. To the naked eye the system appeared to be installed correctly, but many pipes were concealed so we could not conclude this without further investigation.
Solution
We suggested the following course of action:
- Inspect the current boiler and check its operation and heat output
- Check all existing heating and hot water controls & check their operation
- Remove some panelling and flooring and check the original pipe work installation and correct if necessary
- To disconnect the two ground floor radiators and make the leaking pipework under the floor redundant
- To run new pipework to the living room radiator
Conclusion
We ultimately found that this installation had a fundamental piping error that was installed out twelve years previously. The client also had leakage and damage on their existing boiler and chose to replace it with a new high efficiency Worcester Bosch 18Ri condensing boiler. We also upgraded the controls and installed a new hot water cylinder, and corrected the underlying error in the pipework to provide an extremely efficient and reliable system.
Commercial Boiler Replacement Case Study
- Site Location : Ascot, Berkshire
- Application : School
Client Brief
- To provide new replacement gas fired boilers for a school block, due to the inefficiency of the existing plant compounded by ongoing reliability problems
- To retain the existing hot water system
- To provide a new plant room arrangement that was simple to control, reliable and brought value for money in terms of capital expenditure
The system had always struggled to function which became particularly noticeable during cold snaps, predominantly affecting the ground floor radiators. Many attempts to solve this problem had been made unsuccessfully over an extended period of time – to great cost and no satisfactory conclusions. The client also said that in addition to the long term problems, he had recently noticed possible signs of water leakage from the ground floor heating pipe work within the concrete ground floor.
Survey of Existing Installation
The existing heating system at this school consisted of two 50Kw floor standing conventional flue gas fired boilers, which were approximately 20 years old. The boilers had an efficiency rating of 75% but were in a poor order – resulting in efficiencies far less than this original badge rating. They were controlled by a complex optimising and compensating energy management system.
The boilers served thirty large low-surface temperature (LST) radiators, each with thermostatic radiator valves which provided local temperature control. The pipework arrangement was a sealed system with a very old pressurisation unit to maintain water levels.
Solution
In order to ensure we met the value for money criteria outlined by our client, we initially carried out heat loss calculations for the building. This study enabled us to determine that the original boiler plant was oversized by 20%, which meant we could select newer and smaller boilers that had ample capacity to meet the building load.
The boilers we selected were two Worcester Bosch 40Cdi Greenstar wall mounted high efficiency condensing boilers. Each boiler met two thirds of the building capacity, which is the correct criteria for installing a twin boiler plant installation.
The boilers were installed in a reverse return two pipe arrangement with a common header. The pipework was extended to connect onto the existing unvented hot water plant as stipulated by the client – and the heating pipework had two zone control valves fitted in a parallel arrangement. In order to provide effective but simple controls we installed a Drayton optimising programmable room thermostat and a Danfoss domestic type twin channel programmer.
Conclusion
On completion of this installation we had provided a cost effective, reliable system with low running costs. Gas consumption savings were delivered by installing boilers with a 92% efficiency rating. Improved controls brought about further savings, particularly the optimising programmable room thermostat, which is able to control the building at different temperatures at different times of the day.
In addition to the optimisation feature is a self learning control that is able to determine how long it takes to heat the building, which means the boilers only fire when they really have to. Capital expenditure was significantly reduced by simply calculating the correct boiler plant size and applying simple but effective controls.
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