Key Takeaways
- Be aware of what maintenance is required for your unit - in many cases the warranty will be void if proper maintenance has not been carried out
- Some units require more ongoing maintenance than others (and it’s not just cheaper units)
- Most units require a service every five years
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Heat pump hot water units have a number of moving parts. It’s important that you are aware of maintenance requirements for your unit, to give it the best chance of lasting a long time and meeting warranty conditions.
While I wouldn’t choose a unit simply because it requires less maintenance, it can be very helpful in deciding between two units which are otherwise quite similar. I suggest people place a premium on units which require less maintenance.
I have reviewed every owner's manual on the market. Below I highlight common maintenance requirements.
Minor Maintenance - Every 6 or 12 months
Most manufacturers require simple ongoing maintenance of units. Generally they require dwelling occupants to operate the PTR valve (more below), check condensate drain lines, check air flow into the units is not obstructed and give the units a light clean.
The better manuals clearly distinguish between a six- or twelve-monthly service which can be carried out by the dwelling occupant and a five year major service which should be carried out by a plumber.
Unfortunately some manufacturers require all maintenance to be carried out by licensed technicians, which seems onerous, costly and unnecessary (more below).
PTR Valve
Heat pump hot water units come with a Pressure and Temperature Relief (PTR) Valve. The PTR Valve is designed to stop the tank exploding - to release pressure built up due to water expanding during the heating cycle. It releases pressure by dripping hot water along the PTR drain line.
The PTR valve should be checked periodically to ensure it’s working. As we can see in Rinnai’s Enviroflo manual, we’re simply checking that the valve is working. Checking your PTR valve is like flossing - people should do it more frequently, but few do.
Servicing - Every 5 Years
Heat pump hot water units typically require a 5 year service (3 years for some).
A 5 year major service usually includes:
- Replacing the PTR valve (and Expansion Control Valve, if fitted)
- Replace the tempering valve
- Cleaning air filters and ensuring they are not obstructed
- Inspecting the anode. Some units require anodes to be replaced at the 5 year service, or if not at the 5 year service, within the 3 years following the service (that is, a maximum of 8 years)
- Flushing the unit - particularly those with sacrificial anodes - they commonly build up residue and sediment from the sacrificial anode
- Inspect electrical and plumbing connections
Sacrificial Anode
In What are the components in a heat pump hot water unit, I outline common tank materials and the role of a sacrificial anode. Many heat pump hot water units have one or more sacrificial anodes - metal rods that are sacrificed so the tank does not corrode. These anodes need to be regularly inspected and replaced.
Sacrificial anodes need to be checked every 3 or 5 years and replaced when required (usually a maximum of 8 years). Obviously be guided by your Owner's Manual, but if your unit has a sacrificial anode, be aware of it and the need for ongoing checks and maintenance.
Units with tanks made from stainless steel or those that come with an impressed current anode generally require less maintenance.
Maintenance Requirements Example: Emerald Units
The Emerald units are a good example of why we need to pay attention to maintenance requirements. The Emerald owner’s manuals require units to be checked every six months. Whereas many other manufacturers allow dwelling occupants to conduct maintenance, Emerald requires maintenance to be carried out by qualified personnel. Whatismore, the unit’s warranty is void if the unit is not maintained as per the owner's manual. Technically, Emerald owners need to call out a plumber every six months! This seems over the top, inconsistent with other units on the market and will lead to significant operating costs and hassle.
Maintenance Requirements Example: Reclaim Stainless Steel vs Glass Lined
Reclaim’s option for a Stainless Steel or Glass Lined tank is a great example of up-front cost compared to ongoing maintenance.
Reclaim’s tanks comes in 4 sizes: 160, 250, 315 and 400L options. They all come in Stainless Steel or Glass Lined. The 315L Glass Lined is the most popular option. The Glass Lined options are generally around $700 cheaper, but I think this is a false economy.
The Glass Lined tanks require servicing every 3 years and the sacrificial anode requires replacing every 5 years. You’ll require a plumber to attend at the end of years 3, 6 and 9, and perhaps at the end of year 5 and 10. Let’s assume a plumber’s call out and maintenance fee will be around $250, so even if there’s just three visits, you’ll be out of pocket at least $750, probably more as plumbers’ costs increase.
Further, the warranty on Glass Lined tanks is 10 years, compared to 15 years for Stainless Steel. A Stainless Steel tank therefore has three benefits:
- 5 years longer warranty
- Cheaper over the long run
- Less hassle - you don’t need to worry about calling out a plumber every few years
Reclaim tank selection is a perfect example of both a) it pays to be knowledgeable and b) a little more investment upfront will likely save you down the track.
