Retrofit or Upgrade a Water Heater in a Caravan Holiday home

Retrofit or Upgrade a Water Heater in a Caravan Holiday home

Many customers wish to replace an existing water heater in their caravan with a new one. The possible options are as follows:

  1. Replace a Morco water heater with the same Morco model
  2. Replace an obsolete Morco water heater with a similar specification current model
  3. Upgrade a Morco water heater to a higher specification current model
  4. Replace another brand of water heater with a current Morco model
  5. Upgrade any water heater to a combination boiler

1. Replace a Morco water heater with the same Morco model

To replace the water heater with a current model does not necessarily require the purchase of a new flue or fitting kit, although it is good practice to replace the fitting kit. If the installer is concerned about the condition or serviceability of the flue or fittings then they should be replaced.

2. Replace an obsolete Morco water heater with a similar specification current model

A new fitting kit will be required in all instances when replacing an obsolete model. Below is a list of obsolete appliances with the current replacement models and the corresponding fluing options:

Obsolete Water Heater Equivalent Replacement Water Heater Flue Type Replacement Flue Option1 Replacement Flue Option 2 Replacement Flue Option3
D51B EUP6 Open FTM038 FTFT250 + FTFP600 FTFT250 + FTPWDS420
D61B EUP6 Open FTM038 FTFT250 + FTFP600 FTFT250 + FTPWDS420
D61E EUP6 Open FTM038 FTFT250 + FTFP600 FTFT250 + FTPWDS420
MP6 EUP6 Open FTM038 FTFT250 + FTFP600 FTFT250 + FTPWDS420
MP11 EUP11 Open FTFTPG101 FTM055 – High Level Vent n/a
G101 EUP11 Open FTFTPG101 FTM055 – High Level Vent n/a
G111E EUP11 Open FTFTPG101 FTM055 – High Level Vent n/a
G11E EUP11 Open FTFTPG101 FTM055 – High Level Vent n/a
F11E EUP11RS or EUP11RSVERT Fan/Room Sealed RSF503 – Horizontal Flue RSF045 – Vertical Flue n/a
F11EL EUP11RS or EUP11RSVERT Fan/Room Sealed RSF503 – Horizontal Flue RSF045 – Vertical Flue n/a


The only material differences between the installation of obsolete and current models are:

  • the smaller flue diameter used on some D51 installations - if your current installation has an 83mm diameter flue you will need to replace it at the same time that you replace the heater with a 90mm diameter flue
  • the change in flue from either the F11E or the F11EL to an EUP11RS with a horizontal flue – an RSF503 will be required for all installations

All open flued water heaters MUST have an overall flue length of at least 600mmm and at least 250mm of this must be external to the caravan on the roof. The flues detailed below fulfil these criteria.

FTM038

This flue provides the external flue terminal and internal flue pipe in one kit. The flue pipe slides inside the flue terminal allowing the water heater to be located between 100mm and 500mm from the ceiling. The 600mm length of the external pipe ensures that the water heater installation conforms to regulations regardless of the length of the internal flue pipe.


FTFT250

This terminal is 250mm high and therefore conforms to the regulations. It MUST be used with an internal flue pipe of at least 350mm length. Both the FTFTP600 and FTPWDS420 can be used for this purpose. These internal flue pipes are 600mm and 420mm in length respectively. The only difference between the two internal flue pipes is that the FTPWDS420 is twin skinned, the outer skin is painted white for decorative effect and it avoids anyone inadvertently touching the hot inner flue pipe during use.

3. Upgrade a Morco water heater to a higher specification current Morco model.

There are 2 basic designs of water heater:

  1. Open flued
  2. Room sealed/fan flued

The room sealed appliances provide advantages outlined later in this section.

There are 3 reasons for an upgrade as highlighted in the table below:

Existing Open Flue Model Replacement Water Heater Reason for Upgrade
D51B, D61B, D61E, MP6 or EUP6 EUP11 More Hot Water
G101, G111E, G11E, MP11 or EUP11 EUP11RS or EUP11RSVERT Room Sealed
D51B, D61B, D61E, MP6 or EUP6 EUP11RS or EUP11RSVERT More Hot Water and Room Sealed


If you plan to change from a smaller open flued model to an EUP11 in order to enjoy a better hot water delivery then the following issues need to be taken into account:

  • The EUP11 can only be fitted in a dedicated boiler cupboard with a full-length door separated from any sleeping accommodation by two full length doors. Some smaller heaters may be installed in kitchen cupboards so direct replacement with a EUP11 is not allowable
  • The EUP11 is more powerful than the smaller models and will require the gas pipe, gas cylinder and gas regulator to be sufficiently large as to cope with the extra power required. Your Gas Safe engineer will be able to advise you but generally the specification should be as below:
    • Gas pipe - 22mm copper from the end of the bottle rubber hose to within 3m of the water heater and 15mm copper for the remaining 3m.
    • Gas cylinder - at least 19kg propane. If other gas appliances use the bottle, then a 47kg bottle should be used
    • Regulator - a 3.5kg per hour regulator is recommended
  • The EUP11 will require a new flue and a new fitting kit as they are of a different size to the smaller water heaters
  • The EUP11 will require additional ventilation in the boiler cupboard - this is because it requires more air to burn to create the extra volume of hot water. This ventilation can either be achieved by doubling the size of the existing floor and wall vents in the cupboard or doubling the surface area of the floor vents AND fitting a flue with integrated high-level ventilation such as the FTM055 (see photo below). Details of ventilation requirements are in the product manual
  • As the EUP11 is an open flued water heater with no fan, it requires the use of a vertical flue

     

FTM055

The top part of the left-hand item is the external terminal and is the regulation 250mm high. The bottom half provides the regulation 350mm between the heater and the ceiling. The roof plate, as pictured on the right, will also need to be fitted and sealed. Once installed it allows air to flow into the boiler cupboard via the outer pipe. Flue gases then exit via the inner pipe and terminal.

