The Telford Tempest 300L Indirect Heat Pump Cylinder is designed to store domestic hot water in systems using an air- or ground-source heat pump as the primary heat source. Its purpose-designed 3m² coil supports heat transfer from a compatible heat pump, and a factory-fitted 3kW immersion heater provides backup heating. The cylinder is made from duplex stainless steel and is supplied with an unvented kit and external expansion vessel.
The manufacturer’s product information lists a 300-litre capacity, 1780mm height and 580mm diameter. It gives the empty weight as 44kg and the standing heat loss as 2.22kWh per 24 hours, equivalent to 92W. Check the cylinder dimensions, access route, connections and system compatibility with a suitably qualified installer before purchase.
300L Capacity
Heat Pump Compatible
Duplex Stainless Steel
3m² Heat-Exchange Coil
At a Glance
Cylinder Type
Indirect Unvented
Tempest heat pump range
Capacity
300 litres
Model code: TSMI300/HP, as listed
Dimensions
1780 × 580mm
Height × diameter
Backup Immersion
3kW
Factory-fitted, as specified
Key Features
300-Litre Hot Water Storage
Offers a substantial stored-water capacity for larger households and other suitable installations. Have the required capacity assessed against the property’s hot-water demand.
Designed for Heat Pump Systems
The Tempest Heat Pump Indirect cylinder is designed for use with an air- or ground-source heat pump as the main heat source.
Purpose-Designed 3m² Coil
The 3m² heat-exchange coil is designed to transfer heat from a compatible renewable heating system into the stored water.
Duplex Stainless-Steel Construction
The cylinder is manufactured from duplex stainless steel. The manufacturer also specifies 316L stainless-steel coils and 22mm compression fittings.
Factory-Fitted Immersion Heater
A factory-fitted 3kW immersion heater provides backup heat. Confirm the electrical supply and installation requirements with your installer.
Unvented Kit and Expansion Vessel
The manufacturer lists an unvented kit and a remote expansion vessel with a mounting bracket among the supplied components.
Important Installation Guidance:
This is an unvented hot-water cylinder. A suitably qualified installer should confirm system compatibility, available space, access route, operating pressures, safety components and connections. Installation and commissioning must follow the manufacturer’s instructions and applicable regulations.
Key Specifications
| Product |
Telford Tempest Heat Pump Indirect Unvented Cylinder |
| Model Number |
TSMI300/HP, as listed by a retailer |
| Range |
Tempest Heat Pump |
| Capacity |
300 litres |
| Height |
1780mm |
| Diameter |
580mm |
| Empty Weight |
44kg |
| Full Weight |
338kg |
| Cylinder Material |
Duplex stainless steel |
| Heating Type |
Indirect |
| Coil Surface Area |
3m² |
| Immersion Heater |
Factory-fitted 3kW |
| Standing Heat Loss |
2.22kWh/24h (92W) |
| Maximum Supply Pressure |
12 bar |
| Maximum Operating Pressure |
3 bar |
| T&P Relief Valve Setting |
7 bar / 90°C |
| ERP Rating |
C |
| Expansion Vessel |
Remote vessel with mounting bracket, listed as supplied |
Frequently Asked Questions
Is this cylinder suitable for a heat pump?
Yes. The Tempest Heat Pump Indirect range is designed for use with an air- or ground-source heat pump as the main heat source. Confirm compatibility with your specific system and installer.
What is the coil surface area?
The 300-litre model is listed with a 3m² coil surface area.
What is included with the cylinder?
The manufacturer lists an unvented kit, external expansion vessel and factory-fitted 3kW immersion heater among the supplied items. Confirm the full package contents with the seller before ordering.
At GetPlumb, we strive to provide reliable and cost-effective delivery options to our customers. Please review our shipping policy below.
🆓 Free Local Delivery (Orders £100 & above)
We offer FREE delivery on orders £100 or more
for selected local areas.
Eligible Postcodes Include:
- RG*
- SL*
- OX10*, OX11*, OX49*
- HP1*, HP3*, HP8*, HP9*, HP10*, HP11*, HP12*, HP13*, HP14*
- WD*, HA*, UB*, TW*, KT*
- W1* – W9*
- NW*, SW*
Delivery Time: 2–4 working days
Shipping Cost: £0.00
📦 Standard Shipping (Weight-Based Rates)
For orders that do not qualify for free delivery, standard
shipping rates apply based on total cart weight.
- For cart weight between 0–2 kg, the shipping cost is £4.50 with a delivery time of 2–4 working days.
- For cart weight between 2–24 kg, the shipping cost is £9.99 with a delivery time of 2–4 working days.
- For cart weight between 24 kg and above, the shipping cost is £60 with a delivery time of 2–4 working days.
🧱 Block Salt (Harvey’s) – Unit-Based Shipping
This rate applies only to Harvey’s block salt products.
- £7.99 is charged for every 3 items.
- The charge increases by £7.99 for each additional set of 3 items.
Examples:
- 1–3 items → £7.99
- 4–6 items → £15.98
- 7–9 items → £23.97
Delivery Time: 2–4 working days
📏 Large / Long Items (Length-Based Shipping)
For oversized items where the product length is 1.5 metres or more:
Conditions:
- Product length ≥ 1.5 m
- Cart weight ≤ 40 kg
Shipping Cost: £18.00 (flat rate)
Delivery Time: 2–4 working days
Collection from Store
Customers can also choose to collect their order from our store in
Reading, UK, at no additional charge. For any questions regarding shipping, please contact our support team at online@getplumb.co.uk.
