Quick Guide to Choosing Your PTR Valve

Picking the right PTR (Pressure & Temperature Relief) valve is as simple as matching three things: pipe size, pressure setting, and whether you need insulation (E) or an extended test lever (T). Heres a streamlined decision flowno plumbing PhD required.

1. Size: 12 mm vs. 20 mm

• 12 mm ():
  • Standard residential tanks (150 L), small apartments, instant hot-water units.
  • Quieter, fits in tight spots.
• 20 mm ():
  • Larger cylinders (150 L), multi-bath homes, light-commercial (cafs, laundries).
  • Higher flowavoids chug-chug under heavy draw.

Rule of Thumb: Match your existing relief valve inlet. If in doubt and your heater is under ~150 L, go 12 mm.

2. Pressure Setting (KPa)

Choose a valve rated just above your tanks working pressure and no higher than its max. Common settings:

• 700 KPa: Low-pressure mains (<600 KPa).
• 850 KPa: Most metro homes (450900 KPa mains).
• 1 000 KPa: High-pressure areas (9001 100 KPa mains).
• 1 400 KPa: Very high-pressure systems or multi-storey/commercial tanks.

Check your tanks label or manual. If it specifies relief = 850 KPa, pick an 850 KPa valve. Never undersize or oversize beyond the tanks rating.

3. Extras: E (Insulation) & T (Test Lever)

• E (Energy/Efficiency):
  • Adds a snap-on polyurethane jacket.
  • Reduces heat loss and helps prevent freezing in unconditioned spaces (cold roofs, garages).
• T (Test Lever Extension):
  • Provides a longer stainless-steel lever for easy annual testing if the valve sits in hard-to-reach spots (under decking, in roof voids).

You can combine bothe.g., HTE55-1850 KPa (12 mm insulated @850 KPa) or HTT575-11000 KPa (20 mm extended lever @1 000 KPa).

4. Model Decoding

• HT55-850 KPa: 12 mm standard @850 KPa.
• HTE55-1-1000 KPa: 12 mm insulated @1 000 KPa.
• HTT575-1-1400 KPa: 20 mm extended lever @1 400 KPa.

5. Final Checklist

1. Pipe Diameter: 12 mm; 20 mm.
2. Pressure Rating: Match your heaters Max Relief Setting (700/850/1000/1400 KPa).
3. Extras (Optional):
   • Add E if the valve sits in a cold or uninsulated location.
   • Add T if its hard to reach.

Example:

• Residential tank in a conditioned plant room, mains ~700 KPa 12 mm HT55-850 KPa.
• Large solar system in an uninsulated roof, mains ~900 KPa 20 mm HTE575-1-1000 KPa.

Match size, match pressure, add E for insulation or T for lever extensionand thats it. Your PTR valve will keep your hot-water system safe, compliant, and drip-free.