If you plan to change from any open flued model to an EUP11RS or EUP11RSVERT in order to enjoy a better hot water delivery and/or the benefits of a room sealed water heater then the following issues need to be taken into account:

  • The EUP11RS/EUP11RSVERT is more powerful than the smaller models and will require the gas pipe, gas cylinder and gas regulator to be sufficiently large to cope with the extra power. Your Gas Safe engineer will be able to advise you but generally the specification should be as below:
    • Gas pipe - 22mm copper from the end of the bottle rubber hose to within 3m of the water heater and 15mm copper for the remaining 3m
    • Gas cylinder - at least 19kg propane. If other gas appliances use the bottle, then a 47kg bottle should be used
    • Regulator - a 3.5kg per hour regulator is recommended
  • The EUP11RS/EUP11RSVERT will require a new flue and a new fitting kit as they are of a different size and type to the open flued heaters
  • The EUP11RS/EUP11RSVERT requires a 240V mains electricity supply so a 3-pin socket will need to be placed near to the boiler
  • The EUP11RS/EUP11RSVERT require an earth for flame recognition. If fitting off grid you will need to consult an electrician
  • The EUP11RS/EUP11RSVERT has no pilot light as it has electronic ignition
  • Fan flued appliances can use a vertical or horizontal flue – in this case the EUP11RS for horizontal flues and the EUP11RSVERT for vertical flues. As all open flued water heaters are vertically flued then the use of a horizontal flue will require the existing roof hole to be made water tight. To install a horizontal flue, it is best for the water heater to be mounted on or close to an external wall. The standard horizontal flue is 600mm long (RSF503) and we also supply an aluminium external flue collar for use with a horizontal flue (RSF060) – see photos below. The vertical flue is 600mm long (RSF045) and can be fitted with roof plates – see details and photos below. 1000mm extensions (RSF041) are available for use with either. If you need extensions, please call Morco for advice.
  • The white portion of the horizontal flue can be cut down to a minimum length of 235mm to ensure the flue projects from the external wall a suitable distance.

EUP11RS Room Sealed/Fan Flued Water Heater Flue Kits

RSF503 Horizontal Flue Kit RSF060 External Flue Collar


If you wish to use a vertical flue and hence utilise the existing hole in the roof then the existing flue components will need to be removed and replaced with a roof plate. We supply a 14 degree roof plate (RSF050, see photo below) or a 5 degree roof plate for use with older bow string caravan roofs (RSF051, see photo below). The roof plate fits to the outside of the roof and to maintain water tightness we suggest a good deal of sealant and some screws are used. The vertical flue is dropped in from the outside and the bottom of the black tube MUST reach the flange on the roof plate. The long white section of the vertical flue can be cut down to within 100mm of the black tube to ensure the flue mates with the flue adapter correctly. The black tube CANNOT be cut down. If the boiler is being fitted where a flue extension is required then use an RSF041 1000mm extension and cut it to fit accordingly.

RSF045 Vertical Flue RSF050 14-degree Roof Plate RSF051 5-degree Roof Plate

4. Replace another brand of water heater with a current Morco model

There are many similarities between brands of water heaters that make the replacement of one with another much simpler than it may seem.

All instantaneous gas water heaters require the following connections:

  • LPG gas supply
  • Cold water supply
  • Hot water outlet
  • Mains electricity - only for fan flued/room sealed heaters such as the EUP11RS/EUP11RSVERT

The majority of water heaters found in caravan holiday homes are open flued and hence have vertical flues.

If the existing water heater flue complies with the following you do not need to purchase a new flue:

  • For the EUP6 models a 90mm diameter vertical flue is required
  • For the EUP11 a 110mm vertical flue is required
  • For both the EUP6 and EUP11 the flue must be at least 600mm in total length with at least 250mm external to the caravan on the roof
  • The flue terminal must be a louvered terminal as in the earlier photos. If it is a mushroom type terminal it must be replaced
  • For the EUP11RS or EUP11RSVERT model you will need to replace any existing vertical or horizontal flue

If the vertical flue diameters are different to the 90 or 110mm standard then you will need to purchase a new Morco flue that corresponds to Morco water heater (see the earlier table on flue compatibility).

New fitting kits will be required in order to replace water heaters from other manufacturers.

A Gas Safe engineer will find the installation straightforward for both types of water heater.

Fitting Kits

Morco supply a number of fitting kits for their water heaters and the table below should be used to determine the correct kit:

Fitting Kit Code Models Gas Pipe Diameter
EUPFK
EUP6 and EUP11 15mm
EUPFK10
EUP6 10mm
PKE
EUP11RS and EUP11RSVERT 15mm


5. Upgrade any water heater to a combination boiler

It is possible to replace any water heater with a combination boiler in order to provide central heating in addition to instantaneous hot water. This is a simpler operation than it may seem but will still need to be carried out by a Gas Safe engineer. Morco offer a central heating kit design service. If you provide us with the following information, we will provide a quote for a kit that has all the components necessary for a full system:

  • The number and size of the radiators or towel rails required
  • The type of flue - horizontal or vertical
  • The position of the boiler in the holiday home (this may determine if a flue extension is needed).

The kit will include all pipes, pipe fittings, pipe insulation, radiators, towel rails, TRV radiator valves, combination boiler and flue. Please  click here for more information.

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