RM Prostel Indirect Unvented Hot Water Cylinder - 300L


inc VAT

In Stock1 - 2 Working Days Delivery / Collection
The RM Prostel indirect hot water cylinders have been carefully constructed using high quality components and are design with performance in mind.
RM Cylinders

RM Prostel S300PI Details

The fully WRAS approved RM Prostel hot water cylinders are some of the slimmest cylinders on the market and are constructed from Duplex stainless steel. A competent and reliable companion for any standard boiler this indirect cylinder contains a high efficiency, quick recovery coil that can make it the perfect choice for even the busiest of homes. The Prostel can ensure longlasting hot water stores in a unit that is built to last.

The technical benefits of the Prostel cylinders

  • Working pressures – Min: 1bar, Max: 3bar
  • 22mm compression connections throughout
  • Minimum water supply 1.5bar, 20 Litres/min
  • Primary coil circuit must be fully pumped
  • 50mm insulation
  • Flat base for stability
  • Immersion heater – 3kW incoloy
  • Immersion reheat time (mins): 285
  • Clearly labeled unit connections
  • Superior insulation valves with an ODP of 0 and GWP of 1
  • Butt welding for long life
  • Pickled to ensure longer life
  • 25 year guarantee on the vessel, 2 years on parts
  • Weight when full: 347(kg)

Control Settings

  • Pressure reducing valve set at 3bar
  • Expansion relief valve set at 6 bar
  • Temperature and pressure relief valve at 7 bar and 90°C
  • High limit stat set at 85°C
Please note RM cylinders are made to measure and cancellations/returns are subject to up to a 35% administration fee
More Information
ManufacturerRM Cylinders
Product TypeIndirect
Valves IncludedNo
Cylinder SystemUnvented


Most Mainland UK Postcodes

All RM Cylinders hot water cylinders are delivered directly from the manufacturer to you.

Product Type / ValueServicePrice (Inc VAT)
Copper Cylinders Economy Courier Delivery (3 - 5 Days) Free
Standard Courier Delivery (2 -3 Days) £6.95
Next Working Day if ordered by 12.00 PM £12.00
Stainless Steel Unvented Cylinders up to 300 Litres Economy Courier Delivery (3 - 5 Days) Free
Standard Courier Delivery (2 -3 Days) £6.95
Next Working Day if ordered by 12:00 PM £12.00
Stainless Steel Vented (Aquastel Range) Economy Courier Delivery (3 - 5 Days) Free
Standard Courier Delivery (2 -3 Days) £6.95
Next Working Day £12.00
Made To Order Cylinders 7 - 10 Working Days £6.95
All items in this category Next Working Day and Saturday Deliveries Call to check
All items in this category Collection from Maidenhead - usually 1-3 working days
We will contact you when your order is ready
Free of charge

For collections please do not travel until you have had confirmation your order is ready.

If you need items urgently, please call ahead to check lead times. Our Sales Team are available on 01628 760 440 Monday to Friday 8.00am to 5.00pm.

We do not recommend Tradesmen are booked until items are safely received and checked.



RM Cylinders

RM Cylinders are delivered directly from the manufacturer. Delivery charges are calculated at the checkout. Standard delivery to England, Wales and parts of Scotland starts from only £6.95 for RM Cylinders Hot Water Cylinders although exceptions do apply and are listed below.

Please note:

Deliveries are generally only made on working days. Working day refers to Monday to Friday and excludes weekends and Bank Holidays. The delivery options on this page relate to this product only and may not be available if other items are added to your basket. Only one delivery charge is made per order and the highest will normally take precedence.

Returning an item

We offer a no quibble 14 day returns policy on all goods supplied, subject to a few minor exceptions. Find out more on our Returns Policy page.


Highlands & Islands of Scotland (and postcode exceptions)

ItemsServicePrice (Inc VAT)
Hot Water Cylinders Direct From Manufacturer £36.00

Includes the following postcodes:
AB36-AB38, AB55-AB56, FK17-FK21, HS, IV1-56, IV70, IV63, KA27, KA28, KW1-KW17, PA20-PA45, PA47-PA49, PA60-PA78, PH19-PH26, PH30-PH44, PH49-PH50, TR21-TR25, ZE


Northern Ireland Services (BT Postcodes)Price (Inc VAT)
Direct From Manufacturer - Usually 3 - 5 working days £54.00
Express Delivery and Saturday Delivery Not Available
Ireland (Eire) ServicesPrice (No VAT)
Direct From Manufacturer - Usually 3 - 5 working days £50.00
Express Delivery and Saturday Delivery Not Available

Channel Islands & Isle of Man

JE, GY, IM Postcode ServicesPrice (No VAT)
Direct From Manufacturer - Usually 4 - 6 working days £18.00
Express Delivery and Saturday Delivery Not Available


All delivery times and dates especially next working day and weekend delivery times are always provided as a guide and are not 'guaranteed'. We use reliable couriers with a 99.9% success rate however once a consignment is within the courier network there is always a very small chance something could go wrong, however unforeseen. Trading Depot will not be liable for any costs incurred by any such delays waiting for goods. Trading Depot advises strongly against booking Tradesmen until after goods are safely received and checked for this exact reason.

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