Heat Siphon Z3.75hpx – 26kw, 3-Phase, Digital Controls

£3,850.00 (£3,208.33 exc VAT)

Availability: 10 in stock


Heat Siphon Swimming Pool Heat Pumps – The Market Leading Pool Heater in the USA

heat siphon swimming pool heat pump

If you are looking for the most powerful heat pumps on the market,
then look no further than the famous Heat Siphon range of pool heat
pumps from HeatPumps4Pools.

Heat Siphon are a worldwide leader in swimming pool heat pumps. They have been made in the USA for over 30-years. HeatPumps4Pools supply and maintain these top quality products to the UK and Europe.

These are the new R410 gas based range of Heat Siphon heat pumps that were launched in April 2010. This gives them enhanced output and operating efficiency.

Our Heat Siphon models are made specifically for the European market and are made differently to USA models.

heat siphon swimming pool heat pump heater installation

All Heat Siphon swimming pool heat pumps supplied by HeatPumps4Pools have the following features:-

  • One of the best performance and heat output of any heat pump – COPs of over 6
  • Titanium heat exchanger to prevent corrosion by the pool chemicals
  • UV Stabilized Flame retardant PVC casing to prevent corrosion
  • Excellent heat output
  • Quiet operation
  • Simple and reliable operation
  • R410a environmentally friendly and super efficient refrigerant gas
  • 50 Hz electrical operation for European power supply
  • Scroll compressor on all models
  • Optional “soft-start” kit

The models can come with either an analogue or digital display.


Digital Controls
Analogue Controls

And can be supplied with either single phase or 3-phase electrical supply models

Excellent Features and Specification

Heat Siphon Features

Quality Copeland Compressors

Heat Siphon Copeland Compressor

Heat Siphon Models

ModelOutput Power (kw)Digital / Analgogue controlsSingle / 3-PhaseCOPCircuit Breaker RequiredVoltage
C2.50hpx15.3kwAnalogue3-Phase6.710A 380
C3.75hpx26.0kwAnalogue3-Phase6.720A 380
C5.75hpx35.4kwAnalogue3-Phase6.1820A  380
C7.00hpx39.5kwAnalogue3-Phase6.520A 380
Z2.50hp5012.8kwDigitalSingle5.0130A 208/230
Z3.75hp5023.4kwDigitalSingle6.2440A 208/230
Z5.75hp5028.7kwDigitalSingle6.250A 208/230
Z2.50hpx15.3kwDigital3-Phase6.710A  380
Z3.75hpx26.0kwDigital3-Phase6.720A  380
Z5.75hpx35.4kwDigital3-Phase6.720A  380
Z7.00hpx39.5kwDigital3-Phase6.5 20A 380

 (COP measured at 80F air, 80F water temp and 80% relative humidity)

What size heat pump do I require for my pool?

For an outdoor pool in the UK that is kept covered, use the following guide:-

1. Work out the surface area of your pool in square feet

2. For pools up to 350sq ft, you will need the 2.50hp model

3. for pools up to 700sq ft you will need the 3.75hp model

4. for pools up to 1000 sq ft, you will need the 5.75hp model

heat siphon swimming pool heat pump heater installation


All Heat Siphon products come with the following warranty:-

  • Lifetime warranty on the titanium heat exchanger
  • 5-Years warranty on the compressor
  • 2-years warranty on all other parts
  • Inside the UK the warranty is parts and labour. Units installed outside the UK have a parts-only warranty.

At HeatPumps4Pools we always carry a full range of spare parts for all Heat Siphon products


All Heat Siphon heat pumps have excellent performance and provide one
of the highest amount of heat per £ than any other unit that we sell

The new R410a gas based units operate with air temperatures down to +6c

Soft-Start Kit

The soft start kit can be added to the order for any Heat Siphon heat pump.

The kit helps to prevent a power “spike” when the heat pump starts.

It smoothly brings the unit up the normal running current.

This can be useful if you have a sensitive fuse/breaker which may otherwise trip out without the soft start kit.



Model Weight
C250HP/Z250HP225 (102)34 (86)39 (99)36 (91)
C375HP/Z375HP275 (125)34 (86)39 (99)46 (117)
C575HP/Z575HP375 (170)34 (86)39 (99)46 (117)
Z700HP 34 (86)39 (99)46 (117)



Model Weight
C250HP/Z250HP200 (90)32 (81.3)38 (96.5)31 (78.8)
C375HP/Z375HP250 (114)32 (81.3)38 (96.5)39 (99)
C575HP/Z575HP350 (158)32 (81.3)38 (96.5)39 (99)



For tips on installation, please see our FAQs and  Installation pages

Product Literature

Please click the links below to download pdf brochures for Heat Siphon products


For more information, also see the manufacturer’s web site at:-



All Heat Siphon units are delivered direct from the manufacturer in
the USA. The normal delivery time is approximately 2-3 weeks from order.

We can ship these units direct from the USA to any European country. This can often work out much cheaper.

Please contact us for further information on shipping costs to different European countries.


Note: We offer an additional 1% discount on these prices for payment by debit card or bank transfer.  Just choose bank transfer or debit card as the payment type when you complete the checkout process.


If you need any assistance or advice as to which model would be best for your pool, please email us

for more information, also see our FAQs page

All items sold in accordance with our terms and conditions

for all enquiries, please contact us at enquiries@heatpumps4pools.com


We accept all major credit and debit cards, Bank Transfer (BACS) and Paypal

All major credit cards accepted

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The prices shown include FREE UK delivery for orders over £50 or £6.50 for orders under £50

We can ship to any country. Please contact us for a shipping quote.

The lead time on most items is normally on a 1-2 day delivery,  subject to availability. Please call to check availability.

Additional information

Weight102 kg