Sector: Hotel
Building: Hotel plant room refurbishment
Products: Wessex ModuMax mk3 boiler, Chesil pressurisation unit, Clenston air and dirt separator
Application: Space heating 1,176kW, DHW

The hotel’s old boiler plant consisted of six Hamworthy Wessex County modules from the 90s with a total output of 1,200kW. Familiar with the brand, the owner got in touch with Hamworthy for a complimentary site survey to identify a suitable replacement.

Space restrictions in the hotel plant room, especially in terms of access, required compact new equipment. Three Wessex ModuMax mk3 196/392V modular boilers, consisting of six boiler modules in three vertical stacks with a total output of 1,176kW, were chosen. At the core of the boiler sits a stainless steel heat exchanger backed by a 10-year warranty. It delivers a high output from a small floor footprint and fits through a standard doorway.

However, space was in fact so limited, there was no room for a temporary boiler plant to provide heating and hot water during the changeover phase between old and new equipment.



Co-operation of experts in their field

Tony Moore, Hamworthy’s area sales manager who carried out the site survey, realised the difficulties of the project and decided to bring more experts on board: Trusted contractor JCS, a team of Hamworthy-approved engineers with decades of experience in installing and servicing the manufacturer’s boilers, as well as flue experts Midtherm Engineering. A long working relationship with Hamworthy and familiarity with its products allowed both businesses to develop a strategy for the plant upgrade.

Jason Collyer, director and lead technician for JCS, added,

“Access was limited and although the Wessex ModuMax mk3 boilers fit through a standard door, access to the plant room was further restricted by existing installation pipework. There was also little room for storage on-site whilst the works took place. The boilers were delivered to our stores, dismantled and transported to site when required, and then rebuilt within the plant room – a service we offer via Hamworthy if needed. We like using the Wessex ModuMax modular boilers as they are a reliable range and simple to service.”

As part of the system upgrade, the flue needed updating to deal with pressure and condensate generated by the new boilers. Ian Ford from Midtherm Engineering designed a temporary flue with the help of JCS; this allowed one stack of the new boilers to be run as a temporary plant to ensure uninterrupted heating and hot water during the transition.

Ian elaborated,

“Because of the location of the boiler room in the basement, maintaining the heating and hot water service was not straightforward. Working alongside Hamworthy and JCS, we formulated a game plan which resulted in a phased changeover of the flue, boilers, upgraded ventilation system and lining of the existing flue system to suit the new Wessex ModuMax condensing boilers. Initial work involved running a temporary flue from the boiler room, through some existing ductwork into the lightwell, discharging above roof level.”

The old Wessex County boilers were removed in stages. Furthermore, existing mechanical ventilation was inadequate, and an additional high-level duct was required. The latter served as temporary flue route for the first stage of the boiler replacement to facilitate the remainder of the works.


Boiler replacement step by step

First, the boilers were delivered to JCS’ workshop where they were dismantled. Pipework was prefabricated and along with the Wessex ModuMax mk3 prepared for transport to the hotel.

Once on-site, two Wessex County modules were isolated, drained, dismantled and removed from the site. This allowed JCS to deliver and assemble the new boilers which were then connected to water and gas side pipework, including two boiler shunt pumps, back to the existing boiler isolation valves in readiness for connection to the temporary flue and wiring which was carried out by other parties. This was followed up by a check for correct operation.

Jason Collyer, commented,

“In phase one, we installed the first Wessex ModuMax stack of two vertical modules which would provide temporary heating until the entire system was in place. In phase two, we removed the four remaining old boiler modules to deliver and assemble another two stacks of the Wessex ModuMax mk3 boilers on-site to replace them.”

Again, installation of boiler shunt pumps and wiring followed, along with the usual checks.

He continued,

“For the boilers, we used Hamworthy’s matched pipework kits. Each [three in total, one per boiler stack] was connected to the existing system pipework, incorporating a shunt pump on each. This also allowed for removal of the existing, poorly sited boiler primary circuit pump.”

About the process of upgrading the flue, Ian Ford added,

 “JCS installed one stack of the Wessex ModuMax mk3 boilers first and connected it to the temporary flue we designed. New high-level ductwork was then installed to help regulate the temperature in the boiler room. 

The existing flue header was removed, scaffolding erected to give access to the top of the chimney, and a CCTV survey of the existing flue riser carried out. Due to poor access, the latter would not be simple to remove, and there was an offset below roof level. We were able to install our Furanflex composite liner inside the existing flue riser which made the current system suitable for use with the new, much more efficient condensing boilers. A new flue header was then installed, connected back to the boilers and the installation pressure tested. The temporary flue was adapted to be used as an additional high-level ventilation duct, and the job was done, all carried out within the space of a few weeks with no downtime for the hotel. It was a pleasure to work on this project, especially as it is one of London’s sought- after residences.”


Ensuring the protection of the new equipment

The installation was completed with the addition of a Chesil pressurisation unit to provide adequate system pressure for the new boilers in a closed heating system and a Clenston air/dirt separator to keep the system clean.

Jason explained,

“Although the system was flushed and treated, we were aware that historically the system water quality had been poor. We decided to fit the air/dirt separator to ensure the new boiler plant was adequately protected and stressed the necessity for regular system water quality checks. Additionally, we installed two plate heat exchangers and buffer vessels to satisfy the hotel’s increasing hot water demands.” 

Lastly, to ensure the condensate will not be causing corrosion, the flue condensate pipework was run to the nearest drain.

Upon completion of the installation, the entire system was commissioned by JCS. If this is carried out by Hamworthy or one of its service partners such as JCS, it does not only ensure the products are set up to manufacturer standards but also improves the warranty terms.

Successful completion without interruption

About the co-operation with Hamworthy and the job, Jason concluded,

“Hamworthy were involved throughout each stage of the project and very much a part of the team when it came to working out the solutions and meeting the timings required for the installation.
From the initial survey to flexibility with deliveries and product support throughout our works, I really can't think of another product or company which could have helped complete this project so successfully. Then of course co-operation with Midtherm made our life easier, too. Everyone is familiar with the products and we can rely on years of experience in terms of flue design.

Lastly and most importantly, carrying out this job for a prestigious hotel such as the Baglioni, we were well aware of our responsibility and are pleased that the project was completed without interruption. While we were regularly called out for poor hot water and breakdowns before the upgrade, we have had no call outs since the installation of the new boilers. We’re looking forward to our next service visit which will be much quicker and easier with the new plant fitted."

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